U.S. patent application number 16/351403 was filed with the patent office on 2019-11-14 for articles and systems involving reaction products on surfaces and associated methods.
This patent application is currently assigned to Massachusetts Institute of Technology. The applicant listed for this patent is Massachusetts Institute of Technology. Invention is credited to Maher Damak, Kripa K. Varanasi.
Application Number | 20190344274 16/351403 |
Document ID | / |
Family ID | 66182632 |
Filed Date | 2019-11-14 |
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United States Patent
Application |
20190344274 |
Kind Code |
A1 |
Varanasi; Kripa K. ; et
al. |
November 14, 2019 |
ARTICLES AND SYSTEMS INVOLVING REACTION PRODUCTS ON SURFACES AND
ASSOCIATED METHODS
Abstract
Methods related to forming reaction products on surfaces are
generally provided. Some methods comprise applying first and second
polyelectrolytes in first and second polyelectrolyte carrier fluids
to a surface. The first and second polyelectrolytes may be
different, and the first and second carrier fluids may be the same
or different. Some methods comprise forming a mixture of the first
and second polyelectrolytes in a mixture carrier fluid that
comprises the first and/or second carrier fluids. The first and
second polyelectrolyte may be removed from the mixture carrier
fluid to form a reaction product on the surface. In some
embodiments, the mixture carrier fluid comprises a salt with a
molecular weight of less than or equal to 1 kg/mol at a
concentration within the mixture carrier fluid of from 0.01 M to
0.5 M. In some embodiments, the mixture carrier fluid has a
turbidity of greater than or equal to 10 NTU and a viscosity of
less than or equal to 1 Pa*s.
Inventors: |
Varanasi; Kripa K.;
(Lexington, MA) ; Damak; Maher; (Cambridge,
MA) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Massachusetts Institute of Technology |
Cambridge |
MA |
US |
|
|
Assignee: |
Massachusetts Institute of
Technology
Cambridge
MA
|
Family ID: |
66182632 |
Appl. No.: |
16/351403 |
Filed: |
March 12, 2019 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
62641813 |
Mar 12, 2018 |
|
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|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B01L 2300/08 20130101;
A01N 59/00 20130101; B01J 13/22 20130101; B01L 3/502761 20130101;
A01N 25/24 20130101; A01N 25/10 20130101 |
International
Class: |
B01L 3/00 20060101
B01L003/00; B01J 13/22 20060101 B01J013/22 |
Claims
1. An article comprising: a product disposed on a surface, wherein:
the product is formed by removing a first polyelectrolyte and a
second polyelectrolyte from a mixture carrier fluid, the mixture
carrier fluid is formed from a first carrier fluid comprising a
first polyelectrolyte and a second carrier fluid comprising a
second polyelectrolyte, and the mixture carrier fluid comprises a
salt with a molecular weight of less than or equal to 1 kg/mol at a
concentration within the mixture carrier fluid of from 0.01 M to
0.5 M.
2. An article comprising: a product disposed on a surface, wherein:
the product is formed by removing a first polyelectrolyte and a
second polyelectrolyte from a mixture carrier fluid, the mixture
carrier fluid is formed from a first carrier fluid comprising a
first polyelectrolyte and a second carrier fluid comprising a
second polyelectrolyte, and the mixture carrier fluid has a
turbidity of greater than or equal to 10 NTU and a viscosity of
less than or equal to 1 Pa*s.
3. An article as in claim 1, wherein the molecular weight of the
salt is less than or equal to 200 g/mol.
4. An article as in claim 1, wherein the concentration of the salt
within the mixture carrier fluid is from 0.05 M to 0.2 M.
5-6. (canceled)
7. An article as in claim 1, wherein an absolute value of a zeta
potential of the first polyelectrolyte in the mixture carrier fluid
is greater than or equal to 5 mV and an absolute value of a zeta
potential of the second polyelectrolyte in the mixture carrier
fluid is greater than or equal to 5 mV.
8. An article as in claim 1, wherein an absolute value of a zeta
potential of the first polyelectrolyte in the mixture carrier fluid
is greater than or equal to 20 mV and an absolute value of a zeta
potential of the second polyelectrolyte in the mixture carrier
fluid is greater than or equal to 20 mV.
9-10. (canceled)
11. An article as in claim 1, wherein a concentration of the first
polyelectrolyte in the mixture carrier fluid is from 1 mM to 30
mM.
12. An article as in claim 1, wherein a concentration of the first
polyelectrolyte in the mixture carrier fluid is from 5 mM to 20
mM.
13. An article as in claim 1, wherein a concentration of the first
polyelectrolyte in the mixture carrier fluid is from 1 mM to 30 mM
and a concentration of the second polyelectrolyte in the mixture
carrier fluid is from 1 mM to 30 mM.
14. (canceled)
15. An article as in claim 1, wherein the mixture carrier fluid
further comprises an agricultural chemical.
16. An article as in claim 15, wherein the agricultural chemical is
a pesticide.
17. An article as in claim 1, wherein the surface comprises a
portion of a plant.
18-19. (canceled)
20. An article as in claim 1, wherein the surface has a roughness
of from 20 nm to 10 microns.
21-23. (canceled)
24. An article as in claim 1, wherein the article comprises a
composition applied to the surface after applying the first and
second polyelectrolytes to the surface.
25. An article as in claim 24, wherein the composition comprises
water.
26. An article as in claim 24, wherein the composition further
comprises an agricultural chemical.
27. An article as in claim 1, wherein a turbidity of the mixture
carrier fluid is greater than or equal to 100 NTU.
28. An article as in claim 1, wherein a viscosity of the mixture
carrier fluid is less than or equal to 0.1 Pa*s.
29. An article as in claim 1, wherein at least a portion of the
first polyelectrolyte and/or at least a portion of the second
polyelectrolyte is not removed from the mixture carrier fluid.
30. A composition and/or kit, comprising: a first polyelectrolyte
in a first carrier fluid; and a second polyelectrolyte in a second
carrier fluid, wherein: the first and second polyelectrolytes are
different, the first and second carrier fluids are configured to
form a mixture carrier fluid that comprises the first and/or second
carrier fluids, and the mixture carrier fluid comprises a salt with
a molecular weight of less than or equal to 1 kg/mol at a
concentration within the mixture carrier fluid of from 0.01 M to
0.5 M.
31-91. (canceled)
Description
RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. .sctn.
119(e) to U.S. Provisional Application No. 62/641,813, filed Mar.
12, 2018, and entitled "Methods of Forming Reaction Products on
Surfaces and Associated Articles and Systems", which is
incorporated herein by reference in its entirety and for all
purposes.
FIELD
[0002] The present invention generally relates to methods of
forming reaction products on surfaces, and associated articles and
systems.
BACKGROUND
[0003] Certain consumer products are designed to be applied to
surfaces of interest in the form of droplets. In many cases, large
fractions of the droplets applied to the surfaces bounce or roll
away prior to depositing any active ingredients therein on the
surfaces. This phenomenon causes consumers to apply excess amounts
of the products to the surfaces, resulting in waste. Accordingly,
improved methods that result in enhanced droplet retention on
surfaces may be advantageous.
SUMMARY
[0004] The present invention generally relates to articles,
systems, and methods associated with the formation of reaction
products on surfaces. The subject matter of the present invention
involves, in some cases, interrelated products, alternative
solutions to a particular problem, and/or a plurality of different
uses of one or more systems and/or articles.
[0005] Certain embodiments relate to articles. In some embodiments,
an article comprises a product disposed on a surface. The product
is formed by removing a first polyelectrolyte and a second
polyelectrolyte from a mixture carrier fluid, the mixture carrier
fluid is formed from a first carrier fluid comprising a first
polyelectrolyte and a second carrier fluid comprising a second
polyelectrolyte, and the mixture carrier fluid comprises a salt
with a molecular weight of less than or equal to 1 kg/mol at a
concentration within the mixture carrier fluid of from 0.01 M to
0.5 M.
[0006] In some embodiments, an article comprises a product disposed
on a surface. The product is formed by removing a first
polyelectrolyte and a second polyelectrolyte from a mixture carrier
fluid, the mixture carrier fluid is formed from a first carrier
fluid comprising a first polyelectrolyte and a second carrier fluid
comprising a second polyelectrolyte, and the mixture carrier fluid
has a turbidity of greater than or equal to 10 NTU and a viscosity
of less than or equal to 1 Pa*s.
[0007] Certain embodiments relate to compositions and/or kits. In
some embodiments, a composition and/or kit comprises a first
polyelectrolyte in a first carrier fluid and a second
polyelectrolyte in a second carrier fluid. The first and second
polyelectrolytes are different, the first and second carrier fluids
are configured to form a mixture carrier fluid that comprises the
first and/or second carrier fluids, the mixture carrier fluid
comprises a salt with a molecular weight of less than or equal to 1
kg/mol at a concentration within the mixture carrier fluid of from
0.01 M to 0.5 M.
[0008] In some embodiments, a composition and/or kit comprises a
first polyelectrolyte in a first carrier fluid and a second
polyelectrolyte in a second carrier fluid. The first and second
polyelectrolytes are different, the first and second carrier fluids
are configured to form a mixture carrier fluid that comprises the
first and/or second carrier fluids, and the mixture carrier fluid
has a turbidity of greater than or equal to 10 NTU and a viscosity
of less than or equal to 1 Pa*s.
[0009] Certain embodiments relate to methods. In some embodiments,
a method comprises applying to a surface a first polyelectrolyte in
a first carrier fluid and a second polyelectrolyte in a second
carrier fluid. The first and second polyelectrolytes may be
different. The first and second carrier fluids can be the same or
different. The method may further comprise forming a mixture of the
first and second polyelectrolytes in a mixture carrier fluid that
comprises the first and/or second carrier fluids. The mixture
carrier fluid may comprise a salt with a molecular weight of less
than or equal to 1 kg/mol at a concentration within the mixture
carrier fluid of from 0.01 M to 0.5 M. The method may further
comprise removing the first polyelectrolyte and the second
polyelectrolyte from the mixture carrier fluid to form a reaction
product on the surface.
[0010] In some embodiments, a method comprises applying to a
surface a first polyelectrolyte in a first carrier fluid and a
second polyelectrolyte in a second carrier fluid. The first and
second polyelectrolytes may be different. The first and second
carrier fluids can be the same or different. The method may further
comprise forming a mixture of the first and second polyelectrolytes
in a mixture carrier fluid that comprises the first and/or second
carrier fluids. The mixture carrier fluid may have a turbidity of
greater than or equal to 10 NTU and a viscosity of less than or
equal to 1 Pa*s. The method may further comprise removing the first
polyelectrolyte and the second polyelectrolyte from the mixture
carrier fluid to form a reaction product on the surface.
[0011] Other advantages and novel features of the present invention
will become apparent from the following detailed description of
various non-limiting embodiments of the invention when considered
in conjunction with the accompanying figures. In cases where the
present specification and a document incorporated by reference
include conflicting and/or inconsistent disclosure, the present
specification shall control.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] Non-limiting embodiments of the present invention will be
described by way of example with reference to the accompanying
figures, which are schematic and are not intended to be drawn to
scale. In the figures, each identical or nearly identical component
illustrated is typically represented by a single numeral. For
purposes of clarity, not every component is labeled in every
figure, nor is every component of each embodiment of the invention
shown where illustration is not necessary to allow those of
ordinary skill in the art to understand the invention. In the
figures:
[0013] FIGS. 1A-1C show one non-limiting example of a method of
forming a reaction product on a surface;
[0014] FIG. 1D shows one non-limiting example of a method of
applying a composition to a surface on which a reaction product is
disposed;
[0015] FIG. 2A is a chart showing surface coverage as a function of
pH, according to certain embodiments;
[0016] FIG. 2B is a chart showing turbidity as a function of pH,
according to certain embodiments;
[0017] FIG. 2C is a chart showing zeta potential as a function of
pH, according to certain embodiments;
[0018] FIG. 3A is a chart showing surface coverage as a function of
NaCl concentration, according to certain embodiments;
[0019] FIG. 3B is a chart showing turbidity as a function of NaCl
concentration, according to certain embodiments;
[0020] FIG. 4A is a chart showing surface coverage as a function of
polyelectrolyte concentration, according to certain
embodiments;
[0021] FIG. 4B is a chart showing turbidity as a function of
polyelectrolyte concentration, according to certain embodiments;
and
[0022] FIG. 5 is a chart showing turbidity as a function of surface
coverage, according to certain embodiments.
DETAILED DESCRIPTION
[0023] Methods related to forming reaction products on surfaces,
and associated articles and systems, are generally provided. The
methods may comprise forming reaction products on surfaces that
enhance droplet retention thereon, and/or may comprise forming
reaction products on surfaces in a manner that enhances droplet
retention thereon. For example, reaction products comprising
aggregated polyelectrolytes may form under conditions that result
in enhanced aggregation of the polyelectrolytes. As another
example, reaction products may form from polyelectrolytes present
in droplets over time scales that enhance retention of those
droplets on the surface, such as time scales shorter than the time
scale over which the droplets would interact with and then bounce
or roll off the surface. Other examples will be described in
further detail below.
[0024] Certain methods relate to forming reaction products on
surfaces from a mixture carrier fluid that has one or more features
that promote the formation of reaction products that enhance
droplet retention and/or the formation of reaction products in a
manner that enhances droplet retention. Non-limiting examples of
such features include the presence of salts in beneficial amounts,
the presence of polyelectrolytes in beneficial amounts, a pH in a
range in which the zeta potential of each polyelectrolyte therein
is within a beneficial range (e.g., above a minimal value), and a
viscosity in a beneficial range (e.g., below a maximal value). In
some embodiments, a macroscopically observable feature of the
carrier fluid, such as its turbidity, may be in a range indicative
of the mixture carrier fluid having one or more of the advantageous
properties described herein. Macroscopically observable features
may be indicative of a mixture carrier fluid from which reaction
products that enhance droplet retention may form and/or of a
mixture carrier fluid from which reaction products may form in a
manner that enhances droplet retention.
[0025] Some embodiments relate to articles, compositions, and/or
kits. An article composition, and/or kit described herein may be
related to a method described herein. By way of example, some
articles are products formed by the performance of one or more of
the methods described herein. For instance, in some embodiments, an
article comprises a product disposed on a surface and is formed
according to one or more of the methods described herein. As
another example, in some embodiments, a composition and/or a kit is
suitable for performing (and/or configured to perform) one or more
of the methods described herein. For instance, a composition and/or
a kit may comprise one or more components that may be employed in
one or more of the methods described herein, such as a first
polyelectrolyte (e.g., in a first carrier fluid) and/or a second
polyelectrolyte (e.g., in a second carrier fluid). In some
embodiments, a composition and/or a kit may be configured to form a
mixture carrier fluid described herein and/or to form a product
described herein (e.g., on a surface described herein).
[0026] In this disclosure, the phrase "reaction product" is used
interchangeably with the word "product". Both should be understood
to refer species formed by the response of one or more components
to a stimulus (e.g., exposure to another component) that causes in
the deposition of the "reaction product" or "product" on a surface.
The "reaction product" or "product" may comprise all of such
components, none of such components, or some of such
components.
[0027] FIGS. 1A-1C show one non-limiting example of a method
comprising applying first and second polyelectrolytes in first and
second carrier fluids to a surface, forming a mixture of the first
and second polyelectrolytes in a mixture carrier fluid, and
removing at least a portion of the first polyelectrolyte and at
least a portion of the second polyelectrolyte from the mixture
carrier fluid to form a reaction product on the surface.
[0028] In FIG. 1A, a first polyelectrolyte 100 in a first carrier
fluid 200 and a second polyelectrolyte 110 in a second carrier
fluid 210 are applied to a surface 300. As shown in FIG. 1A, the
first and second polyelectrolytes (and the associated first and
second carrier fluids) may be applied to the surface in a manner
such that, for a period of time, both the first and second carrier
fluids are present on the surface at the same time. The first and
second polyelectrolytes may be applied sequentially (e.g., the
first polyelectrolyte prior to the second polyelectrolyte, the
second polyelectrolyte prior to the first polyelectrolyte),
simultaneously (e.g., the first and second polyelectrolytes may be
applied to the surface at the same time), or both sequentially and
simultaneously (e.g., the first polyelectrolyte and the second
polyelectrolyte may be applied to the surface for periods of time
that partially, but not completely, overlap). The first and second
polyelectrolytes (and/or the associated first and second carrier
fluids) may be applied to portions of the surface that do not
overlap (e.g., as shown in FIG. 1A), or the first and second
polyelectrolytes (and/or the associated first and second carrier
fluids) may be applied to portions of the surface that overlap at
least partially (e.g., portions that completely overlap). The first
and second polyelectrolytes (and/or the associated first and second
carrier fluids) may together cover a variety of suitable fractions
of the surface (e.g., all of the surface, one or more
non-contiguous portions of the surface).
[0029] It should be understood that, although FIG. 1A shows
application of equal amounts of the first and second carrier fluid
to the surface and equal concentration of the first and second
polyelectrolytes in the first and second carrier fluids, other
configurations are also possible. For example, a larger volume of
the first carrier fluid may be applied than of the second carrier
fluid (or vice versa). As another example, the first
polyelectrolyte may be present in the first carrier fluid at a
higher concentration than the second polyelectrolyte in the second
carrier fluid (or vice versa). It should also be understood that
either or both of the first and second carrier fluids may further
comprise one or more species not shown in FIG. 1A (e.g., the first
and/or the second carrier fluid may comprise one or more salts). As
a third example, the first and second carrier fluids may be the
same, or they may be different. In some embodiments, such as that
shown in FIG. 1A, the first and second polyelectrolytes are
different (e.g., they have different chemical structures, they have
opposite charge).
[0030] The first and second polyelectrolytes (and the associated
first and second carrier fluids) may be applied to surfaces in a
variety of suitable manners. In some embodiments, the first and/or
second polyelectrolyte may be applied to a surface by contacting
droplets of a carrier fluid comprising the polyelectrolyte with the
surface. The droplets may be sprayed on the surface, dripped on the
surface, or contacted with the surface in another suitable manner.
Other methods of applying a polyelectrolyte to a surface are also
contemplated for application of the first polyelectrolyte to the
surface and/or application of the second polyelectrolyte to the
surface. Such methods may include pouring a carrier fluid
comprising the polyelectrolyte onto the surface, dipping the
surface in a carrier fluid comprising the polyelectrolyte, and the
like.
[0031] FIG. 1B shows one non-limiting example of a mixture carrier
fluid disposed on a surface. In FIG. 1B, a first polyelectrolyte
100 and a second polyelectrolyte 110 are mixed in a mixture carrier
fluid 220 disposed on a surface 300. In some embodiments, a first
carrier fluid and a second carrier fluid at least partially mix to
form the mixture carrier fluid. The mixture carrier fluid may
comprise at least a portion of the first carrier fluid, at least a
portion of the second carrier fluid, and/or at least a portion of
both the first carrier fluid and the second carrier fluid. In some
embodiments, at least a portion of the first carrier fluid and/or
at least a portion of the second carrier fluid may not be included
in the mixture carrier fluid. The mixture carrier fluid may further
comprise one or more species not shown in FIG. 1B, such as one or
more salts.
[0032] A mixture carrier fluid and a mixture of polyelectrolytes
therein may be formed in a variety of suitable manners. In some
embodiments, a mixture carrier fluid may be formed by topological
contact between a first carrier fluid comprising a first
polyelectrolyte and a second carrier fluid comprising a second
polyelectrolyte. The first and second carrier fluids, and the first
and second polyelectrolytes therein, may mix due to thermodynamic
driving forces. The topological contact between the carrier fluids
may be achieved by applying the first and second carrier fluids,
and the first and second polyelectrolytes therein, to a surface in
a manner that results in such contact. For instance, the first and
second carrier fluids may be applied to a surface on top of one
another and/or next to one another. In some embodiments, the first
and second carrier fluids may be placed in topological contact
prior to topological contact with a surface (e.g., for a short
period of time). As an example, the first and second carrier fluids
may be applied to the surface in the form of droplets and some such
droplets may impinge on each other prior to contact with the
surface (e.g., a first droplet comprising a first carrier fluid and
a first polyelectrolyte may impinge upon a second droplet
comprising a second carrier fluid and a second polyelectrolyte, mix
to form a droplet comprising a mixture carrier fluid and the first
and second polyelectrolytes, and then that droplet may contact the
surface).
[0033] Mixtures of two or more polyelectrolytes, such as mixtures
of first and second polyelectrolytes, may have a variety of
suitable microscopic structures. The polyelectrolytes may
interpenetrate with one another in a carrier fluid, such as a
mixture carrier fluid, to any suitable extent. In some embodiments,
both a first and second polyelectrolyte may be fully solubilized in
a mixture carrier fluid. In other embodiments, one or both of the
first and second polyelectrolyte may be at least partially phase
separated from the mixture carrier fluid and/or may be partially
phase separated from one another. The mixture carrier fluid may
comprise one or more phases comprising both the first and second
polyelectrolyte. In some embodiments, the mixture carrier fluid may
further comprise one or more additional phases lacking the first
polyelectrolyte and/or the second polyelectrolyte.
[0034] Some embodiments relate to reaction products disposed on
surfaces. The reaction product disposed on the surface may be
formed by a method as described herein, such as a method having one
or more features in common with the method shown in FIGS. 1A-1B.
FIG. 1C shows one non-limiting example a reaction product disposed
on a surface. In FIG. 1C, a reaction product 400 is disposed on a
surface 300. As shown in FIG. 1C, the reaction product may comprise
the first polyelectrolyte and the second polyelectrolyte. The
reaction product may further comprise one or more species not shown
in FIG. 1C, such as one or more salts. The reaction product may be
formed by removing at least a portion of the first and second
polyelectrolytes from a mixture carrier fluid and/or by any other
suitable method (e.g., one or more of the methods described
herein). The entirety of the first and second polyelectrolytes may
be removed from the mixture carrier fluid, or at least a portion of
the first polyelectrolyte and/or at least a portion of the second
polyelectrolyte may not be removed from the mixture carrier
fluid.
[0035] As an example of a method of forming a reaction product on a
surface from a mixture carrier fluid, at least a portion of the
first and at least a portion of the second polyelectrolyte may
precipitate from the mixture carrier fluid to form the reaction
product. All of the first and/or second polyelectrolyte present in
the mixture carrier fluid may precipitate therefrom during
formation of the reaction product, or at least a portion of the
first polyelectrolyte and at least a portion of the second
polyelectrolyte may remain in the mixture carrier fluid during
and/or after reaction product formation. As another example, the
mixture carrier fluid may evaporate from a mixture of the first and
second polyelectrolytes, leaving behind the reaction product on the
surface. As a third example, the mixture carrier fluid may bounce
or roll off the surface, leaving behind the reaction product on the
surface. In such embodiments, the mixture carrier fluid that
bounces or rolls of the surface may comprise at least a portion of
the first polyelectrolyte and/or at least a portion of the second
polyelectrolyte. In some embodiments, the reaction product may
comprise minimal amounts of the mixture carrier fluid, the first
carrier fluid, and/or the second carrier fluid.
[0036] Reaction products may form from a variety of suitable
reactions. In some embodiments, first and second polyelectrolytes
of opposite charge may interact to form the reaction product. The
first and second polyelectrolytes may be electrostatically
attracted to each other in solution and/or may release counter ions
when they interact. One or both of these factors may drive
precipitation of reaction products comprising both the first
polyelectrolyte and the second polyelectrolyte from a carrier fluid
(e.g., a mixture carrier fluid). In certain embodiments, the
reaction product may form from a coacervation reaction. Forming the
reaction product may comprise forming a polyelectrolyte complex
(e.g., a polyelectrolyte complex comprising first and second
polyelectrolytes). Other reactions, such as acid-base reactions,
may also cause reaction products to form.
[0037] A reaction product may have a variety of suitable
morphologies on a surface. In some embodiments, such as that shown
in FIG. 1C, the reaction product may cover one or more
discontinuous portions of the surface. In certain cases, the
reaction product may cover a single contiguous portion of the
surface, and/or may cover the entirety of the surface.
[0038] In some methods, one or more further steps may be performed.
The further steps may be performed after formation of a reaction
product on a surface (e.g., as a component of a method that
comprises forming a reaction product on a surface) or at another
time. One example of a further step is a step of applying a
composition to the surface. FIG. 1D shows a step of applying a
composition 500 to a surface 300 on which a reaction product 400 is
disposed. As will be described in more detail below, the
composition may comprise one, more, or none of a first carrier
fluid, a second carrier fluid, a mixture carrier fluid, a first
polyelectrolyte, and a second polyelectrolyte. The composition may
comprise one or more species configured to confer a benefit on the
surface.
[0039] If applied to a surface, a composition may be applied at a
variety of suitable points in time and at a variety of suitable
locations. For example, the composition may be applied to the
surface prior to the application of either or both of the first and
second polyelectrolytes, at the same time as the application of
either or both of the first and second polyelectrolytes, and/or
after application of either or both of the first and second
polyelectrolytes. The composition may be applied to the surface
prior to the formation of a reaction product thereon, as the
reaction product is forming thereon, and/or after the reaction
product has formed thereon. The composition may be applied to a
surface on which one, more than one, or none of the first carrier
fluid, the second carrier fluid, and the mixture carrier fluid are
disposed. The composition may be applied to portions of the surface
that lack reaction products, to portions of the surface on which
reaction products are disposed, and/or to both portions of the
surface on which reaction products are disposed and portions of the
surface on which reaction products are not disposed.
[0040] It should be understood that, if applied to a surface, a
third composition may be applied to the surface in any of the
manners described above with respect to the first and second
polymers and carrier fluids or in any other manner.
[0041] Some embodiments relate to compositions and/or kits. The
compositions and/or kits may comprise one or more components
configured to form a portion or portions of one or more of the
articles described herein (e.g., portion(s) of a carrier fluid, a
portion(s) of a mixture carrier fluid, portion(s) of a reaction
product). By way of example, a composition and/or a kit may
comprise a first polyelectrolyte and a second polyelectrolyte. The
first and second polyelectrolytes may be configured to be applied
to be applied to a surface to form a reaction product by one or
more of the methods described elsewhere herein and/or having one or
more of the properties described elsewhere herein. In some
embodiments, the first and second polyelectrolytes are configured
to be components of a mixture carrier fluid having one or more of
the properties described elsewhere herein. It should be understood
that the first and second polyelectrolytes may be provided with
first and second carrier fluids, may be configured to be added to
first and/or second carrier fluids not provided therewith (i.e.,
first and/or second carrier fluids that do not form a portion of
the composition and/or kit), or may be configured to be introduced
to a mixture carrier fluid in another manner.
[0042] In some embodiments, one or more of the first carrier fluid,
second carrier fluid, and mixed carrier fluid may comprise water.
In other words, the first second carrier fluid, second carrier
fluid, and/or mixed carrier fluid may be aqueous fluid(s).
[0043] In some embodiments, one or more carrier fluids (e.g., a
first carrier fluid, a second carrier fluid, a mixture carrier
fluid) may comprise a salt. Without wishing to be bound by any
particular theory, it is believed that the presence of a salt in
the mixture carrier fluid may enhance the formation of reaction
products with advantageous properties. It is believed that the salt
may weaken electrostatic interactions between oppositely charged
polyelectrolytes, which may promote enhanced polyelectrolyte
aggregation when the salt is present in low amounts and reduced
polyelectrolyte aggregation when the salt is present in high
amounts. It is believed that mixture carrier fluids that comprise
an amount of salt that leads to a desired level and/or rate of
polyelectrolyte aggregation (e.g., a level of polyelectrolyte
aggregation that promotes the formation of reaction products that
enhance droplet retention, polyelectrolyte aggregation at a rate
that enhances droplet retention) may be beneficial.
[0044] In some embodiments, a salt present in a carrier fluid
(e.g., a first carrier fluid, a second carrier fluid, a mixture
carrier fluid) may have a relatively low molecular weight. The
molecular weight of the salt may be less than or equal to 1 kg/mol,
less than or equal to 750 g/mol, less than or equal to 500 g/mol,
or less than or equal to 200 g/mol. The molecular weight of the
salt may be greater than 0 g/mol, greater than or equal to 100
g/mol, greater than or equal to 200 g/mol, greater than or equal to
500 g/mol, or greater than or equal to 750 g/mol. Combinations of
the above-referenced ranges are also possible (e.g., from 0 g/mol
to 1 kg/mol, or from 0 g/mol to 200 g/mol). Other ranges are also
possible.
[0045] When present, the salt may comprise a variety of suitable
cations. The salt may comprise monovalent cations, divalent
cations, trivalent cations, tetravalent cations, and/or cations of
higher valency. The salt may comprise monatomic cations and/or
polyatomic cations. Non-limiting examples of suitable cations
include Li.sup.+, Na.sup.+, K.sup.+, Be.sup.2+, Mg.sup.2+,
Ca.sup.2+, and Ba.sup.2+.
[0046] When present, the salt may comprise a variety of suitable
anions. The salt may comprise monovalent anions, divalent anions,
trivalent anions, tetravalent anions, and/or anions of higher
valency. The salt may comprise monatomic anions and/or polyatomic
anions. Non-limiting examples of suitable anions include F.sup.-,
Cl.sup.-, BP, I.sup.-, O.sup.2-, S.sup.2-, and CO.sub.3.sup.2-.
[0047] Non-limiting examples of suitable salts include LiI, NaCl,
NaBr, Na.sub.2O, KCl, K.sub.2S, BeCl.sub.2, BeO, MgCl.sub.2, MgO,
MgCO.sub.3, CaCl.sub.2, CaI.sub.2, CaS, CaCO.sub.3, BaF.sub.2, and
BaO.
[0048] A salt may be present in a carrier fluid (e.g., a first
carrier fluid, a second carrier fluid, a mixture carrier fluid) at
a variety of suitable concentrations. The concentration of the salt
in the carrier fluid may be greater than or equal to 0.01 M,
greater than or equal to 0.02 M, greater than or equal to 0.05 M,
greater than or equal to 0.1 M, greater than or equal to 0.2 M,
greater than or equal to 0.3 M, or greater than or equal to 0.4 M.
The concentration of the salt in the carrier fluid may be less than
or equal to 0.5 M, less than or equal to 0.4 M, less than or equal
to 0.3 M, less than or equal to 0.2 M, less than or equal to 0.1 M,
less than or equal to 0.05 M, or less than or equal to 0.02 M.
Combinations of the above-referenced ranges are also possible
(e.g., from 0.01 M to 0.5 M, or from 0.05 M to 0.2 M). Other ranges
are also possible.
[0049] As described above, certain embodiments relate to
polyelectrolytes in carrier fluids and/or reaction products (e.g.,
first polyelectrolytes, second polyelectrolytes). Some embodiments
relate to polyelectrolytes in compositions and/or kits. A variety
of suitable polyelectrolytes may be employed. The polyelectrolytes
may include polymers comprising one or more repeating units that
are charged in certain circumstances (e.g., in certain aqueous
carrier fluids, in certain reaction products, in all
circumstances), such as acidic groups and/or basic groups. The
polyelectrolytes may also comprise other repeating units that are
uncharged (e.g., in the same circumstances in which one or more
repeating units therein are charged). In some embodiments, one or
both of the first polyelectrolyte and the second polyelectrolyte is
a biological polyelectrolyte. Non-limiting examples of suitable
biological polyelectrolytes include polysaccharides, DNA, RNA,
chitosan, alginic acid, poly(L-lysine), poly(L-glutamic acid),
carrageenan, heparin, and hyaluronic acid. In some embodiments, one
or both of the first polyelectrolyte and the second polyelectrolyte
is a chemically modified biological polyelectrolyte, such as
pectin, chitosan, cellulose-based polyelectrolytes, starch-based
polyelectrolytes, and dextran-based polyelectrolytes. In some
embodiments, one or both of the first polyelectrolyte and the
second polyelectrolyte is a synthetic polyelectrolyte. Non-limiting
examples of synthetic polyelectrolytes include poly(ethylene imine)
(e.g., linear poly(ethylene imine)), poly(acrylic acid),
poly(vinylbenzyltrialkyl ammonium),
poly(4-vinyl-N-alkylpyridinium), poly(acryloyloxyalkyltrialkyl
ammonium), poly(acrylamidoalkyltrialkyl ammonium),
poly(diallyldimethyl ammonium), poly(styrene sulfonic acid),
poly(vinyl sulfonic acid), poly(methacrylic acid), poly(itaconic
acid), and maleic acid diallyl amine copolymers. The first and/or
second polyelectrolytes may be biodegradable and/or non-toxic.
[0050] In some embodiments, both a first polyelectrolyte and a
second polyelectrolyte may be present in a carrier fluid (e.g., a
mixture carrier fluid). Without wishing to be bound by any
particular theory, it is believed that certain combinations of the
concentration of the first polyelectrolyte in the carrier fluid and
the second polyelectrolyte in the carrier fluid may be
advantageous. It is believed that carrier fluids in which the
concentration of the first polyelectrolyte and/or the concentration
of the second polyelectrolyte are low may hinder reaction product
formation such that the reaction products that form therefrom cover
an undesirably low area fraction of a surface on which the mixture
carrier fluid is disposed and/or form too slowly to arrest
appreciable droplet bouncing or rolling off the surface. It is
believed that carrier fluids in which both the concentration of the
first polyelectrolyte and the concentration of the second
polyelectrolyte are high may form gels instead of precipitating
reaction products onto the surface. Carrier fluids in which both
the first polyelectrolyte and the second polyelectrolyte are
present in advantageous concentrations may have neither of these
drawbacks.
[0051] A carrier fluid comprising both a first polyelectrolyte and
a second polyelectrolyte (e.g., a mixture carrier fluid) may
comprise both the first polyelectrolyte and the second
polyelectrolyte in an amount of greater than or equal to 1 mM,
greater than or equal to 2 mM, greater than or equal to 5 mM,
greater than or equal to 10 mM, or greater than or equal to 20 mM.
The concentration of the first polyelectrolyte in the carrier fluid
and the concentration of the second polyelectrolyte in the carrier
fluid may both be less than or equal to 30 mM, less than or equal
to 20 mM, less than or equal to 10 mM, less than or equal to 5 mM,
or less than or equal to 2 mM. Combinations of the above-referenced
ranges are also possible (e.g., from 1 mM to 30 mM, from 5 mM to 20
mM). Other ranges are also possible.
[0052] A first polyelectrolyte, if present in a carrier fluid
(e.g., a first carrier fluid, a mixture carrier fluid), may be
present at a variety of suitable concentrations in the carrier
fluid. The concentration of the first polyelectrolyte in the
carrier fluid (e.g., first carrier fluid, mixture carrier fluid)
may be greater than or equal to 1 mM, greater than or equal to 2
mM, greater than or equal to 5 mM, greater than or equal to 10 mM,
or greater than or equal to 20 mM. The concentration of the first
polyelectrolyte in the carrier fluid (e.g., first carrier fluid,
mixture carrier fluid) may be less than or equal to 30 mM, less
than or equal to 20 mM, less than or equal to 10 mM, less than or
equal to 5 mM, or less than or equal to 2 mM. Combinations of the
above-referenced ranges are also possible (e.g., from 1 mM to 30
mM, from 5 mM to 20 mM). Other ranges are also possible.
[0053] A second polyelectrolyte, if present in a carrier fluid
(e.g., a second carrier fluid, a mixture carrier fluid), may be
present at a variety of suitable concentrations in the carrier
fluid. The concentration of the second polyelectrolyte in the
carrier fluid (e.g., second carrier fluid, mixture carrier fluid)
may be greater than or equal to 1 mM, greater than or equal to 2
mM, greater than or equal to 5 mM, greater than or equal to 10 mM,
or greater than or equal to 20 mM. The concentration of the second
polyelectrolyte in the carrier fluid (e.g., second carrier fluid,
mixture carrier fluid) may be less than or equal to 30 mM, less
than or equal to 20 mM, less than or equal to 10 mM, less than or
equal to 5 mM, or less than or equal to 2 mM. Combinations of the
above-referenced ranges are also possible (e.g., from 1 mM to 30
mM, from 5 mM to 20 mM). Other ranges are also possible.
[0054] In some embodiments, a mixture carrier fluid may have a pH
that is advantageous. Without wishing to be bound by any particular
theory, it is believed that polyelectrolyte charge varies with pH.
It is believed that lower values of pH favor protonation of acids
and higher values of pH favor deprotonation of acids. Accordingly,
polyelectrolytes comprising acidic groups that are neutral when
protonated tend to be neutrally charged at lower values of pH and
negatively charged at higher values of pH (polyelectrolytes
comprising acidic groups that are positively charged when
protonated tend to be positively charged at lower values of pH and
less positively charged, neutrally charged, or negatively charged
at higher values of pH). It is believed that when the pH of the
mixture carrier fluid is equivalent to the pKa of the
polyelectrolyte, half of the acidic groups thereon are protonated
and half of the acidic groups thereon are deprotonated. For a given
polyelectrolyte with a given pKa, certain values of pH of the
mixture carrier fluid may result in the polyelectrolyte having a
higher level of charge. As an example, increasing the pH of the
mixture carrier fluid may increase the absolute value of the
polyelectrolyte charge for polyelectrolytes that become negatively
charged when deprotonated. As another example, decreasing the pH of
the mixture carrier fluid may increase the absolute value of the
polyelectrolyte charge for polyelectrolytes that become positively
charged when protonated.
[0055] In some embodiments, it may be beneficial for a mixture
carrier fluid to comprise two polyelectrolytes of opposite charge
(e.g., a first polyelectrolyte with a first charge and a second
polyelectrolyte with a second, opposite, charge), each of which
have a charge with an absolute value in excess of a certain amount.
Such polyelectrolytes may interact favorably, as described
elsewhere herein. The pH of the mixture carrier fluid may be
selected such that it is above the pKa of the negatively charged
polyelectrolyte (e.g., the first polyelectrolyte, the second
polyelectrolyte) and below the pKa of the positively charged
polyelectrolyte (e.g., the first polyelectrolyte, the second
polyelectrolyte). The pH of the mixture carrier fluid may be
greater than or equal to 3, greater than or equal to 3.5, greater
than or equal to 4, greater than or equal to 4.5, greater than or
equal to 5, greater than or equal to 5.5, greater than or equal to
6, greater than or equal to 6.5, greater than or equal to 7, or
greater than or equal to 7.5. The pH of the mixture carrier fluid
may be less than or equal to 8, less than or equal to 7.5, less
than or equal to 7, less than or equal to 6.5, less than or equal
to 6, less than or equal to 5.5, less than or equal to 5, less than
or equal to 4.5, less than or equal to 4, or less than or equal to
3.5. Combinations of the above-referenced ranges are also possible
(e.g., from 3 to 8, or from 5 to 7). Other ranges are also
possible. The pH of the mixture carrier fluid may be determined
with a pH meter.
[0056] The pH of the first carrier fluid, if present, may be a
variety of suitable values. The pH of the first carrier fluid may
be greater than or equal to 3, greater than or equal to 3.5,
greater than or equal to 4, greater than or equal to 4.5, greater
than or equal to 5, greater than or equal to 5.5, greater than or
equal to 6, greater than or equal to 6.5, greater than or equal to
7, or greater than or equal to 7.5. The pH of the first carrier
fluid may be less than or equal to 8, less than or equal to 7.5,
less than or equal to 7, less than or equal to 6.5, less than or
equal to 6, less than or equal to 5.5, less than or equal to 5,
less than or equal to 4.5, less than or equal to 4, or less than or
equal to 3.5. Combinations of the above-referenced ranges are also
possible (e.g., from 3 to 8, or from 5 to 7). Other ranges are also
possible. The pH of the first carrier fluid may be determined with
a pH meter.
[0057] The pH of the second carrier fluid, if present, may be a
variety of suitable values. The pH of the second carrier fluid may
be greater than or equal to 3, greater than or equal to 3.5,
greater than or equal to 4, greater than or equal to 4.5, greater
than or equal to 5, greater than or equal to 5.5, greater than or
equal to 6, greater than or equal to 6.5, greater than or equal to
7, or greater than or equal to 7.5. The pH of the second carrier
fluid may be less than or equal to 8, less than or equal to 7.5,
less than or equal to 7, less than or equal to 6.5, less than or
equal to 6, less than or equal to 5.5, less than or equal to 5,
less than or equal to 4.5, less than or equal to 4, or less than or
equal to 3.5. Combinations of the above-referenced ranges are also
possible (e.g., from 3 to 8, or from 5 to 7). Other ranges are also
possible. The pH of the second carrier fluid may be determined with
a pH meter.
[0058] As described above, it may be advantageous for one or more
polyelectrolytes present in one or more carrier fluids (e.g., a
first polyelectrolyte in a first carrier fluid, a second
polyelectrolyte in a second carrier fluid, a first polyelectrolyte
in a mixture carrier fluid, a second polyelectrolyte in a mixture
carrier fluid, both a first and second polyelectrolyte in a mixture
carrier fluid) to have a charge with an absolute value in excess of
a certain amount. The zeta potential of the polyelectrolyte may be
indicative of its charge. Accordingly, it may be advantageous for
one or more polyelectrolytes in one or more carrier fluids to have
a zeta potential in excess of a certain amount.
[0059] In some embodiments, an absolute value of a zeta potential
of a first polyelectrolyte in a first carrier fluid is greater than
or equal to 5 mV, greater than or equal to 10 mV, greater than or
equal to 15 mV, greater than or equal to 20 mV, greater than or
equal to 50 mV, greater than or equal to 75 mV, or greater than or
equal to 100 mV. The absolute value of the zeta potential of the
first polyelectrolyte in the first carrier fluid may be less than
or equal to 120 mV, less than or equal to 100 mV, less than or
equal to 75 mV, less than or equal to 50 mV, less than or equal to
20 mV, less than or equal to 15 mV, or less than or equal to 10 mV.
Combinations of the above-referenced ranges are also possible
(e.g., from 5 mV to 120 mV, or from 20 mV to 120 mV). Other ranges
are also possible. It should be understood that absolute values of
zeta potentials refer to the magnitude of the zeta potential (e.g.,
a polyelectrolyte with a zeta potential with an absolute value of
greater than or equal to 5 mV may have a zeta potential of greater
than or equal to 5 mV or may have a zeta potential of less than or
equal to -5 mV). The zeta potential of the first polyelectrolyte in
the first carrier fluid may be determined by a commercially
available zeta sizer.
[0060] In some embodiments, an absolute value of a zeta potential
of a first polyelectrolyte in a mixture carrier fluid is greater
than or equal to 5 mV, greater than or equal to 10 mV, greater than
or equal to 15 mV, greater than or equal to 20 mV, greater than or
equal to 50 mV, greater than or equal to 75 mV, or greater than or
equal to 100 mV. The absolute value of the zeta potential of the
first polyelectrolyte in the mixture carrier fluid may be less than
or equal to 120 mV, less than or equal to 100 mV, less than or
equal to 75 mV, less than or equal to 50 mV, less than or equal to
20 mV, less than or equal to 15 mV, or less than or equal to 10 mV.
Combinations of the above-referenced ranges are also possible
(e.g., from 5 mV to 120 mV, or from 20 mV to 120 mV). Other ranges
are also possible. It should be understood that absolute values of
zeta potentials refer to the magnitude of the zeta potential (e.g.,
a polyelectrolyte with a zeta potential with an absolute value of
greater than or equal to 5 mV may have a zeta potential of greater
than or equal to 5 mV or may have a zeta potential of less than or
equal to -5 mV). The zeta potential of the first polyelectrolyte in
the mixture carrier fluid may be determined by a commercially
available zeta sizer.
[0061] In some embodiments, an absolute value of a zeta potential
of a second polyelectrolyte in a second carrier fluid is greater
than or equal to 5 mV, greater than or equal to 10 mV, greater than
or equal to 15 mV, greater than or equal to 20 mV, greater than or
equal to 50 mV, greater than or equal to 75 mV, or greater than or
equal to 100 mV. The absolute value of the zeta potential of the
second polyelectrolyte in the second carrier fluid may be less than
or equal to 120 mV, less than or equal to 100 mV, less than or
equal to 75 mV, less than or equal to 50 mV, less than or equal to
20 mV, less than or equal to 15 mV, or less than or equal to 10 mV.
Combinations of the above-referenced ranges are also possible
(e.g., from 5 mV to 120 mV, or from 20 mV to 120 mV). Other ranges
are also possible. It should be understood that absolute values of
zeta potentials refer to the magnitude of the zeta potential (e.g.,
a polyelectrolyte with a zeta potential with an absolute value of
greater than or equal to 5 mV may have a zeta potential of greater
than or equal to 5 mV or may have a zeta potential of less than or
equal to -5 mV). The zeta potential of the second polyelectrolyte
in the second carrier fluid may be determined by a commercially
available zeta sizer.
[0062] In some embodiments, an absolute value of a zeta potential
of a second polyelectrolyte in a mixture carrier fluid is greater
than or equal to 5 mV, greater than or equal to 10 mV, greater than
or equal to 15 mV, greater than or equal to 20 mV, greater than or
equal to 50 mV, greater than or equal to 75 mV, or greater than or
equal to 100 mV. The absolute value of the zeta potential of the
second polyelectrolyte in the mixture carrier fluid may be less
than or equal to 120 mV, less than or equal to 100 mV, less than or
equal to 75 mV, less than or equal to 50 mV, less than or equal to
20 mV, less than or equal to 15 mV, or less than or equal to 10 mV.
Combinations of the above-referenced ranges are also possible
(e.g., from 5 mV to 120 mV, or from 20 mV to 120 mV). Other ranges
are also possible. It should be understood that absolute values of
zeta potentials refer to the magnitude of the zeta potential (e.g.,
a polyelectrolyte with a zeta potential with an absolute value of
greater than or equal to 5 mV may have a zeta potential of greater
than or equal to 5 mV or may have a zeta potential of less than or
equal to -5 mV). The zeta potential of the second polyelectrolyte
in the mixture carrier fluid may be determined by a commercially
available zeta sizer.
[0063] In some embodiments, absolute values of both a first
polyelectrolyte and a second polyelectrolyte in a mixture carrier
fluid are greater than or equal to 5 mV, greater than or equal to
10 mV, greater than or equal to 15 mV, greater than or equal to 20
mV, greater than or equal to 50 mV, greater than or equal to 75 mV,
or greater than or equal to 100 mV. The absolute values of the zeta
potentials of both the first polyelectrolyte and the second
polyelectrolyte in the mixture carrier fluid may be less than or
equal to 120 mV, less than or equal to 100 mV, less than or equal
to 75 mV, less than or equal to 50 mV, less than or equal to 20 mV,
less than or equal to 15 mV, or less than or equal to 10 mV.
Combinations of the above-referenced ranges are also possible
(e.g., from 5 mV to 120 mV, or from 20 mV to 120 mV). Other ranges
are also possible. The first polyelectrolyte and the second
polyelectrolyte typically have opposite values of zeta potential
(e.g., when both the first polyelectrolyte and the second
polyelectrolyte have zeta potentials with an absolute value of
greater than or equal to 5 mV, the first polyelectrolyte may have a
zeta potential of greater than or equal to 5 mV in the mixture
carrier fluid and the second polyelectrolyte may have a zeta
potential of less than or equal to -5 mV in the mixture carrier
fluid). The zeta potential of the first and second polyelectrolytes
in the mixture carrier fluid may be determined by a commercially
available zeta sizer.
[0064] In some embodiments, a carrier fluid (e.g., a first carrier
fluid, a second carrier fluid, a mixture carrier fluid) may have a
viscosity that is advantageous. Without wishing to be bound by any
particular theory, it is believed that the viscosity of the carrier
fluid may be indicative of one or more properties of the carrier
fluid that affect its utility for forming advantageous reaction
products. As an example, high viscosities may be indicative of gels
while lower viscosities may be indicative of fluids that are not
gels. In certain cases, it may be desirable for certain carrier
fluids not to be gels. A carrier fluid (e.g., a first carrier
fluid, a second carrier fluid, a mixture carrier fluid) may have a
viscosity of less than or equal to 1 Pa*s, less than or equal to
0.5 Pa*s, less than or equal to 0.2 Pa*s, or less than or equal to
0.1 Pa*s. The viscosity of the carrier fluid may be determined by a
viscometer.
[0065] A carrier fluid (e.g., a first carrier fluid, a second
carrier fluid, a mixture carrier fluid) may have a variety of
suitable turbidities. Without wishing to be bound by any particular
theory, it is believed that certain values of turbidity may be
indicative of one or more properties of the carrier fluid that
affect its utility for forming advantageous reaction products. As
an example, higher values of turbidity may be indicative of carrier
fluids comprising a large number of reaction products and/or
reaction products of an appreciable size. High values of turbidity
may be indicative of a desirable extent of reaction product
formation. The turbidity of a carrier fluid from which the
formation of reaction products is desirable (e.g., a mixture
carrier fluid) may be greater than or equal to 10 NTU, greater than
or equal to 20 NTU, greater than or equal to 50 NTU, or greater
than or equal to 100 NTU. The turbidity of the carrier fluid may be
determined by a nephelometer.
[0066] As described above, certain methods may further comprise
applying a composition to a surface (e.g., a composition other than
a first polyelectrolyte in a first carrier fluid, a second
polyelectrolyte in a second carrier fluid, and a mixture carrier
fluid; a composition that comprises one or more of the first
polyelectrolyte in the first carrier fluid, the second
polyelectrolyte in the second carrier fluid, and/or a mixture
carrier fluid). The composition may be provided with a composition
and/or kit further comprising a first polyelectrolyte and a second
polyelectrolyte (and, optionally, a first carrier fluid and/or a
second carrier fluid) as described elsewhere herein or may be
provided separately. In some embodiments, a composition and/or kit
as described elsewhere herein is configured to be mixed with the
relevant composition and/or applied with the relevant composition
to a surface. The composition may comprise water. In other words,
the composition may be an aqueous composition.
[0067] In some embodiments, a carrier fluid (e.g., a first carrier
fluid, a second carrier fluid, a mixture carrier fluid), a
composition (e.g., a composition applied to the surface prior to
the application of either or both of the first and second
polyelectrolytes, at the same time as the application of either or
both of the first and second polyelectrolytes, and/or after
application of either or both of the first and second
polyelectrolytes; a composition applied to a surface prior to the
formation of a reaction product thereon, as the reaction product is
forming thereon, and/or after the reaction product has formed
thereon; a composition applied to a surface on which one, more than
one, or none of the first carrier fluid, the second carrier fluid,
and the mixture carrier fluid are disposed), and/or a reaction
product may further comprise one or more additional species. The
additional species may be an active agent, such as a species that
confers a beneficial property onto the carrier fluid and/or a
surface on which the carrier fluid is disposed (and/or configured
to be disposed), such as pest resistance, coloration, flavoring,
etc. Non-limiting examples of suitable active agents include
agricultural chemicals (e.g., pesticides, herbicides, fertilizers,
nutrients), pigments, paints, flavorings, pharmaceutically active
ingredients, cosmetics, anti-icing liquids, and fire retardant
species. In some embodiments, the active agent may be a pesticide
that comprises one or more of dichlorodiphenyltrichloroethane
(DDT), hexachlorocyclohexane (HCH), and pentachlorophenol
(PCP).
[0068] As described above, certain methods comprise applying one or
more fluids (e.g., a first carrier fluid, a second carrier fluid, a
composition comprising a fluid) to a surface. A wide variety of
surfaces may be employed. For example, the surface may be a portion
of a plant, such as a portion of a leaf, a portion of a root, a
portion of a fruit, a portion of a vegetable, and/or a portion of a
flower. In some embodiments, the surface may be a portion of a
fungus and/or a portion of an insect. In some embodiments, the
surface may comprise a portion of a produce item or a surface of a
form of vegetation. In certain embodiments, the surface may
comprise an edible non-toxic item such as a food item.
[0069] A surface as described herein may have a variety of suitable
roughnesses. The roughness of the surface may be greater than or
equal to 1 nm, greater than or equal to 2 nm, greater than or equal
to 5 nm, greater than or equal to 10 nm, greater than or equal to
20 nm, greater than or equal to 50 nm, greater than or equal to 100
nm, greater than or equal to 200 nm, greater than or equal to 500
nm, greater than or equal to 1 micron, greater than or equal to 2
microns, greater than or equal to 5 microns, greater than or equal
to 10 microns, greater than or equal to 20 microns, or greater than
or equal to 50 microns. The roughness of the surface may be less
than or equal to 100 microns, less than or equal to 50 microns,
less than or equal to 20 microns, less than or equal to 10 microns,
less than or equal to 5 microns, less than or equal to 2 microns,
less than or equal to 1 micron, less than or equal to 500 nm, less
than or equal to 200 nm, less than or equal to 100 nm, less than or
equal to 50 nm, less than or equal to 20 nm, less than or equal to
10 nm, less than or equal to 5 nm, or less than or equal to 2 nm.
Combinations of the above-referenced ranges are also possible
(e.g., from 1 nm to 100 microns, or from 20 nm to 10 microns).
Other ranges are also possible. The roughness of the surface may be
determined by atomic force microscopy.
[0070] A surface may have a variety of suitable contact angles with
water (e.g., prior to exposure to one, some, or all of a first
carrier fluid, a second carrier fluid, and a mixture carrier fluid;
prior to application of the first polyelectrolyte and/or the second
polyelectrolyte; prior to formation of the reaction product). The
water contact angle of the surface may be greater than or equal to
90.degree., greater than or equal to 100.degree., greater than or
equal to 110.degree., greater than or equal to 120.degree., greater
than or equal to 130.degree., greater than or equal to 140.degree.,
greater than or equal to 150.degree., greater than or equal to
160.degree., or greater than or equal to 170.degree.. The water
contact angle of the surface may be less than or equal to
180.degree., less than or equal to 170.degree., less than or equal
to 160.degree., less than or equal to 150.degree., less than or
equal to 140.degree., less than or equal to 130.degree., less than
or equal to 120.degree., less than or equal to 110.degree., or less
than or equal to 100.degree.. Combinations of the above-referenced
ranges are also possible (e.g., from 90.degree. to 180.degree.).
Other ranges are also possible. The water contact angle of the
surface may be determined with a goniometer.
[0071] Certain methods described herein result in the retention of
large volumes of fluid on surfaces (e.g., large volumes of one or
more of a first carrier fluid, a second carrier fluid, a mixture
carrier fluid, a composition comprising a fluid). In some
embodiments, performing a method as described herein (e.g.,
applying the first and second polyelectrolytes to the surface)
causes the surface to hold greater than or equal to 0.5 mL/cm.sup.2
of a fluid, greater than or equal to 1 mL/cm.sup.2 of a fluid,
greater than or equal to 2 mL/cm.sup.2 of a fluid, greater than or
equal to 4 mL/cm.sup.2 of a fluid, greater than or equal to 10
mL/cm.sup.2 of a fluid, greater than or equal to 20 mL/cm.sup.2 of
a fluid, or greater than or equal to 40 mL/cm.sup.2 of a fluid.
Performing a method as described herein may cause the surface to
hold less than or equal to 100 mL/cm.sup.2 of a fluid, less than or
equal to 40 mL/cm.sup.2 of a fluid, less than or equal to 20
mL/cm.sup.2 of a fluid, less than or equal to 10 mL/cm.sup.2 of a
fluid, less than or equal to 4 mL/cm.sup.2 of a fluid, less than or
equal to 2 mL/cm.sup.2 of a fluid, or less than or equal to 1
mL/cm.sup.2 of a fluid. Combinations of the above-referenced ranges
are also possible (e.g., from 0.5 mL/cm.sup.2 of a fluid to 100
mL/cm.sup.2 of a fluid, or from 4 mL/cm.sup.2 of a fluid to 40
mL/cm.sup.2 of a fluid). Other ranges are also possible. The fluid
held by the surface may be determined by determining the area of
the surface by image analysis, weighing the surface both prior to
and after to performing the method, and then dividing the increase
in weight after performing the method by the area of the
surface.
[0072] In some embodiments, a composition and/or a kit may be
provided with directions for use. The directions for use may
describe how to employ the composition and/or kit to form a
reaction product on a surface. By way of example, the directions
for use may comprise instructions for how to perform any of the
methods described herein and/or for how to form any of the articles
described herein. In some embodiments, the directions for use
describe procedures for mixing the component(s) of the composition
and/or kit with each other and/or other components not provided
therewith. As another example, the directions for use may describe
directions for applying first and second carrier fluids formed by
the composition and/or kit (and/or one or more components thereof)
to a surface. As further examples, the directions for use may
comprise storage instructions and/or instructions for assessing the
quality of first, second, and/or mixture carrier fluids (and/or
articles produced by the composition and/or kit). The directions
for use may describe further components not provided with the
composition and/or kit that may be added thereto, such as further
fluids (e.g., a fluid comprising water), additives, and/or other
suitable components.
[0073] Certain methods, articles, and systems described herein may
be related to those described in International Patent Application
No. PCT/US2016/057956, incorporated herein by reference in its
entirety.
[0074] The following examples are intended to illustrate certain
embodiments of the present invention, but do not exemplify the full
scope of the invention.
Example 1
[0075] This Example describes formulations that have enhanced
utility for retaining deposited compositions on surfaces. The
effects of pH of the formulation, salt concentration in the
formulation, and polyelectrolyte concentration in the formulation
on deposited composition retention are discussed.
[0076] It is shown that precipitate formation upon coalescence of
two droplets can be enhanced for the pH that maximizes the zeta
potential of both polyelectrolytes. Polyelectrolytes are typically
charged and have a non-zero zeta potential in a range of pH.
Precipitation occurs at values of pH where both polyelectrolytes
are charged.
[0077] It is shown compositions that contain an additional salt
(e.g., NaCl) in addition to the polyelectrolytes may be
advantageous in comparison to compositions lacking the additional
salt. It is also shown that the amount of formed surface
precipitates varies non-monotonically with salt concentration in
certain cases. It typically first increases with salt
concentration, then has a dip and reaches a local minimum, then
increases again to a second maximum and then drops continuously as
more salt is added. Formulations that have a salt concentration
corresponding to one of the two maxima (the maxima are comparable
in precipitate formation) may be advantageous. For NaCl used with
chitosan and alginate, these maxima are around 0.05 M and 0.15
M.
[0078] It is also shown that increasing polyelectrolyte
concentration may increase the surface precipitation only up to a
certain concentration, after which a plateau is reached.
Concentrations in excess of those at the plateau may not show any
additional benefit. For chitosan and alginate, the plateau is
reached at a polyelectrolyte concentration of about 20 mM.
Formulations that have concentrations that are lower or equal to
the onset of the plateau may be beneficial.
[0079] Finally, a new method to test formulations is demonstrated.
Measuring precipitate formation may be time and/or resource
consuming. In some cases, the relevant experiments may result in
data large error bars. It is shown that the turbidity of mixtures
of the two polyelectrolytes of interest may be used as a proxy for
the amount of precipitates that will form when solutions comprising
the polyelectrolytes are deposited on surfaces. Turbidity can be
directly measured with a nephelometer and is a straightforward
method that may be used to provide a quantitative comparison
between formulations. This method can be used to design new
formulations, to fine tune salt concentration, and/or to fine-tune
pH to improve efficiency before spraying. This method may be
advantageous when using hard water or other contaminated water
whose initial pH and salt concentration is unknown.
[0080] Polyelectrolytes are macromolecules. For certain
polyelectrolytes, a substantial portion of the constitutional units
has ionizable or ionic groups, or both. Polyelectrolytes may be
water soluble, and, if so, their charged groups may dissociate in
solution. Positively charged polyelectrolytes are called
polycations and negatively charged ones are called polyanions.
Certain polyelectrolytes combine the properties of polymers and
salts: their solutions may be viscous at high concentrations, and
they may be conductive. Examples of biological polyelectrolytes
include polysaccharides and DNA. Synthetic polyelectrolytes also
exist.
[0081] Polyelectrolytes can be strong or weak, depending on whether
they fully or partially dissociate in solution. Weak
polyelectrolytes are polyelectrolytes that are not fully charged in
solution; the amount to which they are charged can be tuned by
changing the pH. To quantify the electric interactions of
polyelectrolytes, the zeta potential is commonly used. The zeta
potential is the electric potential in the interfacial double layer
surrounding the polyelectrolyte, at the location of the stationary
layer of fluid attached to the molecule.
[0082] Mixing solutions containing positive and negative
polyelectrolytes can lead to the self-assembly of polyelectrolyte
complexes (PEC) in solution. PECs are polymer aggregates; certain
PECs can precipitate out of solution and form solid particles. Some
PECs may be formed in reactions that occur on microsecond scales.
Some PECs are stable through electrostatic attraction of the
oppositely charged ions. Since the interaction is electrostatic,
the formation of PECs may depend on the zeta potential of the
polyelectrolyte solutions and/or on the ionic strength of the
solutions. The formation of PECs may be determined by a number of
methods, including mass measurement of complexes, turbidity as a
proxy for particle density, viscometry, microscopy and FTIR.
[0083] Turbidity is the haziness of a fluid caused by suspended
particles. It is measured here with a nephelometer (Sper Scientific
Turbidity Meter 860040), an instrument that measures turbidity by
using a light beam of wavelength 850 nm and a light detector
located at 90.degree. from the source to measure the scattered
light by the suspended particles. This measurement may depend on
particle density in the solution, particle size, and/or particle
shape.
[0084] In this Example, the relationship between surface
precipitate formation and certain bulk properties, such as
turbidity, is investigated. Polyelectrolyte compositions at a range
of pH values, salt concentrations, and polyelectrolyte molarities
are formulated and studied to greater understand the effect of
these parameters on deposition from droplet impacts, and to
determine beneficial conditions that enhance the amount of area
covered by the precipitates. For several polyelectrolytes, there
are salt concentrations and pHs that are beneficial. It is also
seen that turbidity measurement may provide a facile way for
selecting appropriate mixtures and quantifying the surface
precipitation reaction.
[0085] The used surface here was a hydrophobic OTS-coated glass
slide. For the polyelectrolyte solutions, Chitosan (positively
charged) and Alginic Acid (negatively charged) were mixed in
various quantities, depending on the desired molarity. Using
syringes, a drop of Chitosan solution was placed onto the surface,
then a drop of Alginic Acid solution was added. After one minute, a
fab wipe was employed to dab away excess liquid (without ever
touching the wipe to the glass slide). To dry any remaining liquid,
an air gun was used. To analyze the deposition, the deposits were
imaged using a microscope and an image analysis tool was used in
order to calculate the percent of area that the deposit
covered.
Effect of pH
[0086] A range of pHs from 3 to 7 were tested, both with and
without the addition of 0.15 M NaCl. In order to make the
polyelectrolyte solutions the correct pH, HCl and NaOH were added
as needed. Four trials were conducted at each pH and salt
combination. The results are shown in FIG. 2A. In some cases, the
highest coverage occurred at pH 5 with no salt addition. Except for
solutions at pH>6, the addition of NaCl increased the number of
deposits formed. Turbidity was also recorded for each of the
trials, and the results are shown in FIG. 2B. Turbidity results
roughly reflect the variations of the coverage as a function of pH
for these experiments. The maximums are slightly shifted but the
general trends match.
[0087] The maximum in precipitate formation around pH 5 observed
here may be due to the variation of the zeta potential of the
polyelectrolytes employed (FIG. 2C). When observing the zeta
potentials of alginate and chitosan as a function of pH, it can be
seen that for low pH, alginate is not charged, while for high pH,
chitosan is not charged. The pH value of 5 occurs in the center of
the region where both polyelectrolytes are charged, at the point
where both of the zeta potentials are the highest, which may
explain the peak in deposit formation at that value.
Effect of Salt Concentration
[0088] The addition of one or more salts to the polyelectrolyte
solutions can influence their interaction. Molarities from 0 to 1 M
of NaCl were tested, with more of an emphasis on the region between
0 and 0.15 M. The following concentrations were included in the
test: 0 M, 0.05 M, 0.10 M, 0.15 M, 0.30 M, 0.60 M, 1.0 M. The pH
for this set of experiments (and the following ones) was
standardized at 5. The results can be seen in FIGS. 3A and 3B, but
essentially, apart from an outlier dip at 0.1 M NaCl, the surface
coverage increased with the addition of salt up until a peak, then
decreased. Turbidity experiments for the various salt
concentrations followed these trends.
[0089] At low concentrations, salts may enable the rearrangement of
polyelectrolyte molecules by weakening the electrostatic
interaction, which may lead to more aggregation. Once the quantity
gets too large, however, the salt may screen the charge, which may
prevent the complexes from forming. Here, the effect of salt was
found to be very dependent on the polyelectrolytes used in the case
of PECs.
Effect of Polyelectrolyte Concentration
[0090] The concentration of the polyelectrolyte solutions were also
varied, at pH 5 and both as 0 M NaCl and 0.15 M NaCl. It was
hypothesized that surface coverage would increase linearly along
with increase in polyelectrolyte concentration, and the data
supports this. FIG. 4A shows a linear relationship until 20 mmol,
after which point the solutions appear to have reached a point of
saturation. The values above 20 mmol do not continue to increase
with the same increments. A clear increase with the addition of
NaCl is also observable.
[0091] Turbidity experiments in this case show the same linear
trends (FIG. 4B) at lower polyelectrolyte concentrations, but not
at higher concentrations of polyelectrolytes. At high molarities,
the polyelectrolytes combined to form large gel-like structures
that are more transparent and cause less light scattering,
resulting in low turbidity values.
Turbidity as a Proxy
[0092] FIG. 5 shows the turbidity values as a function of surface
precipitate coverage for all the experiments done with chitosan and
alginate varying pH, ionic strength and polyelectrolyte
concentration (below saturation). Additional experiments with LPEI
and PAA were also included. It can be seen that, although there is
some scattering in the data, a linear tendency can be observed
through two orders of magnitude. This suggests that turbidity could
be used as a proxy for surface precipitate concentration, which may
provide a facile way to test and optimize new polyelectrolyte
solutions.
CONCLUSION
[0093] This Example has demonstrated a mechanism to enhance spray
deposition on hydrophobic surfaces through in-situ precipitation of
polyelectrolytes on the surface. Defects formed in-situ on the
surface during the impact can advantageously pin the impinging
droplets. A potential mechanism of precipitate formation in
coalescing droplets has been examined, which may enhance
understanding of the extent of the precipitation reaction during
droplet impacts. Methods described in this Example may allow
surface modification and deposition of the liquid of interest in
one single step. This Example also explored the effect of
polyelectrolyte concentration on droplet pinning. It was shown that
this method could work with different types of polyelectrolytes
with zeta potential high enough to interact; there are several
natural, biodegradable and readily available polyelectrolytes that
can be used. It was also shown that the beneficial polyelectrolyte
interaction could be achieved at certain values of pH and salt
concentration, and that turbidity measurements can be used as a
tool to compare efficiency. By adding small amounts of these
polyelectrolytes to sprays, the quantity of pesticides used in
agricultural applications could be significantly reduced. In
certain cases, coverage may be increased. Sprays including limited
amounts of pesticides and/or that result in increased coverage may
offer protection to the plant and/or may limit the toxic effects of
pesticides. Methods described in this Example can also be used for
other agricultural sprays, paints, and any other process that
involves sprays or droplet deposition.
[0094] While several embodiments of the present invention have been
described and illustrated herein, those of ordinary skill in the
art will readily envision a variety of other means and/or
structures for performing the functions and/or obtaining the
results and/or one or more of the advantages described herein, and
each of such variations and/or modifications is deemed to be within
the scope of the present invention. More generally, those skilled
in the art will readily appreciate that all parameters, dimensions,
materials, and configurations described herein are meant to be
exemplary and that the actual parameters, dimensions, materials,
and/or configurations will depend upon the specific application or
applications for which the teachings of the present invention
is/are used. Those skilled in the art will recognize, or be able to
ascertain using no more than routine experimentation, many
equivalents to the specific embodiments of the invention described
herein. It is, therefore, to be understood that the foregoing
embodiments are presented by way of example only and that, within
the scope of the appended claims and equivalents thereto, the
invention may be practiced otherwise than as specifically described
and claimed. The present invention is directed to each individual
feature, system, article, material, and/or method described herein.
In addition, any combination of two or more such features, systems,
articles, materials, and/or methods, if such features, systems,
articles, materials, and/or methods are not mutually inconsistent,
is included within the scope of the present invention.
[0095] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0096] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified unless clearly
indicated to the contrary. Thus, as a non-limiting example, a
reference to "A and/or B," when used in conjunction with open-ended
language such as "comprising" can refer, in one embodiment, to A
without B (optionally including elements other than B); in another
embodiment, to B without A (optionally including elements other
than A); in yet another embodiment, to both A and B (optionally
including other elements); etc.
[0097] As used herein in the specification and in the claims, "or"
should be understood to have the same meaning as "and/or" as
defined above. For example, when separating items in a list, "or"
or "and/or" shall be interpreted as being inclusive, i.e., the
inclusion of at least one, but also including more than one, of a
number or list of elements, and, optionally, additional unlisted
items. Only terms clearly indicated to the contrary, such as "only
one of" or "exactly one of," or, when used in the claims,
"consisting of," will refer to the inclusion of exactly one element
of a number or list of elements. In general, the term "or" as used
herein shall only be interpreted as indicating exclusive
alternatives (i.e. "one or the other but not both") when preceded
by terms of exclusivity, such as "either," "one of," "only one of,"
or "exactly one of." "Consisting essentially of," when used in the
claims, shall have its ordinary meaning as used in the field of
patent law.
[0098] As used herein in the specification and in the claims, the
phrase "at least one," in reference to a list of one or more
elements, should be understood to mean at least one element
selected from any one or more of the elements in the list of
elements, but not necessarily including at least one of each and
every element specifically listed within the list of elements and
not excluding any combinations of elements in the list of elements.
This definition also allows that elements may optionally be present
other than the elements specifically identified within the list of
elements to which the phrase "at least one" refers, whether related
or unrelated to those elements specifically identified. Thus, as a
non-limiting example, "at least one of A and B" (or, equivalently,
"at least one of A or B," or, equivalently "at least one of A
and/or B") can refer, in one embodiment, to at least one,
optionally including more than one, A, with no B present (and
optionally including elements other than B); in another embodiment,
to at least one, optionally including more than one, B, with no A
present (and optionally including elements other than A); in yet
another embodiment, to at least one, optionally including more than
one, A, and at least one, optionally including more than one, B
(and optionally including other elements); etc.
[0099] In the claims, as well as in the specification above, all
transitional phrases such as "comprising," "including," "carrying,"
"having," "containing," "involving," "holding," and the like are to
be understood to be open-ended, i.e., to mean including but not
limited to. Only the transitional phrases "consisting of" and
"consisting essentially of" shall be closed or semi-closed
transitional phrases, respectively, as set forth in the United
States Patent Office Manual of Patent Examining Procedures, Section
2111.03.
* * * * *