U.S. patent application number 10/064729 was filed with the patent office on 2004-02-12 for novel electrically active ionic polymer metal composites and novel methods of manufacturing them.
This patent application is currently assigned to Shahinpoor, Dr. Mohsen. Invention is credited to Ahghar, Massoud, Popa, Niculina Cristina, Shahinpoor, Mohsen.
Application Number | 20040025639 10/064729 |
Document ID | / |
Family ID | 31493948 |
Filed Date | 2004-02-12 |
United States Patent
Application |
20040025639 |
Kind Code |
A1 |
Shahinpoor, Mohsen ; et
al. |
February 12, 2004 |
Novel electrically active ionic polymer metal composites and novel
methods of manufacturing them
Abstract
Novel electrically active ionic polymer metal composite
materials and novel methods of manufacturing them by means of a
series of innovative chemical processes of first chemically
depositing none noble metal salt cations inside a cationic polymer
molecular network followed by chemical reduction of the said none
noble metal salt cations to generate reduced none noble metal
particles deposited inside the polymeric molecular network followed
by a second electro or chemo deposition and plating of a noble
metal inside and on the surfaces of the reduced none noble metallic
particles in the said polymer molecular network to protect the
first said none noble metal particles from oxidation, corrosion and
chemical degradation for prolonged sensing and actuation
applications of the said novel ionic polymer metal composite
material which generates an electrical signal with mechanical
deformation and undergoes mechanical deformation if an electric
field is imposed on it.
Inventors: |
Shahinpoor, Mohsen;
(Albuquerque, NM) ; Ahghar, Massoud; (Albuquerque,
NM) ; Popa, Niculina Cristina; (Albuquerque,
NM) |
Correspondence
Address: |
MOHSEN SHAHINPOOR
909 VIRGINIA, NE, SUITE 205
ALBERQUERQUE
NM
87108
US
|
Assignee: |
Shahinpoor, Dr. Mohsen
Environmental Robots Inc.
Albuquerque
NM
87108
|
Family ID: |
31493948 |
Appl. No.: |
10/064729 |
Filed: |
August 9, 2002 |
Current U.S.
Class: |
75/722 ;
205/109 |
Current CPC
Class: |
C23C 18/2013 20130101;
C23C 18/1662 20130101; C25D 5/56 20130101; C23C 18/1651
20130101 |
Class at
Publication: |
75/722 ;
205/109 |
International
Class: |
C25D 015/00 |
Claims
1. Novel ionic polymer metal composites manufactured by means of an
innovative chemical depositing process, the process comprising the
steps of: first depositing none noble metal salt cations inside a
cationic ionic polymer molecular network followed by chemical
reduction of the said none noble metal salt cations to generate
reduced none noble metal particles deposited inside the polymeric
molecular network and the outside surfaces of the polymeric
material, like outside metallic electrodes, followed by a second
electro or chemo deposition and plating of a noble metal inside and
on surfaces of the said reduced none noble metal particles in the
said polymer molecular network to protect the first said none noble
metal particles from oxidation, corrosion and chemical degradation
for prolonged sensing and actuation applications of the said novel
ionic polymer metal composite material which generates an
electrical signal with mechanical deformation and undergoes
mechanical deformation if an electric field is imposed on it.
2. The manufacturing processes for the novel ionic polymer metal
composite material of claim 1, further comprising the steps of:
first depositing none noble metal salt cations inside a cationic
polymer molecular network and the outside surfaces of the polymeric
material, like outside metallic electrodes, followed by chemical
reduction of the said none noble metal salt cations to generate
reduced none noble metal particles deposited inside the polymeric
network, followed by a second electro or chemo deposition and
plating of a noble metal inside and on surface of the said reduced
none noble metal particles in the said polymer molecular network to
protect the first said none noble metal particles from oxidation,
corrosion and chemical degradation for prolonged sensing and
actuation applications of the said novel ionic polymer metal
composite material which generates an electrical signal with
mechanical deformation and undergoes mechanical deformation if an
electric field is imposed on it.
3. The manufacturing processes for the novel ionic polymer metal
composite material of claim 1, as described in claims 1 and 2
further comprising the steps of: adding dispersing chemicals to the
said chemical reduction process, wherein said addition of a
dispersing agent prevents reduced noble and none noble metal
particles to coalesce and helps forming uniformly distributed none
noble metal particles chemically deposited inside the ionic polymer
network and further helps them to penetrate deeper into the said
ionic polymer molecular network.
4. The manufacturing processes for the novel ionic polymer metal
composite material of claim 1, as further described in claim 2
further comprising the steps of: adding an alcohol solvent to the
reduction solution, wherein said addition of an alcohol solvent
such as isopropyl alcohol and/or ethyl alcohol, helps expand the
ionic polymer network and enhances deeper penetration of noble and
none noble metal particles into said ionic polymer molecular
network.
5. The manufacturing processes for the novel ionic polymer metal
composite material of claim 1, as further described in claim 2
further comprising the steps of: mechanically stretching the said
ionic polymer before the start of manufacturing processes described
in claims 1, 2, 3 and 4, wherein said mechanical stretching helps
expand the ionic polymer network and enhances deeper penetration of
noble and none noble metal particles into said ionic polymer
molecular network.
6. The novel ionic polymer metal composite of claim 1 to be used as
electromechanical sensors in the sense that if they are
mechanically moved or deformed they generate an electrical voltage
across their surface electrodes. Typical values are that for a
cantilever sample of such active materials of dimensions 20
mm.times.5 mm.times.0.2 mm flipped at one end by 10 mm, generates
up to 10 mV across its surface electrodes.
7. The novel ionic polymer metal composite of claim 1 to be used as
electromechanical actuators, transducers and artificial muscles in
the sense that if they are electrically activated by placing an
electric field across their surface electrodes of the said
cantilever sample in claim 6 as a bending actuator, they move or
bend or flip dynamically like a wing with time varying electric
fields. Typical values are that a cantilever sample of such active
materials of dimensions 20 mm.times.5 mm.times.0.2 mm placed in an
electric field of 5 mV/.mu.m, generates a bending deflection of
about 10 mm at its free end.
8. The novel ionic polymer metal composite material of claim 1
further encapsulated inside a flexible polymeric membrane to keep
it hermetically sealed and moist and to provide additional outside
protection.
Description
BACKGROUND OF INVENTION
[0001] The present invention relates to novel electrically active
ionic polymer metal composite materials and novel methods of
manufacturing them.
[0002] The creation of ionic polymer metal composite materials made
from polymers and polyelectrolytes are relatively new but also
fairly well known.
[0003] U.S. Pat. No. 6,403,245, to Hunt, discloses that a
electro-catalyst is typically provided as a thin layer adjacent to
the ion-exchange membrane (see also U.S. Pat. Nos. 5,132,193 and
5,409,785). The electro-catalyst layer is typically applied as a
coating to one major surface of a sheet of porous, electrically
conductive sheet material or to one surface of the ion-exchange
membrane. The Phosphoric Acid Fuel Cells (PAFCs), which are the
most commercially developed fuel cells, typically use 90 ozs. of
platinum in a 500 kw unit, with 80-85% of the metal being
recoverable by recycling. With the development of PAFCs, the power
industry is poised to provide a source of fuel that is clean,
efficient, noiseless and abundant. For the applications, other
types of fuel cells, such as Proton Exchange Membrane Fuel Cells
(PEMFCs), pose a better solution. PEMFCs offer a technology that
has an acceptable power to weight ratio, and which is also clean,
efficient and noiseless. The electro-catalyst layers compromising
platinum and platinum-group elements, both for anode and cathode,
are presently a high-cost component of PEMFCs. Studies have shown
that the catalyst accounts for $2-3 of the total cost of
$15-21/kilowatt. Most of the fuel cell cost is related to the
membrane area via current collectors, seals, etc. Accordingly,
there is a desire to achieve cost reduction through higher catalyst
efficiency by increasing the power per unit area. Although PAFC
technology is well suited for use in power plant fuel cell
facilities, their high weight-to-power ratio makes PAFC technology
a poor fit for use in vehicles, such as zero-emission vehicles
(ZEVs), presently needed to reduce pollution in densely populated
areas.
[0004] U.S. Pat. No. 6,109,852, to Shahinpoor et al., discloses a
chemical coating and reduction, mechanical/electrical treatment of
ion-exchange materials to convert them to synthetic muscles. The
actuator of the invention showing the treated membrane actuator
with electrodes placed at one end of the membrane, the electrodes
being further attached to a power source. Synthetic muscles created
by the proposed method are capable of undergoing electrically
controllable large deformations resembling the behavior of
biological muscles. Plus, a metal salt deposit on membrane used a
noble metal palladium, nickel or platinum.
[0005] U.S. Pat. No. 5,389,222, to Shahinpoor discloses
electrically controllable polymeric gel actuators or synthetic
muscles, using gels made of polyvinyl alcohol, polyacrylic acid,
polyacrylonitrile, or polyacrylamide contained in an electrolytic
solvent bath. These actuators operate by reacting to changes in the
ionization of a surrounding electrolyte by expanding or
contracting, and can be spring-loaded and/or mechanically biased
for specific applications. Polymeric gel configurations such as
sheets, solid shapes or fiber aggregates are contemplated, as are
the use of a salt water solution for the electrolyte, and a
platinum catalyst in the actuator housing to recombine the hydrogen
and oxygen produced as a result of electrolysis during ionization
of the electrolyte. Again, liquid containment is required to
maintain strength and electric controllability, and not enough
deformation or displacement is generated.
[0006] U.S. Pat. No. 5,268,082, to Oguro et al., discloses an
actuator element based comprises an ion exchange membrane and a
pair of electrodes attached to opposite surfaces of the ion
exchange membrane; the ion exchange membrane in a water-containing
state being caused to bend and/or deform by application of an
electric potential difference thereacross.
[0007] U.S. Pat. No. 5,250,167, to Adolf, et al., discloses
actuators or synthetic muscles, using polymeric gels contained in
compliant containers with their solvents; these actuators undergo
substantial expansion and contraction when subjected to changing
environments. The actuators may be rigid or flexible and may be
computer-controlled. The driver may also be electrolytic, where
application of a voltage across the polymer gel causes a pH
gradient to evolve between the electrodes. For example, filling the
polymer fibers with platinum by alternatively treating them with
solutions of platinic chloride and sodium borohydride obtains a
reversible expansion and contraction of the fiber with the
application of an electric field. The actuating gel itself is the
only moving part required and the electric field may be only on the
order of a few volts per centimeter. The disadvantage is that
actuator performance is dictated by the parameters of the polymeric
gel used. Furthermore, liquid containment is required to make the
actuators stronger and not so easily broken.
[0008] U.S. Pat. No. 5,100,933, to Tanaka, et al., discloses the
use of ionized crosslinked polyacrylamide gels as engines or
synthetic muscles; the gels can contain a metal ion and are capable
of discontinuous volume changes induced by infinitesimal changes in
environment. The gel is made by dissolving acrylamide monomers and
bisacrylamide monomers in water, adding a polymerization initiator
(in particular, ammonium persulfate and TEMED, or
tetramethyl-ethylene-diamin-e) to the solution, soaking the gel
sample in water to wash away all residual monomers and initiators,
immersing the gel in a basic solution of TEMED for up to 60 days,
then immersing the gel in a solvent (in particular, acetone,
acetone in water, ethanol and water, or methanol and water). The
primary disadvantages of these actuators are generally that the
response time of the gel is much longer than that of other known
actuator components and that the gel must be contained in the
solvent bath. The gels are also mechanically brittle and easily
broken.
[0009] U.S. Pat. No. 4,522,698, to Maget, discloses a prime mover
that uses pressure increases and decreases induced by converting
molecules of electrochemically active material to ions,
transporting ions through an electrolytic membrane and reconverting
the ions to molecules. The prime mover includes gas-tight
compartments filled with an electrochemically active material and
separated by an electrolytic membrane, such as an ion-exchange
membrane, that incorporates electrodes so that a voltage gradient
can be established across the membrane to induce current flow
through the membrane. When the current flows through the membrane,
molecules travel through the membrane and are reconverted to
molecules in the opposite compartment causing a pressure increase
in the receiving compartment and a pressure decrease in the other
compartment. The pressure changes are converted to mechanical
motion that can be used as a driver for a mechanical load. The
disadvantages of this technique are that the resulting motion is
small and the pressure increase may rupture the membrane.
[0010] U.S. Pat. No. 4,364,803, to Nidola et al., discloses a
process for deposition of catalytic electrodes on ion-exchange
membranes and an electrolytic cell made by the process. The process
involves contacting a water-swollen, roughened membrane with an
amphoteric organic or metal salt thereof, such as alkali metal
salts thereof, e.g., platinum, palladium, and nickel. After further
processing, the membrane is then contacted with a solution of the
selected metal salt wherein sorption of the metal salts takes place
mainly on the membrane surface in the vicinity of the polar groups
of the polymer or the pre-adsorbed polar groups of the amphoteric
organic. The absorbed/adsorbed metal creates the catalytic
electrodes. The patent discloses operation of the electrode in the
presence of sodium brine/caustic soda.
[0011] "Development of a Novel Electrochemically Active Membrane
and Smart Material Based Vibration Sensor/Damper," by Sadeghipour
et al., Smart Materials and Structures, Vol. 1, pp. 172-179,
(1992), discloses "smart" materials developed from metalized NAFION
membranes that may be used for vibration sensing and damping
applications. For sensing applications, the smart NAFION based
viscoelastic material generates a voltage response when subject to
mechanical vibrations. For damping applications, the material
dissipates mechanical or pressure induced voltage potentials
(electrical energy) as heat energy. The article also discloses a
method of making the smart materials comprising steps of platinum
deposition onto a NAFION, membrane and saturation of the platinum
coated metal with hydrogen under high pressure, or alternatively,
exposing the platinum coated membrane to dissolved hydrogen.
Applications for the smart material include integration into
cantilever structures, such as robot arms, aircraft wings, etc.,
for damping; use as a vibration cell accelerometer; and use as a
pressure cell. For vibration cell sensors, the authors reported
voltage response over the frequency range of approximately 100 Hz
to approximately 3000 Hz. Load response was also reported at 500 Hz
and 1000 Hz. A plot of simulated tip deflection versus time for an
electrically damped metal-NAFION composite beam were reported for
initial positive tip deflections of 1% of beam length. Because no
beam lengths were given, the magnitude of displacement cannot be
determined.
[0012] Therefore, the above review of the pertinent literature
clearly indicates that current electrically active ionic polymer
metal composite materials manufacturing processes and materials
cost are expensive due to exclusive use of noble metal salts such
as platinum, palladium and gold as penetrating metal particles.
Further, such noble metals do no provide highly conductive metal
particles, which are desirable, such as silver and copper, into the
ionic network. Thus, there is an existing need for novel materials
and methods of manufacturing electrically active ionic polymer
metal composite materials to be cost effective and economical for
mass production. Thus, in this disclosure we introduce a unique
electro or chemo deposition and chemical plating methodology to
chemically deposit highly conductive none noble metal particles in
the ionic polymeric network first and then electrically or
chemically plate the none noble metal particles with noble metals.
In this manner we embed in the ionic polymer first a highly
electrically conductive phase of none noble metal particles first,
which is highly desirable for sensing and actuation properties of
these electrically active ionic polymer metal composites or IPMC"s
and then we electroplate or chemo plate the none noble metal
particles with a noble metal such as Gold or platinum.
SUMMARY OF INVENTION
[0013] This invention describes novel electrically active ionic
polymer metal composite materials and novel methods of
manufacturing them by means of a series of innovative chemical
processes of first chemically depositing none noble metal salt
cations inside a cationic polymer molecular network followed by
chemical reduction of the said none noble metal salt cations to
generate reduced none noble metal particles deposited inside the
polymeric molecular network followed by a second electro or chemo
deposition and plating of a noble metal inside and on the surfaces
of the reduced none noble metallic particles in the said polymer
molecular network to protect the first said none noble metal
particles from oxidation, corrosion and chemical degradation for
prolonged sensing and actuation applications of the said novel
ionic polymer metal composite material which generates an
electrical signal with mechanical deformation and undergoes
mechanical deformation if an electric field is imposed on it.
BRIEF DESCRIPTION OF DRAWINGS
[0014] The accompanying Figures, which are incorporated into and
form a part of the specification, illustrate several embodiments of
the present invention and, together with the description, serve to
explain the principles of the invention. However, these Figures, as
well as the following detailed description and the examples are
only for the purpose of illustrating a preferred embodiment of the
invention and are not to be construed as limiting the invention. In
the drawings:
[0015] FIG. 1 is a perspective view of a none noble metal ionic
polymer molecular network with surface Gold.
[0016] FIG. 2 is a perspective view of the ionic polymer molecular
network with none noble metal deposition showing the dendritic
penetration of said none noble metal into ionic polymer molecular
network as well as the Gold surface plating on top.
[0017] FIG. 3 is a perspective view of the none noble metal ionic
polymer composite with its Gold plated roughened surface.
DETAILED DESCRIPTION
[0018] This invention describes first novel ionic polymer metal
composites manufactured by means of an innovative chemical
depositing process, the process comprising the steps of: first
depositing none noble metal salt cations inside a cationic polymer
molecular network followed by chemical reduction of the said none
noble metal salt cations to generate reduced none noble metal
particles deposited inside the polymeric molecular network and the
outside surfaces of the polymeric material, like outside metallic
electrodes, followed by a second electro or chemo deposition and
plating of a noble metal inside and on surfaces of the said reduced
none noble metal particles in the said polymer molecular network to
protect the first said none noble metal particles from oxidation,
corrosion and chemical degradation for prolonged sensing and
actuation applications of the said novel ionic polymer metal
composite material which generates an electrical signal with
mechanical deformation and undergoes mechanical deformation if an
electric field is imposed on it.
[0019] The invention further describes the manufacturing processes
for the novel ionic polymer metal composite materials, further
comprising the steps of: adding dispersing chemicals to the said
chemical reduction process, wherein said addition of a dispersing
agent prevents reduced noble and none noble metal particles to
coalesce and helps forming uniformly distributed none noble metal
particles chemically deposited inside the ionic polymer network and
further helps them to penetrate deeper into the said ionic polymer
molecular network.
[0020] The invention further describes the manufacturing processes
for the novel ionic polymer metal composite materials, further
comprising the steps of: adding an alcohol solvent to the reduction
solution, wherein said addition of an alcohol solvent such as
isopropyl and ethyl alcohol, help expand the ionic polymer network
and enhances deeper penetration of none noble and noble metal
particles into said ionic polymer molecular network.
[0021] The invention further describes the manufacturing processes
for the novel ionic polymer metal composite materials, further
comprising the steps of: mechanically stretching the said ionic
polymer before the start of manufacturing processes, wherein said
mechanical stretching helps expand the ionic polymer network and
enhances deeper penetration of none noble and noble metal particles
into said ionic polymer molecular network.
[0022] The invention further describes yet a family of novel ionic
polymer metal composites to be used as electromechanical sensors in
the sense that if they are mechanically moved or deformed they
generate an electrical voltage across their surface electrodes.
Typical values are that for a cantilever sample of such active
materials of dimensions 20 mm.times.5 mm.times.0.2 mm flipped atone
end by 10 mm, generates up to 10 mV across its surface
electrodes.
[0023] The invention further describes yet another family of novel
ionic polymer metal composites to be used as electromechanical
actuators, transducers and artificial muscles in the sense that if
they are electrically activated by placing an electric field across
their surface electrodes of a cantilever sample in a bending
actuator configuration, they move or bend or flip dynamically like
a wing with time varying electric fields. Typical values are that a
cantilever sample of such active materials of dimensions 20
mm.times.5 mm.times.0.2 mm placed in an electric field of 5
mV/.mu.m generates a bending deflection of about 10 mm at its free
end.
[0024] The invention finally describes means of encapsulating the
novel ionic polymer metal composite materials inside a flexible
polymeric membrane to keep it hermetically sealed and moist and to
provide additional outside protection.
[0025] None noble metal manufacturing of ionic polymers results in
sensors, actuators, and synthetic muscles with enhanced overall
sensitivity and actuation response compared with noble metal
manufacturing.
[0026] In another preferred embodiment of the present invention,
dispersing agents are used create a more uniform distribution of
reduced metallic particles both for none noble and noble metal
particles deposited inside on the molecular network and on the
surfaces of the ionic polymer.; Some of the dispersing agents used
are polyvinylpyrrolidone; poly(1-vinylpyrrolidone-co-vinyl
acetate); poly(1-vinylpyrrolidone-co-2-dimethylamino ethyl
methacrylate).
[0027] Several preferred embodiments of the present invention can
be encapsulated with an impermeable flexible outer membrane to keep
the ionic polymer metal composite moist and prevent it from drying
up.
[0028] The novel material and the novel methods of manufacturing
them in this invention also have applications in such as making
membrane electrode assemblies (fuel cells), ionic exchange membrane
metal deposit, sensors, actuators, transducers and synthetic
muscles. The limitations associated with existing ionic polymer
metal composites materials and the methods for their manufacture
are overcome by the present invention which provides novel methods
of manufacturing and novel materials that are electrically active
ionic polymer metal composites.
[0029] Although the present invention has been described in terms
of the presently preferred embodiments, it is to be understood that
the disclosure is not to be interpreted as limiting. Various
alterations and modifications will no doubt become apparent to
those skilled in the art after having read the above disclosure.
Accordingly, it is intended that the appended claims be interpreted
as covering all alterations and modifications as fall within the
true spirit and scope of the invention.
* * * * *