METHOD FOR PROVIDING PIEZOELECTRIC DEVICES
A piezoelectric device can be provided by: A) providing a first dry piezoelectric layer (first dry PL) comprising a dielectric material and having first and second opposing surfaces; and B) providing a first dry electrically-conductive layer (first dry ECL-P) that is arranged contiguously with the first opposing surface of the first dry PL. The first dry ECL-P has (a) an electrically-conductive material; and (b) particles distributed within the (a) electrically-conductive material, the (b) particles having a Young's modulus that is different from the Young's modulus of the (a) electrically-conductive material by at least 10%, and which (b) particles have a d50 of at least 500 nm and up to and including 500 μm and a polydispersity coefficient that is less than 3. The weight ratio of the (b) particles to the (a) electrically-conductive material is at least 0.01:1 and up to and including 10:1.
1 . A method for providing a piezoelectric device, comprising:
A) providing a first dry piezoelectric layer (first dry PL) comprising a dielectric material and having first and second opposing surfaces; and
B) providing a first dry electrically-conductive layer (first dry ECL-P) that is arranged contiguously with the first opposing surface of the first dry PL, wherein the first dry ECL-P consists essentially of:
(a) an electrically-conductive material; and
(b) particles distributed within the (a) electrically-conductive material, the (b) particles having a Young's modulus that is different from the Young's modulus of the (a) electrically-conductive material by at least 10%, and which (b) particles have a d50 of at least 500 nm and up to and including 500 μm and a polydispersity coefficient that is less than 3;
provided that:
the weight ratio of the (b) particles to the (a) electrically-conductive material is at least 0.01:1 and up to and including 10:1, and
when the first dry ECL-P is arranged adjacent to an insulating substrate, it exhibits a resistivity of less than 10,000 ohms-cm, and
optionally, the first dry ECL-P further includes (c) a binder material that is non-electrically-conductive and has a weight average molecular weight of at least 5,000.
2 . The method of claim 1 , wherein the first dry ECL-P is provided by applying a composition (EC-P composition) to the first opposing surface of the first dry PL, the ECP composition consisting essentially of:
the (a) electrically-conductive material; and
the (b) particles; and
optionally, the EC-P composition includes the (c) a binder material; and (d) a solvent medium.
3 . The method of claim 2 wherein, the EC-P composition is applied to the first opposing surface of the dry PL in a patternwise fashion using screen printing, curtain coating, gravure printing, stenciling, or airbrushing.
4 . The method of claim 1 , wherein the first dry PL is disposed on an insulative substrate.
5 . The method of claim 1 , wherein the first dry PL is disposed on a transparent flexible substrate.
6 . The method of claim 1 , wherein the first dry PL is disposed on a continuous web of a transparent flexible substrate in a patternwise fashion using flexographic printing.
7 . The method of claim 1 , wherein the first dry PL is disposed on an electrically-conductive substrate.
8 . The method of claim 1 , wherein the (b) particles are composed of one or more polymeric materials.
9 . The method of claim 1 , wherein the (b) particles are composed of one or more inorganic materials.
10 . The method of claim 1 , wherein the (c) binder material is present in the EC-P composition, which (c) binder material comprises one or more polyurethanes, acrylate polymers, polyvinyl acetals, or polyacrylate precursors to an acrylate polymer.
11 . The method of claim 1 , wherein the (c) binder material is present in the first dry ECL-P in an amount of at least 0.1 weight % and up to and including 10 weight %, based on the total weight of the first ECL-P.
12 . The method of claim 1 , wherein the (b) particles have a polydispersity coefficient that is less than or equal to 1.5.
13 . The method of claim 1 , wherein the (b) particles have a polydispersity coefficient that is less than or equal to 1.25.
14 . The method of claim 1 , wherein the first dry PL comprises beta phase polyvinylidene fluoride.
15 . The method of claim 1 , wherein the first dry PL comprises a single crystalline or polycrystalline ceramic.
16 . The method of claim 1 , wherein the (a) electrically-conductive material consists essentially of electrically-conductive silver nanoparticles.
17 . The method of claim 1 , further comprising providing a second dry piezoelectric layer (second dry PL) comprising a piezoelectric material on the first dry ECL-P.