PIEZOELECTRIC CAPACITOR WITH CO-PLANAR PATTERNED ELECTRODES
A piezoelectric capacitor is designed with A) a composite article that has: 1) a first dry piezoelectric layer; and 2) a first pair of non-electrically-connected co-planar patterned electrodes that are arranged contiguously with at least one opposing surface of the dry piezoelectric layer. At least one of the non-electrically-connected co-planar patterned electrodes has (a) an electrically-conductive material; and (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%. The piezoelectric capacitor also has B) electrical communication means attached to each of the first pair of non-electrically-connected co-planar patterned electrodes for electrical communication of the composite article with an external circuit.
1 . A piezoelectric capacitor comprising:
A) a composite article comprising:
1) a first dry piezoelectric layer (first dry PL) comprising a piezoelectric material and having first and second opposing surfaces; and
2) a first pair of non-electrically-connected co-planar patterned electrodes that are arranged contiguously with at least one of the first and second opposing surfaces of the first dry PL, at least one of the first pair of non-electrically-connected co-planar patterned electrodes consisting 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 μm and up to and including 500 μm and a polydispersity coefficient that is less than or each to 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 each of the first pair of non-electrically-connected co-planar patterned electrodes is arranged adjacent to an insulating substrate, it exhibits a resistivity of less than 10,000 ohms-cm; and
B) electrical communication means attached to each of the first pair of non-electrically-connected co-planar patterned electrodes for electrical communication of the composite article with an external circuit, and
optionally, each of the non-electrically-connected co-planar patterned electrodes 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 piezoelectric capacitor of claim 1 , further comprising one or more additional pairs of non-electrically-connected co-planar patterned electrodes that are arranged contiguously with the same opposing surface of the first dry PL as the first pair of non-electrically-connected co-planar patterned electrodes.
3 . The piezoelectric capacitor of claim 1 , wherein the first pair of non-electrically-connected co-planar patterned electrodes is arranged contiguously on the first opposing surface of the first dry PL, and
the piezoelectric capacitor further comprises:
either a dry electrically-conductive layer containing (b) particles (dry ECL-P) or a dry dielectric layer containing (b) particles (dry DL-P) arranged contiguously on the second opposing surface of the first dry PL,
a second dry piezoelectric layer (second dry PL) having first and second opposing surfaces, the second dry PL being arranged on its first opposing surface contiguously with either the dry ECL-P or dry DL-P, and
a second pair of non-electrically-connected co-planar patterned electrodes that are arranged contiguously with the second opposing surface of the second dry PL.
4 . The piezoelectric capacitor of claim 3 , further comprising one or more additional pairs of non-electrically-connected co-planar patterned electrodes that are arranged contiguously with the second opposing surface of the second dry PL.
5 . The piezoelectric capacitor of claim 1 , wherein the (b) particles are composed of one or more polymeric materials.
6 . The piezoelectric capacitor of claim 1 , wherein the (b) particles are composed of one or more inorganic materials.
7 . The piezoelectric capacitor of claim 1 , wherein the (c) binder material is present in the first pair of non-electrically-connected co-planar patterned electrodes, and comprises one or more polyurethanes, acrylate polymers, polyvinyl acetals, or polyacrylate precursors to an acrylate polymer.
8 . The piezoelectric capacitor of claim 1 , wherein the (c) binder material is present in each of the first pair of the non-electrically-connected co-planar patterned electrodes in an amount of at least 0.1 weight % and up to and including 10 weight %, based on the total weight of each of the first pair of the non-electrically-connected co-planar patterned electrodes.
9 . The piezoelectric capacitor of claim 1 , wherein the (b) particles have a polydispersity coefficient that is less than or equal to 1.5.
10 . The piezoelectric capacitor of claim 1 , wherein the (b) particles have a polydispersity coefficient that is less than or equal to 1.25.
11 . The piezoelectric capacitor of claim 1 , wherein the first dry PL comprises beta phase polyvinylidene fluoride.
12 . The piezoelectric capacitor of claim 1 , wherein the first dry PL comprises a single crystalline or polycrystalline ceramic.
13 . The piezoelectric capacitor of claim 1 , wherein the (a) electrically-conductive material consists essentially of electrically-conductive silver nanoperticles.