Patent ID: 7785704
Filing Date: 2010-08-31
Classification: G01D,G01L,Y10T

Abstract:
1. A pressure sensitive device configured to function as a pressure or force sensor, comprising: a nonconducting supporting substrate; and a pressure sensitive material supported by the substrate, comprising conductive carbon nanoparticles dispersed in a polymeric matrix comprising a product of a polycondensation reaction of a dianhydride and a diamine, wherein the dianhydride is selected from the group consisting of pyromellitic dianhydride, 1,2,4,5 tetracarboxylic benzene dianhydride, 3,4,3′,4′-benzophenone tetracarboxylic dianhydride, 3,4,3′,4′-biphenyl tetracarboxylic dianhydride, terphenyl tetracarboxylic dianhydride, 3,3′,4,4′-oxydiphthalic dianhydride, 2,2′-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride, 3,3′,4,4′-diphenylsulfone tetracarboxylic dianhydride, bis(3,4-dicarboxyphenyl)dimethylsilane dianhydride, 4,4′-(2,2,2-trifluoro-1-phenylethylidene)diphthalic anhydride, 5,5′-[2,2,2-trifluoro-1-(trifluoromethyl)ethylidene]bis-1,3-isobenzenefurandione, 3,4,3′,4′-biphenyltetracarboxylic benzene dianhydride, or combinations thereof, and wherein the diamine is selected from the group consisting of 4,4′-oxydiamine, 4,4′-diamino diphenyl, 4 amino phenyl ether, 4,4′-methylenedianiline, 4,4′-diamino diphenyl methane, meta-phenyl diamine, 1,3-phenylene diamine, 1,4-phenylene diamine, isophorone diamine, (1,1′-biphenyl)-4,4′-diamine, durene diamine, 2,3,5,6-tetramethylphenylenediamine, 1,3-bis(3-aminophenoxy)benzene, 1,3-bis(4-aminophenoxy)benzene, or combinations thereof; and wherein the pressure sensitive material has a conductivity falling within a range of about 0.01 μS/cm to about 1300 μS/cm and a sensitivity falling within a range of about 0.01 μS/lb to about 300 μS/lb over the entire temperature range of about −50° F. to about 350° F.