US Patent 7785704 High temperature pressure sensitive devices and methods thereof

A pressure sensitive device that provides a stable response to measure an applied force at temperatures greater than 150° F. (about 66° C.) is disclosed. The pressure sensitive device can have a conductivity of about 0.01 μS to about 1300 μS and a sensitivity of about 0.01 μS/lb to about 300 μS/lb (about 0.02 μS/kg to about 660 μS/kg) at about a temperature range of about −50° F. to over about 400° F. or 420° F. (about −45° C. to over about 205° C. or 216° C.). The pressure sensitive device can have a substrate of polyimide, conductive leads of silver dispersed in a polyhydroxy ether crosslinked with melamine formaldehyde, and a pressure sensitive layer of carbon nanoparticles dispersed in cured polyamic acid forming a polyimide.