Abstract
We have successfully demonstrated the fabrication of piezoelectric PDMS electrets utilizing foam forming and micro plasma discharge processes. To acquire electromechanical sensitivity, PDMS foams with micrometer-sized closed cells are implanted with positive and negative charges on the opposite internal surfaces of each cell, which behaves just like a dipole. In the prototype demonstration, PDMS foams with nanoparticles or polymers coated internally are fabricated and charged under electric fields up to 30 MV/m. The resulting PDMS electrets show an elastic modulus of 370 kPa and a piezoelectric coefficient (d33) up to 106 pC/N, which is more than 5 times higher than that of common piezoelectric polymers (e.g., PVDF). As such, the demonstrated piezoelectric PDMS electrets could serve as soft and sensitive electromechanical transducers, which are desired for a variety of MEMS applications. ©2010 IEEE.