Multilayer polymer composites containing alternating layers of polycarbonate (PC) and polyvinylidene fluoride (PVDF) show great promise as the active dielectric material in high energy density capacitors. The dielectric strength of these films is increased relative to monolithic PC or PVDF because the interfaces serve as barriers to the propagation of an electrical breakdown. The energy density of the film is proportional to the square of the applied field. First generation PC/PVDF multilayer films show breakdown strength (EB) greater than 750 V/μm under divergent field conditions and energy densities (Ud) as high as 13 J/cm3. To further increase the dielectric strength and energy density, we have prepared two new types of interface-modified structures: graded permittivity multilayer composites and enhanced adhesion multilayer composites. Both types of composites contain thin interfacial layers positioned between the discrete layers of PC and PVDF, designed to take advantage of subsequent changes in the dielectric or mechanical properties of the film. These composites show increased dielectric strength (EB = 900 V/μm under divergent field conditions and EB = 760 V/μm under homogeneous field conditions) and energy density (Ud = 16 J/cm3) relative to standard multilayer films without interface modification. The talk will also focus on structure and failure analysis on interface-modified films using advanced imaging techniques such as AFM, TEM, and FIB/SEM.

Interface-modified multilayer polymer films for high energy density capacitors

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.