Effective Dielectric Constant of PVDF Graft Copolymer for Enhancing Triboelectric Nanogenerator

Abstract

environment, such as wind, solar and geothermal, have attracted increasing attention in the past decade due to the energy crisis and global warming. Generally, mechanical energy converted into electricity, namely, by using electromagnetic, electrostatic, and piezoelectric effects. Most recently, a new type of power generating device, named as triboelectric nanogenerator (TENG) based on triboelectric effects coupled with electrostatic effects have been demonstrated as powerful means of harvesting mechanical energy from living environment. Here, the Atom transfer radical polymerization (ATRP) technique of poly(tert-butyl acrylate) (PtBA) was successfully applied to control dielectric properties into PVDF films using PVDF containing secondary fluoride groups as macroinitiator and tune their electrical properties. We report a new PVDF graft copolymer based TENG for effective dielectrics, which has various tBA mole fractions of 0, 10, 15, 18 % controlled by reaction times, resulting in 2 times higher output voltage and current density of 68 V and 19 μA/cm2 at PVDF-G18 based TENG, compared to general PVDF based TENG due to the increase of dielectric constant of negatively charged layer and surface potential on the triboelectric surfaces. Therefore, the ATRP synthesis strategy shows a great promise in controlling dielectric properties of negatively charged layer in TENG and tuning the performance of polymer-based triboelectric devices for effective mechanical energy harvesting.