Spray coating of polymer electret with polystyrene nanoparticles for electrostatic energy harvesting

A spray-coating method for cyclic olefin copolymer (COC) electret material with polystyrene (PS) nanoparticles is developed here. Compared with the traditional polymer electret materials, the COC electrets with PS nanoparticles achieved better surface charge stability when exposed to harsh environment at high humidity or high temperature. With the spray coating technique, they can easily control the thickness of the electret layer. The surface charge stability of the electret has been detailed studied with various concentrations of the nanoparticles. They have also applied the spray coated electret to electrostatic energy harvesting devices. The experiments confirmed that the energy harvesting devices can generate more stable power output using the spray coated electret with nanoparticles.