UV Resistant Poly(3,4-ethylenedioxythiophene) Thin Films: Layer-by-Layer Assembly with Absorbing Nanoparticles

摘要

Layer-by-layer (LbL) assembly is used to create thin films by alternately exposing a substrate to positively- and negatively-charged molecules or particles in water. In recent years, LbL assemblies containing poly(3,4-ethylenedioxythiophene) (PEDOT) have been heavily studied, but little work has focused on improving the environmental stability of these thin films. Most intrinsically conductive polymers suffer from increasing resistance with exposure to ultraviolet light. Films made by alternately depositing poly(styrene sulfonate)-doped PEDOT and polyethylenimine (PEI) show an order of magnitude increase in sheet resistance after just 28 hours of exposure to 365 nm light, but this degradation is significantly diminished when TiO_2 nanoparticles are included in the PEI layers.