Water-resistive humidity sensor prepared from new polyelectrolyte containing both photo-curable 4-styrylpyridinium function and thiol anchor

摘要

A simple strategy was developed based on a new monomer, 2-[4-[2-(4-pyridyl)vinyl]phenoxy]ethyl methacrylate (PVPEM), comprising 4-styrylpyridine to obtain both photocurable and attachable polyelectrolyte to a gold electrode. Humidity-sensing membranes are composed of copolymers of [2-(methacryloyloxy)ethyl] dimethyl propyl ammonium bromide (MEPAB), PVPEM and methyl-methacrylate, followed by thiolation. The purpose was to crosslink and to anchor the polyelectrolyte to the gold electrode. Polyelectrolyte inks were formulated. The resulting sensors which used printing methods reduced the deflection of sensor characteristics showing a humidity precision ±0.9%RH. The humidity sensor with copolymer MEPAB/PVPEM/MMA=60/10/30 showed a good sensitivity changing the resistance approximately four orders of magnitude including relative humidity varying from 20 to 95%RH and also a fast response and recovery time. The resultant sensors showed a good linearity and small hysteresis. The reliability including water resistance and a long-term stability were estimated for the application of the flexible humidity sensor.