Remarkable humidity-responsive sensor based on poly (N,N-diethylaminoethyl methacrylate)-b-polystyrene block copolymers

We report on the synthesis and characterization of Poly (N,N-diethylaminoethyl methacrylate)-block-Polystyrene (PDEAEMA-b-PS) di-block copolymer. The synthesis was finished by using reversible addition-fragmentation chain transfer (RAFT) polymerization method. The investigation results of humidity sensing property of pure PDEAEMA, pure PS and PDEAEMA-b-PS di-block copolymer demonstrated that the block copolymer shown the best sensing performance. Its impedance changed more than three orders of magnitude in the range from 22% to 95% relative humidity. The hysteresis was less than 8% RH, the response and recovery time was 60 and 206 s, respectively. The humidity sensing mechanism was discussed based on complex impedance plots. This work broadens the responsive scope of PDEAEMA-based materials from double-responsive (pH and temperature) to multi-responsive (pH, temperature and humidity).