A humidity sensor based on interpenetrating polymer network prepared from poly(dimethylaminoethyl methacrylate) and poly(glycidyl methacrylate)

Humidity sensitive polymeric thin films with an interpenetrating network (IPN) structure were prepared by cross-linking reactions of poly(dimethylaminoethyl methacrylate) and poly(glycidyl methacrylate) with 1,4-dibromobutane (DBB) and diethyltriamine (DETA) as cross-linking agents, respectively. The humidity sensors so prepared showed a high sensitivity over a wide range of relative humidity (RH) (20–97%RH) and a small hysteresis (∼2%RH). The response time for adsorption and desorption process between 22 and 84%RH was 4 and 20 s, respectively, indicating a fast response. The effects of the concentration of polymers, molar ratio of cross-linking agents and polymers and aging time of the precursor solution for dip-coating on their humidity sensitive properties were investigated.