Water-resistive humidity sensor prepared by printing process using polyelectrolyte ink derived from new monomer.
A simple strategy was developed based on a new monomer containing both photocurable function and ammonium salt, N-(2-cinnamoyloxy)ethyl-N-(2-(methacryloyloxy)ethyl)-N,N-dimethyl ammonium bromide (CMDAB) to obtain photocurable polyelectrolyte ink and stable humidity-sensitive membranes by printing process. Humidity-sensitive membranes are photocrosslinked polyelectrolytes obtained from copolymers of [2-(methacryloyloxy)ethyl] dimethyl propyl ammonium bromide (MEPAB), CMDAB and MMA. A flexible gold electrode/polyimide was pretreated with 2-(mercaptoethyl) cinnamamide (MEC) containing a thiol-coupling agent for the purpose of anchoring the humidity-sensitive polyelectrolyte to the gold electrode. The sensors using screen printing methods reduced the deflection of sensor characteristics showing humidity precision ±1%RH. The photocured copolymer MEPAB/CMDAB/MMA = 63/7/30 show good sensitivity (0.0586 logΩ/%RH) changing resistance approximately four orders of magnitude with relative humidity varying from 20% to 95% and fast response and recovery time. The resultant sensors showed acceptable linearity (Y = -0.04X + 7.0, R(2) = -0.9900) and small hysteresis. The reliability including water resistance and a long-term stability were estimated for the application of the flexible humidity sensor prepared by screen printing process.
Department of Nanobiomedical Science and WCU Research Center of Nanobiomedical Science, Dankook University, Cheonan, Chungnam 330-714, Korea.
Min-Ji
MJ
Kim
Myoung-Seon
MS
Gong
D002934:Cinnamates / Q000737:chemistry; D004566:Electrodes; D004573:Electrolytes / Q000737:chemistry*; D006046:Gold / Q000737:chemistry; D007281:Ink; D015394:Molecular Structure; D011108:Polymers / Q000737:chemistry*; D011327:Printing / Q000379:methods*; D012680:Sensitivity and Specificity; D013438:Sulfhydryl Compounds / Q000737:chemistry; D013499:Surface Properties; D014867:Water / Q000737:chemistry*
D002934:Cinnamates; D004573:Electrolytes; D011108:Polymers; D013438:Sulfhydryl Compounds; D014867:Water; D006046:Gold