AbstractPolymeric films were deposited on Al2O3ceramic substrates by plasma deposition from trimethylsilyldimethylamine (TMSDMA) and bis(dimethylamino)methylvinylsilane (BDMAMVS), and their capacitance‐relative humidity characteristics investigated. Films doped with methylbromide showed a linear dependence of log(capacitance) with relative humidity over the range 20–90% suggesting application on a moisture sensor device. Hysterisis effects were negligible and the response time was within 1