Development of Humidity Sensors using Layer-by-Layer nanoAssembly of Polypyrrole

Abstract

AbstractIn this paper we demonstrate high sensitive and fast response humidity sensors using layer-by-layer (LbL) nano-assembled films of Polypyrrole (PPY). Spin coated PPY films were used for sensitivity and response time comparisons. The change in electrical sheet resistance of the sensing films was monitored as the device was exposed to humidity. For 5% change in relative humidity sensitivity measured from layer-by-layer based devices was 10% and 8% for the spin coated devices. The response time for LbL based and spin coated device was measured as 25 seconds and 57 seconds respectively. The LbL nano-assembled films of PPY showed the better response in terms of sensitivity, response time, linearity and degradation. An intended application for these LbL nano-assembled devices is in disposable handheld instruments to monitor the presence of humidity in humidity sensitive environments.