A novel non-fragile carbon nanoparticle-PMMA conductive composite vapor sensor with high sensitivity and rapid response

Abstract

Novel non-fragile porous conductive nanocomposite vapor sensors with variant volume porosities and specific surface areas have been fabricated from PMMA and carbon nanoparticles. Sensing films were obtained by well known drycast non-solvent induced phase separation (NIPS) method. Porous composite structures have been characterized by SEM, BET and water evaporation methods. Response behavior of fabricated porous sensors toward various organic vapors in different concentrations were measured and compared to response of their conventional dense counterparts in dynamic mode. Both sensitivity and response speed of vapor sensors have been improved remarkably with introducing porosity to the sensing layer. Similar results were observed when nano-sized carbon black as conductive filler in composite was replaced with multiwall carbon nanotube. Improved characteristics of the sensor response were related to better sorption properties of sensing film due to increased porosity and specific surface area obtained by this method of thin film preparation. These porous sensitive layers showed non-fragility that particularly will be promising in fabrication of wearable sensors. Simplicity and versatility of both fabrication method and sensing mechanism of these porous conductive composite vapor sensors make them advantageous wherever sensing materials with low cost and high performance needed. ©2009 IEEE.