Chemical sensing based on double layer PHEMA polymer and platinum nanoparticle films

Chemical gas sensors have been fabricated from platinum and poly(2-hydroxyethylmethacrylate) (PHEMA) polymer. Sputtered platinum nanoparticles have been deposited on flat silicon substrates and a second layer of PHEMA polymer has been deposited on top using ink-jet printing. Density of the platinum nanoparticles and resistance of the device, which can both be tuned by controlling the deposition time, directly affect the response of the sensors as measured in the presence of ethanol and humidity. Chemi-resistive and chemi-capacitive sensors capable of detecting low gas concentrations (1000 ppm of humidity and 500 ppm of ethanol) have been made possible.