Functionalized mesoporous silica films for gas sensing applications

Mesoporous silica films prepared by sol gel process and argon plasma calcination have been used to form hybrids for gas sensing applications by entrapping sensitive materials in the porous network. Plasma calcination, a low temperature process, is employed to gel the sol instead of conventional thermal calcination. Polymers and surfactants are used as templates for generating the mesoporous structure upon removal by the plasma calcination. TEM, EDX and FT-IR are used to characterize the obtained films. To demonstrate the gas sensing property of the functionalized silica films, 10 MHz Quartz Crystal Microbalance (QCM) coated with beta-cyclodextrin (beta-CD) functionalized silica film is tested as a sensor for benzene vapor detection. The higher surface area of the mesoporous silica films could accommodate more receptor molecules (beta-CD molecules) and subsequently more target analytes that enhance the QCM response. The sensitivity of the QCM is enhanced by depositing plasma calcined mesoporous sensing films on the electrodes.