Functionalized mesoporous silica films for gas sensing applications

Abstract

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 β-cyclodextrin (β-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 (β-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.

Electroanalytical Applications of Microporous Zeolites and Mesoporous (Organo)Silicas: Recent Trends

“…Metal-insulator-semiconductor devices comprising a mesoporous silica film were applied to gaseous NO and NOx sensing in a detection mode based on surface photovoltage [204,247,248]. Other promising avenues rely on the resort to functionalized films (i.e., with cyclodextrins [249,250]), as applied to the detection of benzene and ethanol vapors using quartz crystal microbalance, but this approach has still to be developed in electrochemistry.…”

Mesoporous Silicate Materials in Sensing

“…Benzene detection has been facilitated through interrogation by FTIR of SBA-15 and SBA-16 materials [123]. Other techniques such as measurement of refractive index changes in synthetic mesoporous opals [124] and quartz crystal microbalance using thin films of mesoporous materials have also proven successful [104, 125, 126]. Detection of other common solvents such as toluene and cyclohexane using mesoporous materials has also been reported [90, 127-129].…”

“…Further grafting using hexamethyldisilazane resulted in a material with stable fluorescence emission that could be applied to the detection of polar organic vapors such as acetone and methanol [129]. Fluorescence emission of coumarin 485 encapsulated in a mesoporous material, conductance measurements on mesoporous thin films, and quartz crystal microbalance measurements based on mesoporous materials have also been applied to the sensing of alcohols [104, 125, 126, 131, 132]. Thiols and phosphines have been detected using surface plasmon reasonance techniques employing gold nanoparticles supported in a mesoporous thin film [133, 134].…”

Template Based Synthesis of Mesoporous Silica Material and Its Application in Removal of Fluorescent Dyes

“…Since the discovery of mesoporous silica in 1992, it has received enormous interest due to their applications in catalysis 1 2 drug delivery, [3][4][5] sensors, 6 antireflective coatings, 7 gas sorption 8 and separation. 9-10 Mesoporous silica nanoparticles have been used to catalyze the formation of conductive polymers within their pores.…”