Guided SH-SAW toluene sensors with mesoporous silica sensitive coatings: Increased sensitivity through mesostructuration control

摘要

Thanks to high specific surface areas, mesoporous silica films have been considered as sensitive coatings for guided shear-horizontal surface acoustic wave toluene sensors. In order to increase their sensitivity, the influence on toluene detection of the structuring agent used in the evaporation-induced-self-assembly fabrication process of these inorganic films has been studied. In this paper, F127 block copolymer is compared to cethyltrimethylammonium bromide (CTAB). Sensors coated with 100 nm thick films structured with CTAB show an average sensitivity of 14 Hz.ppm−1 for toluene concentrations in the 130–1040 ppm range at room temperature, which is 4.5 times higher than the sensitivity obtained with films of similar thicknesses and porosities that were structured with F127.