Mesoporous Coated Films on Love Wave Acoustic Devices for Gas Detection

This work presents a guided Love wave sensor for gas detection, based on a mesoporous oxide sensitive film, showing remarkable sensitivity to ethanol exposure, higher than 10 Hz/ppm, and a response time shorter than one minute. This paper details the complete process used for designing this platform from the newly developed deposition techniques for the mesoporous sensitive film to the acoustic sensor conception. Indeed in order not to damage the transducers, the deposit should be accurately located on the acoustic path of the sensors. Specific deposition techniques based on Kapton^® masking, SU8 sacrificial layer masking and a capillarity bench have been developed. Homogeneous clean-edged silica and titania mesoporous layers could be achieved. Sensing operation was demonstrated under ethanol exposure (130–2000 ppm), with high sensitivity, reversibility and reproducibility.