Dynamic chemical vapor sensing with nanofibrous film based surface acoustic wave sensors

We report on the use of electrospun nanofibrous film for surface acoustic wave (SAW) sensors to enhance its chemical detection capability. Ultrafine (100–300 nm) polyethylene oxide (PEO) fibers with controlled thickness and porosity were electrospun-coated on the surface of a ST-cut quartz SAW sensor. The nanofibrous film provides a high surface area to volume ratio, which can not only offer more adsorption sites for vapor molecules, but also shortens the diffusion length of vapor molecules into polymer material. Compared to conventional thin film coating techniques, the nanofiber-coated SAW sensor shows a higher sensitivity and faster response (shorter adsorption/desorption times). In addition, a theoretical analysis was performed to understand SAW sensor response with nanofibrous film coating. It is concluded that the nanofiber film holds a great potential in enhancing SAW sensor performance for trace level detection of chemical analytes.