Impact of hydrophilic bamboo cellulose functionalization on electrospun polyacrylonitrile nanofiber-based humidity sensors

Quartz crystal microbalance-based humidity sensors with sensing layer of bamboo cellulose (BC)-overlaid polyacrylonitrile (PAN) nanofibers were fabricated using electrospinning and drop-casting processes. Scanning electron microscopy, water contact angle measurement, and Fourier-transform infrared spectroscopy were employed to investigate the morphology, wettability, and chemical composition of the nanofibers, respectively. Impact of varying BC concentration on the sensing response toward relative humidity (RH) was evaluated, where higher BC concentration resulted in more responsive sensor behavior (higher-frequency shift) toward RH. This work highlights a simple method to enhance the humidity-sensing ability of electrospun nanofibers by overlaying them with hydrophilic materials.