Cellulose Nanofibers/PEDOT:PSS Conductive Aerogel for Pressure Sensing Prepared by a Facile Freeze-Drying Method

The application of flexible wearable pressure sensors in the fields of pressure sensing, electronic skin, and human health monitoring has attracted a lot of attention. Herein, cellulose-nanofiber (CNF)-based aerogels with conducting polymer poly(3,4-ethylene dioxythiophene)/poly(styrenesulfonate) (PEDOT:PSS) and glutaraldehyde (GA) as cross-linking agent were designed and prepared by sol-gel cross-linking and freeze-drying. Without any special treatment, these aerogels presented good flexibility and piezoresistive properties. As the analysis of SEM, Raman spectrum, and XPS, the introduction of GA not only improves the mechanical properties of aerogel (the compressive strength at 80% strain has increased from 48 to 66 kPa) but also affects the doping state of PEDOT, which improves the sensitivity of aerogel (from 10.65 to 15.18 kPa^-1). In addition, the sensor has been successfully applied to monitor human movements, including not only large movements (joint movements) but also small-scale muscle movements (cheek puffing and articulation recognition). It shows its potential as a widely used green pressure sensor.