Flexible capacitive sensor based on 2D-titanium dioxide nanosheets/bacterial cellulose composite film

In this paper, titanium dioxide nanosheets (Ti_0.91O₂ NSs) were incorporated into bacterial cellulose (BC) film for dielectric property tuning while maintaining the flexibility of the resulting composite paper. By taking advantage of the improved dielectric constant, the nanosheets/BC composites were employed as capacitive sensors. The fabricated devices showed the highest sensing performance of ∼2.44 × 10^-3 kPa^-1 from 0 to 30 N when incorporating as little as 3 vol% of Ti_0.91O₂ NSs (or ∼2 wt% Ti). Stable operation and high robustness of the sensor were demonstrated, where simple human motions could be efficiently monitored. This study provided a route for preparing flexible and low-cost BC composite paper for capacitive sensor. The strategy for enhancing the dielectric properties as well as sensing performances of the BC demonstrated herein will be essential for the future development of biocompatible, low-cost, and eco-friendly wearable electronics.