Fabrication of kapok fibers and natural rubber composites for pressure sensor applications

Biomass-based composites are of immerse importance because they allow combining properties in ways that are not found in nature. This work reports facile routs to produce pressure sensor in large scale from biomass kapok fibers and natural rubber. Two different strategies were applied to introduce conductive elements into the pressure sensor and are systemically compared, which include carbonization of the tubular kapok fibers and coating the fibre with conductive polymer. When used as a pressure sensor, the kapok fiber and natural rubber-based composites can respond logarithmically to the loading in the compressive strain range of 0 ~ 15% with excellent recyclability. As a prototype of the concept for practical application, a weight scale was constructed using the kapok fiber and natural rubber-based composites and showed distinct weight-dependent resistance changes, being feasible for measuring weight within a certain weight range. Besides, the strategy based on conductive polymer enables the pressure sensor to be insulative at its original state and become conductive when pressed, hereby making the composite a potential pressure-sensing material and pressure-responsive circuit switch. This study provides a platform for developing biomass-based electronic pressure sensors.