Soft Multifunctional Porous Sponge Sensor for Pressure and Strain Using Liquid Metal/Polydimethylsiloxane with Silver-Nanowire-Coated Composite

Abstract

Compression and tension sensors with a porous structure have attracted attention recently. Porous sponge sensors have the advantage of a wide deformation range owing to their structural characteristics. In this study, a porous sponge structure was prepared by absorbing polydimethylsiloxane (PDMS) into the matrix of porous commercial sugar cubes. A conductive network was formed by coating the outside of the sponge skeleton with silver nanowires (AgNWs), which have a high aspect ratio. In addition, a liquid metal (LM), which does not directly form an electrical network but changes from zero-dimensional to one-dimensional under an external force was introduced into this porous sponge structure. The effects of the LM on the sensor sensitivity to pressure and strain were analyzed by comparing the electrical resistance changes of PDMS/AgNW and LM/PDMS/AgNW sponge sensors under tension and pressure. This study shows that the use of a porous structure and an LM may be useful for future wearable sensor design.

Recent progress of flexible pressure sensors: from principle, structure to application characteristics

“…In recent years, people have put forward more requirements for the performance of flexible pressure sensors, so much research has been conducted to improve and optimize the structure and materials of the sensors. On the one hand, many studies have produced and expanded functional materials including carbon nanotubes (CNTs) [30,31], silver nanowires (AgNWs) [32][33][34], graphene [35,36], and so on. On the other hand, by micro-designing the sensor structure, such as pyramids [37][38][39], multi-microholes [40,41], micro-columns [42,43], and so on, the pressure response performance of the sensor can be improved.…”