Hybrid film-like strain sensors prepared from polydimethylsiloxane-covered 3D porous network sponges toward human motion detection

Flexible and wearable sensors have attracted increasing attention for use in human motion detection. In this study, various porous network sponges covered in polydimethylsiloxane (PDMS) as hybrid films with and without silver nanomaterials were fabricated for use as strain sensors using a simultaneous immersion-covering method. The structural, morphological, chemical, thermal, and mechanical properties of the as-obtained hybrid film-like strain sensors were investigated to clarify the possible interactions in the entire structure of the PDMS-covered porous network sponges. These investigations indicate that the framework structure of the porous network sponges in the PDMS matrix plays a critical role in the sensing performance and mechanisms of these strain sensors. Owing to the obtained structural integrity and the existence of functional hybrid sources, the hybrid sensors demonstrated good sensitivity, stretchability, and stability under repeated stretching, bending, and twisting deformations. Finally, the as-obtained hybrid film-like strain sensors were effectively used to simultaneously monitor small and large deformations of the human body, that is, the bending movements of the knee, elbow, finger, and wrist. Therefore, hybrid films with tailored structures can be developed for various practical applications, serving as promising strain sensors for use in flexible and wearable devices.