3D porous sponge-like sensors prepared from various conductive nanohybrids-filled melamine sponge toward human motion detections

Melamine sponge (MS) is a commercial material with low density, high porosity, and superior elasticity, which has been utilized to design and produce three-dimensional (3D) porous sponge-like sensors. Notably, this material is environment-friendly and inexpensive. In the present study, an MS filled with various hybrid source bridges, as 3D porous sponges, was designed and prepared by using a simple and low-cost immerse-filling method and then submerged into various hybrid source mixtures with the support of an MS framework with a hole-opened structure. The structurally morphological, chemical, thermal, and mechanical properties of the as-obtained 3D porous sponges were further determined for potential changes in the structure of these sponges after filling the hybrid source mixtures in/on the MS framework. The presence of functional hybrid sources in the 3D porous sponges indicated that such sponges have reached a good sensitivity, stretch ability, and repeatability under compressing, stretching, bending, and twisting deformations. In addition, these sponges were effectively applied for detecting and monitoring concomitantly small- and large-scale movements of the human body, that is, the various motions of the knee, elbow, finger, wrist, and foot insole. Therefore, the 3D porous sponges prepared in this study can be considered as a promising candidate for practical applications as flexible or wearable devices.