Fingertip‐Skin‐Inspired Highly Sensitive and Multifunctional Sensor with Hierarchically Structured Conductive Graphite/Polydimethylsiloxane Foams

• Published in: Advanced functional materials 2019-05, Vol.29 (18), p.n/a
• Main Authors: Sun, Qi‐Jun, Zhao, Xin‐Hua, Zhou, Ye, Yeung, Chi‐Chung, Wu, Wei, Venkatesh, Shishir, Xu, Zong‐Xiang, Wylie, Jonathan J., Li, Wen‐Jung, Roy, Vellaisamy A. L.
• Format: Article
• Language: English
• Subjects: Bending machines; Detection; Functional materials; Graphite; healthcare monitoring; Human motion; Materials science; microstructure; multifunctional sensing; Polydimethylsiloxane; Porosity; Sensitivity; Sensors; Skin; skin sensor; temperature sensing; Texture recognition; Wrist
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201808829

Fingertip skin exhibits high sensitivity in a broad pressure range, and can detect diverse stimuli, including textures, temperature, humidity, etc. Despite adopting diverse microstructures and functional materials, achieving skin sensor devices possessing high pressure sensitivity over a wide linear range and with multifunctional sensing capabilities is still challenging. Herein, inspired by the microstructures of fingertip skin, a highly sensitive skin sensor is demonstrated with a linear response over a broad pressure range and multifunctional sensing capabilities. The porous sensing layer is designed with hierarchical microstructures on the surface. By optimizing the porosity and the graphite concentration, a fabricated skin sensor device exhibits a superior sensitivity of 245 kPa−1 over a broad linear pressure range from 5 Pa to 120 kPa. For practical application demonstrations, the sensor devices are utilized to monitor subtle wrist pulse and diverse human motions including finger bending, wrist bending, and feet movement. Furthermore, this novel sensor device demonstrates potential applications in recognizing textures and detecting environmental temperatures, thereby marking an important progress for constructing advanced electronic skin. Fingertip‐skin‐inspired skin sensors based on hierarchically structured conductive graphite/polydimethylsiloxane foams show high sensitivity in a wide pressure range. Furthermore, aside from sensing pressure, the skin sensors can distinguish the texture and temperature. Applications in monitoring physiological signals, distinguishing papers with different texture roughness, and indicating environmental temperatures are demonstrated.