Design and fabrication of highly-durable stretchable electronic platform with decoupling capability of tactile stimuli

Abstract

The need for electronics with new forms is emerging in various fields including healthcare, robotics, medical devices, and human-machine interfaces. Compared to conventional rigid material-based electronics, stretchable electronics can improve user convenience through various shapes and functions. Recently, stretchable electronic skin inspired by human skin is easy to change shape and can collect various physical senses. To this end, various polymer-based tactile sensors and electronic skin were presented, but there was a problem that durability and accurate tactile detection were difficult. Therefore, this study aims to accurately detect various tactile senses and secure high durability for various variations. First, in order to properly imitate the human skin sensory ability, accurate strain detection of tactile sensors is very important. Therefore, a pressure insensitive strain sensor is presented. Microcracks occur in the multi-wall carbon nanotube (MWCNT) network when the strain is applied, causing a large change in resistance at the 70% strain to have a gauge factor of 56. Second, accurate pressure detection that is not affected by the lateral strain and temperature is very important. An ultra-high sensitivity of capacitive pressure sensor based on the porous pyramid dielectric layer was developed. The improved sensitivity is because the compression coefficient is lowered and the effective dielectric constant changes significantly under pressure. Third, integrating robust components into the soft polymer matrix is considered the most feasible architecture that enables stretchable electronic devices. Here, we designed a Ferris wheel-shaped island (FWI) that can effectively suppress crack propagation at an interface in various deformation modes. Stretchable electronic products composed of various rigid components (LEDs, coin cells) were demonstrated using essentially stretchable printed electrodes. In addition, it has been proven that the electronic skin can distinguish various tactile stimuli without interference.