Physical Chemistry

Optical tactile sensor using scattering inside sol–gel-derived flexible macroporous monoliths


  • Gen Hayase National Institute for Materials Science


Tactile sensors are an essential technology for robots, and various types have been developed. This paper reports on a new optical tactile sensor based on multiple scattering in a porous material with a viscoelastic phase-separated structure fabricated by a sol-gel method. When a macroporous silicone monolith with a few micrometer diameter skeletons was compressed, the diffuse light intensity near the light source was reduced due to Mie multiple scattering. A simple tactile sensor using a macroporous monolith and a photo reflector was fabricated based on this finding. The skeleton diameter was an important factor for the sensor. In the case of macroporous silicones, the voltage-strain curve showed an almost hysteresis-free clear response. However, the response of macroporous polymethylmethacrylate monolith with a smaller skeleton diameter was weak due to low Mie scattering intensity. Using cell structure materials with a scale much larger than the optical wavelength, a decrease in light intensity with compression was not observed. Sensors using sol-gel-derived flexible macroporous monoliths could provide features such as thinness and improved surface tactility.


Thumbnail image of ms.pdf

Supplementary material

Thumbnail image of SI.pdf
Supporting Information
Movie list, schematic of the optical tactile sensor using Arduino Nano, and the sample code.