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.

Version notes

Addition of references in the manuscript and modifications of a movie list, figures, and a sample code in the SI.


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Supplementary material

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Supporting Information
Movie list, schematic and photos of the optical tactile sensor, and the sample code.