Polyurethane rubber all-polymer artificial hair cell sensor

In this paper, we present the design, fabrication process, and preliminary testing results of an artificial hair cell (AHC) sensor made entirely of polymer materials from the substrate level up. The new AHC sensor utilizes polyurethane elastomers for sensing and structures. The AHC can detect two-axis deflection of a vertical polyurethane hair using carbon-impregnated polyurethane force sensitive resistors (FSRs). AHC with cylindrical hair cross-section exhibit sensitivity of 245 ppm resistance change for every micron (ppm/mum) of tip deflection. The AHC threshold detection level of 3 mum compares favorably with insect tactile hair cells having thresholds on the order of 30-50 mum. Furthermore, we have characterized the mechanical and chemical properties of two-part room-temperature-curing polyurethane elastomers in the context of microfabrication. Elastic properties, chemical resistance, thermal oxidative decomposition, and adhesion properties are tested and compared to the performance of polydimethylsiloxane (PDMS), a widely used elastomeric material. Polyurethane elastomer exhibit superior mechanical tear resistance and ability to adhere to substrates compared to PDMS