Development and characterization of an artificial hair cell based on polyurethane elastomer and force sensitive resistors

The performance of polyurethane (PU) and polydimethylsiloxane (PDMS) elastomers are compared in a battery of tests showing that the two PU formulations tested compare very favorably with PDMS mechanically and in terms of adhesion, while sacrificing some resistance to solvents and chemicals. PU is then used to form the structure and sensing elements of an all-polymer artificial hair cell. The demonstrated artificial hair cells are composed of a PU cilium on top of force sensitive resistors (FSRs) that detect cilium motion. The FSR is a mixture of carbon nanoparticles and PU, patterned using a newly developed method. Sensitivity of the demonstrated device (245 ppm/mum of tip deflection) is improved by an order of magnitude over previous single-axis polymer AHCs with additional improvements in robustness. Both carbon black and multi-walled nanotubes are tested as conductive fillers, with MWNT providing increased sensitivity