ABSTRACTThis paper reports the development of micromachining processes, as well as electrical and mechanical evaluation of a stimuli-responsive, mechanically-dynamic polymer nanocomposite for biomedical microsystems. The nanocomposite, which consists of a cellulose nanofiber network embedded in a poly(vinyl acetate) matrix, was shown to display a switchable stiffness comparable to bulk samples, with a Young’s modulus of 3570 MPa in the dry state, which reduced to ~25 MPa in the wet state, with a stiff-to-flexible transition-time dependent on exposed surface area. Upon immersion in phosphate buffered saline, the ac resistance through the PVAc-TW thickness was found to reduce from 8.04 MΩ to ~17 kΩ. Electrochemical impedance of an Au electrode on PVAc-TW was found to be ~178 kΩ at 1 kHz, and this was found to be stable as the probe shank was flexed to compress the metal, but increased with increasing flex angle when the metal was flexed into a tensile state.
Analytical modelling of thermal residual stresses and optimal design of ZrO2-(ZrO2+Ni) sandwich ceramics