A synthetic chemical strategy aimed at altering the cross-linking density of the electropolymerized conjugated polymer
polypyrrole has been devised and implemented. The actuation performance of the synthesized material was assessed
using a new type of apparatus capable of making rapid, non-contact dynamic measurements. The affect of cross-linking
on the actuation performance of polypyrroles, was investigated.
A comparative study has been made to explore the potential benefits of newly available single-crystal ferroelectric materials
when used in a practical device, in this case an ultrasonic micro-motor. This type of micro-motor exhibits exceptional power-to-weight characteristics, which could be exploited beneficially, for example, in unmanned air-vehicle (UAV) systems. The
operating principles of a range of commercial and experimental motor designs were evaluated objectively in order to identify
areas of performance that can potentially be enhanced using PMN-PT single-crystal piezoelectric ceramics. Based on this
analysis a practical motor design was selected for construction and experimentation. Detailed numerical analysis indicated
that a motor constructed from single crystal PMN-PT could be expected to provide an improvement in motor stall-torque by
up to a factor of 2.8 and a no-load speed improvement by a factor of 1.5 when compared with motors based on standard
polycrystalline lead-zirconate-titanate (PZT) ceramics. In practice single-crystal versions of the motor were found to produce
double the power output of their polycrystalline counterparts. Overall efficiency was found to be improved two-fold. There
were significant discrepancies between the numerical predictions for the single-crystal devices and their measured
performance, whereas the polycrystalline devices were found to perform closely in line with predictions.