Melling, D.; Martinez, J. G.; Jager, E.

Ionic electro-active polymers (EAPs) are promising materials for production of fibre and textile linear actuators for active and haptic clothing. One approach to production is the electrodepositon of polypyrrole on a conducting fibre substrate. Synthesis conditions, geometric parameters and cycling conditions are known to impact the actuation of these films and require tuning to achieve optimum performance. Remarkably, we have observed that film thickness can be tuned to determine the type of actuation mechanism displayed. This behaviour is a consequence of changes in the structure of the polymer with film thickness. Changes in doping levels, effective conjugation coordinate, density, and porosity of the films with thickness, will be used to explain the observed behaviour. This behaviour has potential for exploitation for practical applications. It is vital that engineers are aware of these issues when designing EAP actuators with predictable and stable behaviour.