Patterning of Highly Conductive Conjugated Polymers for Actuator Fabrication

Trilayer polypyrrole microactuators that can operate in air have previously been developed. They consist of two outer layers of the electroactive polymer polypyrrole (PPy) and one inner layer of a porous poly(vinylidene flouride) (PVDF) membrane containing a liquid electrolyte. The two outer layers of PPy are each connected with gold electrodes and separated by the porous PVDF membrane. This microtool is fabricated by bottom-up microfabrication. However, porous PVDF layer is not compatible with bottom up microfabrication and highly swollen SPE suffers from gold electrode delamination. Hence, in this MSc project/thesis a novel method of flexible electrode fabrication with conducting polymers was developed by soft lithography and drop-on-demand printing. The gold electrodes were replaced by patterned vapor phase polymerized (VPP) poly(3,4-ethylenedioxythiophene) (PEDOT) electrodes due to its high electrical conductivity and versatile process ability. The replacement of the stiff gold electrodes by flexible and stretchable PEDOT allowed high volume change of the material and motions. The PEDOT electrodes were fabricated by patterning the oxidant iron tosylate using microcontact printing and dropon-demand printing. Moreover, the PVDF membrane has been replaced by a nitrile butadiene rubber/poly(ethylene oxide) semi-interpenetrating polymer network (IPN) to increase ion conductivity and strechability and hence actuator performance.