Control of the Energy Conversion in Radial Microactuators Using Conductive Polymers

Conductive polymers (CPs) represent new controllable and low cost materials for microactuation. During the electrochemical doping process, polymer changes its volume, when a voltage is applied. Different combinations have been studied and among them the combinations with the new CPs, like P(VDF-TrFE-CFE) Terploymer (PVTC) placed between polyaniline (PANI) electrodes, present higher conductivity, when there are used for radial microactuation. The cycle life of $10^{6}$ order justifies tuning the actuator performances. The operating structures were reproduced at molecular level with HFSS program (by Ansys). The tensile stress was of ca. $0.8-2.6 \mathrm{MPa}$, at operating voltages $\pm(1 \ldots 4) \mathrm{V}$. An energy conversion efficiency of about 30-50 % was obtained, but with peaks even higher, for a radial strain of up to 80%, depending on the actuator dimensions and doping level. Dopants like metals from nitrates or chlorides $\left(\mathrm{Au}^{+}, \mathrm{Cu}^{2+}\right.$ cations) or soaking acids $\left(\mathrm{HNO}_{3}\right)$ in PEDOT:PSS or BaZr
0.2
Ti
0.8
O
3
in Terpolymer have been considered for increasing the electrical conductivity in the polymer matrix. The radial, respectively tangential strain of the $C P$ radial actuator has been determined and the simulation data have been used to calculate the energy conversion efficiency of the CP actuator. The method generates characteristic parameters of the optimal structure to be synthesized, for the highest energy conversion rate, considering also new dopants and CPs in combination.