Conducting polymers bending artificial muscles

The intercalation of dopants to conducting polymer chains leads to an increase in volume of up to 30 % [8], This property is used in actuators (polymer-based artificial muscles). Bilayer structure of polypyrrole-based anode and cathode is a simple model. At anode, p-doping of polymer occurs to swell, while the other side shrinks because of the expulsion of counterions. This volume changes promote a bend of the layers. The change of poles cancels the volume changes and gives rise to the movement in the opposite direction. 

Secondly, conjugated polymers were studied as biomimetic artificial muscles. A scalable physics based electro-chemo-mechanical model was developed to connect an input voltage to bending of the material. The reduced version of the model was used to design a robust adaptive controller. Also, a nonlinear mechanical model was investigated. Furthermore, a torsional actuator was developed by depositing PPy on a tube substrate with helically wound platinum fibers. A set of experiments were conducted to confirm the torsional and other actuation modes as well as the model. 

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