ARTIFICIAL MUSCLES FROM BILAYER STRUCTURES

A different electrochemical behaviour of polypyrrole in different solvents is observed. Differences are attributed to the presence of interactions between solvent and polymer. These interactions change when die polymer is oxidized or reduced. The high polarity of water promotes an intense interaction with polarons and bipolarons. During oxidation counterions and water molecules penetrate in the polymer promoting an important swelling and molecular strain. Counterions and water molecules are expelled from the polymer during reduction promoting its contraction. The effect is lighter when different solvents are used. A bilayer structure polypyrrole-flexible and inactive polymer was constructed to transform molecular strain in macroscopic movements. An artificial muscle (electrochemomechanical device) was constructed. Electrical currents trigger oxidation or reduction (chemical) processes developing a mechanical movement. The movement can be stopped or inverted by stopping or inverting the current flow.