Thiophene-based conducting polymer molecular actuators

Traditional conducting polymer actuators such as polypyrrole offer tremendous active stress at low actuation voltages but with moderate strain, strain-rate and efficiency. We report the synthesis of novel thiophene based conducting polymer molecular actuators, exhibiting electrically triggered molecular conformational transitions. In this new class of materials, actuation is the result of conformational rearrangement of the polymer backbone at the molecular level and is not simply due to ion intercalation in the bulk polymer chain upon electrochemical activation. Molecular actuation mechanisms results from (pi) $min(pi) stacking of thiophene oligomers upon oxidation, producing a reversible molecular displacement which is expected to lead to surprising material properties such as electrically controllable porosity and large strains. The hypothesis of active molecular conformational changes is supported by in situ electrochemical data. Single molecule techniques are considered for molecular actuator characterization. Mechanical properties of these new materials are currently being assessed.