The cooperative actuation of multistep electrochemical molecular machines senses the working temperature: voltammetric study

Electrochemical reactions of conducting polymers drive conformational movements of the constitutive polymeric chains (molecular motors or molecular machines), generating or destroying the required free volume to exchange balancing counterions and solvent. The influence of the temperature on the reversible oxidation/reduction of a polypyrrole film in NaCl aqueous solutions was studied here by cyclic voltammetry. Under constant potential limits, constant scan rate and constant electrolyte concentration the extension of the reversible reaction, defined by the coulovoltammetric charge, increases for rising experimental temperatures. That means that the reaction charge is a function of, and senses, the working temperature. Based on the empirical chemical kinetics of the reactions a theoretical description was attained resulting in a sensing equation. The attained results could explain how muscles from cold-blooded animals work and are aware of the thermal working conditions.