Capacidad sensora de las reacciones electroquímicas del Polipirrolhacia el origen de la propiocepción natural y artificial

Abstract

Human and animal natural muscles feel the mechanical, thermal or chemical working conditions during actuation: they are haptic muscles. Some researchers suspect that the chemical reaction itself that drives the actuation is the origin of the sensing signals sent back to brain. In order to verify this issue, in this thesis polypyrrole films are used as model material of the intracellular matrix in the sarcomere (molecular machines, ions and water). At the oxidation and the reduction, they exchange ions and water with the electrolyte solution, becoming a dense and reactive gel where every polymeric chain is an electrochemical molecular machine. By the use of different electrochemical techniques (cyclic voltammetry, square potential waves and square current waves), the response of these reactions to changes in temperature, electrolyte concentration or frequency of imput signal are studied. Both, the charge and energy consumed and the evolution of the potential change with the working conditions during the reaction. Starting from the reaction rate equation, new sensing equations are obtained: they quantify the relationship between every sensing magnitude with every experimental variable. Experimental results fit the sensing equations developed. It corroborates the new sensing principle: reacting systems (constituted by chemical or electrochemical molecular machines) submitted to energetic perturbations respond to them by varying the reaction energy, or any of its components, to the new imposed energetic conditions. Both the experimental results and the theoretical development identify the chemical and the electrochemical potential during the reaction (that define the energetic conditions of the reaction) are the origin of the sensing signals in artificial muscles and, probably, of the signals detected by the neurotransmitters in natural muscles and sent back to the brain containing information about thermal, chemical, electric or mechanical working conditions. http://repositorio.bib.upct.es/dspace/