Synthesis and characterization of artificial muscles based on SBS block copolymers with selective sulfonation of the phases

Abstract

Ionomeric Polymer-Metal Composites (IPMCs) are smart materials, which have a metal/polymer/metal sandwich-like structure and are capable to deform in response to electrical stimuli and vice versa. In addition, they have low density, flexibility, lightness, biocompatibility and low drive voltage. Therefore, they are promising materials for a wide range of applications, such as actuators, sensors, in robotics and as artificial muscles. The operating mechanism of these devices consists of the migration of hydrated ions within the polymer's ionomeric channels in response to an electric field generated after the application of a bias between metal electrodes. For this reason, its electromechanical performance depends on several factors mainly related to the polymeric membrane, such as ionic conductivity, hydration level and ionomeric channels morphology. However, these materials present a series of problems that need to be solved to enable industrial production and applications. Among them, it is highlighted high cost, high temperature ion conductivity lost, low flexibility and random morphology. On the other hand, the styrene-butadiene block copolymer (SBS), is an important thermoplastic elastomer that can be synthesized in order to produce a nanostructured morphological structure, with well-defined domains, which can be selectively sulfonated to develop an ionomer specifically designed for favourable ion migration, maintaining mechanical properties of high flexibility and resistance. For this reason, this project aims at the development and electromechanical characterization of artificial muscles based on SBS with nanostructured morphology and selective sulfonation of the phases, aiming to develop a technological device, with high ion migration capacity, high electromechanical performance, low cost and with industrial application. (AU)