Novo hidrogel eletro, pH e termoresponsivo para aplicações em músculos artificiais e atuadores

Abstract

Artificial muscles and actuators are part of one of the most researched fields in the polymer area in the present time. They have potential applications in areas such as drug delivery,sensors, selective membranes, robotics and tissue engineering. This work has the objective to synthetize and to test the hydrogel composed of the copolymer poli(N-isopropyl acrylamideco-acrylic acid) and polyaniline conducting polymer for applications in this area. The hydrogel copolymer was synthetezed while polyaniline was polymerized later, inside ofstructure of hidrogel through the oxidation of aniline in ammonium persulfate in acid solution. The hydrogel showed complete and homogeneous structures with high mechanical strength capable of withstanding some processes of expansion and contraction. Moreover, the hydrogels showed a conductivity in the order of 10-1S/cm for concentrations of 20% and 23,1% of polyaniline and 2S/cm for 35%. In the dynamic tests employed for evaluation of contraction and expansion, the materials demonstrated a fast response, inversion of movement, easily reproductable stability of force levels and movements. Having a triple responsive characteristic, this material presented sensitivity to temperature, pH and electric current with inverse and direct polarity providing characteristical movements for each one. In these tests, some parameters had been studied as such the amount of polyaniline, mass of the sample, tension and electric current and concentration of the electrolytic solutions with intention to describe the performance of the artificial muscle under some conditions and to determine the forces, the velocity and the type of response of this muscle for some applications. In all these tests the materials presented resulted satisfactory results becoming an attractive option to be used in formulations related to artificial muscles and actuators