A microwave driven smart hydrogel: Poly(n-isopropylacrylamide) based network semi-interpenetrated with polyaniline

MOLINA M.A.; RIVAROLA C.R.; BARBERO C.A.

Simposio; V Argentine-Chilean Polymer Symposium ARCHIPOL 09; 2009

Crosslinked acrylamide based hydrogels are interesting candidates for technological applications, such as drug release.1 Specifically, hydrogels sensitive to external parameters (pH, temperature, ionic force, electric field, etc) constitute the so called “smart” hydrogels which could react actively to changes in the environment.2 The materials could also be used in chemical or mechanical actuators since they change volume and expel a significant amount of its inner solution when a transition is induced by external action. Most of the external actions involve slow changes in the complete environment of the gel. It would be most interesting to induce the volume change at a distance using electromagnetic radiation. Indeed, smart hydrogels driven by NIR radiation absorption has been proposed.3 It is known that conductive polymers absorb strongly electromagnetic radiation, specifically in the microwave range, with heating up of the polymer.4 By compositing a smart hydrogel matrix with a conductive polymer it would be possible to induce the hydrogel temperature transition using microwave radiation. In the present communication the use of polyaniline (PANI), semi-interpenetrated (sIPN) inside thermosensitive poly(N-isopropylacrylamide) based hydrogels, to induce a temperature transition by microwave absorption is demonstrated.