Synthesis of a directionally-conductive polyaniline hydrogel composite by vapor deposition.

Abstract

Electroactive polymers (EAPs), including conducting polymers (CPs) such as polyaniline (PAn), and hydrogels are exciting areas of research in disciplines such as biomedical engineering, with the goal of creating low-cost, lightweight, non-toxic artificial muscles with characteristics similar to natural muscle. Such a material could be used to create more natural prosthetic limbs or artificial heart muscle, which could be implanted in the left ventricle to assist patients with congestive heart failure. Currently, however, electroactive polymers are not a viable replacement for natural muscles for a variety of reasons, including insufficient applied force and lack of robustness [1]. Hydrogels suffer from many of the same limitations [2]. Electroactive polymers include conducting polymers (CPs) such as polyaniline (PAn), which has the general structure [(-B-NH-B-NH) y (-B-N=Q=N) 1-y ] x , where B is a C 6 H 4 ring in the benzene-like arrangement and Q is the same ring in the quinone-like arrangement. The 50% oxidized form, which is the most conductive, is termed emeraldine (y=0.5). Polyaniline is currently used in anti-corrosive coating and staticdissipating compounds, and has been proposed for use in electrochromic windows, flexible circuit boards, and conductive fabrics. Many research groups have developed methods for creating novel polyaniline structures and composites. However, the processibility of polyaniline is currently poor, and further work needs to be done before polyaniline or its composites can be considered viable artificial muscles [3]. This thesis describes a novel and exciting method for the creation of a patterned polyaniline-hydrogel composite which shows directional conductivity, a material which vi has not been reported in the literature as far as we are aware. This material could provide the foundation for a micro-or nano-patterned composite which would further the goals of developing a viable artificial muscle with a directed pattern of contraction. vii

A facile and low-cost route for producing a flexible hydrogel–PANI electrolyte/counter electrode applicable in dye-sensitized solar cells (DSSC)

“…5b, the relationship between the increase in the percentage of PANI and higher T g values can be observed: Gel:PANI 2, Gel:PANI 4 and Gel:PANI 6 presented glass transition temperatures of 9, 12 and 16 °C, respectively. This finding confirms that the interactions between the hydrogel and the conductive polymer reduce the overall mobility of the hydrogel chains and function like physical cross-links [13].…”