Development of a Flexible Conductive Polymer Membrane on Electroactive Hydrogel Microfibers

Abstract

Conducting polymers and hydrogels are two classes of polymers that currently receive an increasing attention in the field of biomaterials, particularly for their application in the assembly of artificial muscles. In this paper we present the development of Polyacrylamide (PAAM) microfibers and polyaniline (PANI) -poly vinyl alcohol (PVA) conductive gel membrane. The fabricated PAAM microfibers have diameters between 1 and 12µm depending on the preparation parameters. These microfibers respond instantaneously to 100mV electrical stimulation, which solves the problem of time response of the hydrogels. On the other hand, we showed that the inclusion of conducting chains within a crosslinked gel matrix allows combining the conductivity of the PANI with the mechanical flexibility of PVA in order to provide flexible gel membranes that can adhere to the PAAM microfibers to ensure their electrical stimulation.

Electrospinning of highly aligned and covalently cross‐linked hydrogel microfibers

“…The second challenge faced was the generation of highly aligned fibers. Thus, a new electrospinning setup was implemented to obtain well oriented fibers that are ready to be used in complex devices …”

“…Cross‐linked polyacrylamide (PAAM) hydrogel is a biocompatible actuating and sensing polyelectrolyte that adapt and respond to physicochemical, electrical, and biochemical stimulations . It is the most suitable material to be used in mimicking the biological muscle.…”

“…Therefore, the fabrication of well‐aligned and highly ordered hydrogel microfibers is strongly needed to use them into a complex muscle architecture . The fibers micrometer scale improves mechanical properties and the time of response of the device .…”

“…The fibers micrometer scale improves mechanical properties and the time of response of the device . If these conditions are met, the fabrication of an artificial muscle with strength and speed matching and even greater than that of a human muscle may be possible by assembling a large number of small elements acting in parallel …”

Artificial muscular microfibers: hydrogel with high speed tunable electroactivity

“…The new electrospinning setup originality lies in the combination between the shape of the collector, its position relative to the polymer jet and the use of hot air flow. 26 The collector design is based on the concept of having two square conducting frames placed in parallel and electrically connected together in a way to stretch the polymer while the nozzle head location is determined in a way to allow the main jet to split into several sub-jets of thinner diameters. The hot air flow controls the evaporation rate of water contents in the fibers.…”