Chemical Engineering

Hydrogels, distinct from solid materials are composed of a hydrophilic polymer network and large amount of water. Hydrogels can undergo signifi cant changes in their physicochemical properties with variation of temperature, pH, light, biomolecules, salts, electric fi eld, pressure, and so on. Th is special soft wet structure of hydrogels has enabled them to be used as biocompatible materials for a variety of applications, such as biosensors, bioseparation, drug release vehicles and tissue engineering scaff olds and hence being paid a lot of attention for several decades by researchers from material science, biomedical science and polymer science. We present a novel approach to the fabrication of advanced polymeric nanocomposite hydrogels from polyacrylamide (PAAm) by incorporation of graphene-silver-polyethylenedioxythiophene-polystyrene sulfonate (rGO-Ag-PEDOT/PSS) by photopolymerization method. Infrared spectroscopy was employed to characterize the structure of the hydrogels. Th e internal network structure of nanocomposite hydrogels was investigated by scanning electron microscope. Swelling, deswelling and mechanical properties of the hydrogels were investigated.

 

           

 

The compressive strength of nanocomposite hydrogels reaches maximum of 1.71 MPa when the ratio of rGO-Ag-PEDOT/PSS to PAAm was 0.3 wt%, which is 1.57 times higher than that of PAAm hydrogels (1.09 MPa). For the fi rst time, PAAm and its series of nanocomposite hydrogels have been successfully synthesized by in situ photopolymerization method. Graphene oxide was fully exfoliated into individual sheets. Th e tensile strength of PAAm hydrogel improved with the addition of rGO-Ag-PEDOT/PSS nanocomposite. Th e electrical conductivity of the PAAm-rGO-Ag-PEDOT/PSS nanocomposite hydrogel was found to be 3.91×10-5 S cm-1. With the improved mechanical, thermal and electrical properties, may broaden the applicability of the nanocomposite hydrogels in various fi elds including drug release, bio-sensors, actuators, enzyme immobilization and molecular separation.