One-pot preparation of ultrastrong double network hydrogels

A double-network (DN) polyethylene glycol/polyacrylic acid (PEG/PAA) hydrogel with high compressive strength was synthesized by one-pot solution polymerization. The PEG network crosslinked by glutaraldehyde (GA) was fabricated via condensation reaction while the PAA network crosslinked by N,N'-dimethylenebiacrylamide (MBAM) via free-radical polymerization. The components of hydrogel were analyzed with Fourier transform infrared spectroscopy (FTIR). Mechanical strength of PEG/PAA hydrogels was examined, and the results showed that the addition of GA and PEG endowed the DN hydrogel with a high compressive strength of 10.9 MPa in a water content of 90 wt% due to lightly crosslinking and special entangled bundles morphology. Morphological studies showed that the hydrogels exhibited various pore structures when they were synthesized using different molar ratio of GA to PEG. This work provided a simple way to prepare ultrastrong DN hydrogels.