A novel PEG-based hydrogel possessing disulfide bonds: synthesis via click chemistry and study on swelling behavior

In this research, polyoxyethylene with alkyne end groups and two disulfide bonds in the polymer chain was synthesized through two consecutive esterification reactions from polyethylene glycol (PEG). A new PEG-based hydrogel with exceptional structural features was prepared from the polycycloaddition reaction of this macro-dialkyne with a triazidohydrin obtained from trimethylolpropane triglycidyl ether. The network structure of the hydrogel was investigated by FT-IR spectroscopy, elemental analysis, field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray (EDX) spectroscopy. The swelling behavior of the prepared hydrogel in water was studied by drawing the graph of water uptake percentage versus time. It was found that the hydrogel has the ability to absorb water more than five times its dry weight within 12 h. The water uptake rate of the prepared hydrogel was compared with several other hydrogels with similar structure. In addition to water, the swelling behavior was also checked in a number of organic solvents with different dipole moments. The prepared hydrogel showed significant solvent uptake (slightly more than twice the dry weight) in methanol and N,N-dimethylformamide solvents.