Swelling and thermal properties of porous PNIPAM/PEG hydrogels prepared by radiation polymerization

In this study,a series of porous intelligent hydrogels were synthesized by radiation exhibiting the lower critical solution temperature（LCST） and fast response involving a combination of A’-isopropyl acrylamideas monomer, polyethylene glycol（PEG） as pore-forming agent and N,N-methylene-bis-acrylamide as crosslinking agent.The hydrogels were analyzed by Fourier transform infrared spectroscopy,and the influence of radiation doses on their swelling and thermal behaviors were studied.Their surface morphologies were examined by scanning electron microscopy.The results showed that PEG molecules only acted as pore-forming agent in the cross-linked polymerization.Their swelling ratios reduced with increasing radiation doses.The LCST was around 37℃,and varied little with the radiation doses.The frozen water content of PNIPAM/PEG6000 hydrogel reduced with increasing the radiation dose,and was greater than that of PN1PAM hydrogel at 15 kGy.Hydrogel macropores were prepared by PEG agent,and the hydrogels without PEG had a dense surface.The porous hydrogels are expected to be applied in the field of artificial intelligence material.