Facile Preparation of Polymer-Grafted Halloysite Nanotubes via a Redox System: a Novel Approach to Construct Antibacterial Hydrogel

We demonstrate the use of a supernormal valence transition-metal (Ce(IV) and Cu(III))-mediated redox system for the surface grafting on the halloysite nanotubes (HNTs). Following this way, commonly-used vinyl monomers were grafted on HNTs in one step under mild condition. The grafting was evidenced using FTIR, X-ray photoelectron spectroscopy (XPS), and thermogravimetric analysis (TGA). The micro-morphology was carefully characterized by transmission electron microscope (TEM). The results indicate that the surface grafting reaction was successfully processed in all cases, in which the Ce(IV) shows a much higher initiation activity than that of Cu(III). Then a uniform hydrogel was constructed by mixing poly(triethyl(4-vinylbenzyl)phosphonium chloride-grafted HNTs (HNTs-P(Et-P)) with sodium polyacrylate-grafted HNTs (HNTs-P(AA-Na)), which show desirable antibacterial activity.