Preparation of molecular imprinted thermosensitive gels grafted onto polypropylene by plasma-initiated graft polymerization

A novel molecular imprinted thermosensitive microgel grafted onto a supporting substrate by plasma-initiated graft polymerization was developed to adsorb and/or desorb a specific heavy metal by employing temperature swing. The grafting condition for the thermosensitive N-isopropylacrylamide (NIPA) gel, cross-linked with N,N′-methylenebisacrylamide, onto the surface of a nonwoven polypropylene (PP) film was investigated. It was found that the NIPA gel could be successfully grafted by the graft polymerization in a mixture solution of water and ethanol. The cross-linked NIPA gel, copolymerized with N-4-(vinylbenzyl)ethylenediamine (VBEDA) of a chelating group, was grafted onto the PP film by graft polymerization in an aqueous 50 wt% ethanol solution. During the polymerization, VBEDA and Cu(II) ions as a template undergo complexation and then multi-point adsorption sites are formed by removing these Cu(II) ions. The grafted imprinted-NIPA–VBEDA gel adsorbed and desorbed Cu(II) ions by virtue of the temperature swing, which occur due to the reconstruction/destruction of the multi-point adsorption sites corresponding to the shrinking/swelling of the gel network.