| Abstract
| - Surface functionalization of low-density polyethylene (LDPE), silanized glass, and free-standingpolyaniline (PANI) films via UV-induced graft copolymerization with 1,1‘-bis(4-vinyl-benzyl)-4,4‘-bipyridinium dichloride (VBV) was carried out. The vinyl group containing viologen was synthesized bythe double Anderson reaction using 4,4‘-bipyridine and vinyl benzyl chloride and characterized by elementalanalysis, FTIR spectrum, and X-ray photoelectron spectroscopy. The graft copolymerization of VBV wascarried out by placing the plasma-pretreated substrate in contact with an aqueous solution of VBV underUV irradiation. The effects of the plasma-pretreatment time of the substrate, UV-induced graftcopolymerization time, and monomer concentration on the VBV-graft copolymer concentration wereinvestigated. The responses of the VBV-graft-copolymerized LDPE films and silanized glass slides tophotoirradiation were monitored. In both cases, intensely blue viologen radical cations were formed after10 min of UV irradiation in a vacuum and bleaching occurred when the substrate was exposed to air upontermination of the irradiation. VBV-graft-copolymerized PANI films with good conductivity can be prepared,and these films may have possible applications as active templates in biosensors where the viologen groupsmay serve as electron transfer mediators from the electrode surface to the active site of biomaterials. Thismethod of surface functionalization of viologen moieties offers a number of advantages over a previouslydeveloped technique.
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