Applications Of Conductive Polymers In Molecular Imprinting And Antioxidant

In the past twenty years conductive polymers have been the subject of intense research activity because of their high conductivity and unique redox chemistry. There have been many reports on the preparation, characterization and applications of various forms of conductive polymers. At the present time, the potential role of polyaniline and related conducting polymers in biomedical and analytical chemical application has attracted considerable interest. The free radicals such as OH·and ROO·in organisms are oxidative, thus their antioxidant ability is important for their biomedical applications. On the other hand, molecular imprinting technique (MIT) has also received growing interest in recent years. The selection of new functional monomer is imorptant in molecular imprinting technique. Polymers of o-Phenylenediamine (OPDA) have two representative structures, which can generate highly cross-linked polymers. Therefore, OPDA can be used as functional monomer and cross-linker, and in this sense can have performance in analytical chemical areas, and create new opportunities. The main contents in this thesis are described as follows:1. In this paper, the molecular imprinted technology was systematically summed up. Synthetic methods of molecularly imprinted polymers and application of the molecular imprinted technology in analytical chemistry were particularly outlined. At the same time, the development of research on antioxidant was systematically inyroduced, too.2. 4-Nitrophenol and 2,4-dinitrophenol imprinted polymers were synthesized by surface imprinting technique. In the preparation, OPDA was selected as the functional monomer, silica gel was used as supper. The effects of the preparation conditions, such as the pH, the temperature, the amount of template,functional monomers and silica gel were investigated. At last, under this optimal condition, the prepared MIPs showed high adsorption capacity and significant selectivity.3. PANI nanofibers were investigated as radical scavenger. PANI nanofibers in emeraldine base form were synthesized by photo-assisted chemical oxidative polymerization of aniline. The polyaniline nanofibers with different diameters were prepared by changing the dopant acid, and the conventional polyaniline was synthesized by changing the reactants concentrations. The antioxidant activity of PANI was evaluated by determining 1,1-diphentl-2-picrylhydrazyl (DPPH) radicals scavenging ability using UV-vis spectroscopy. As long as the polymerization was performed under dilute concentrations of reactants, regular nanofibers were formed, regardless of the type of the used dopant acids. PANI nanofibers produced with different dopant acids showed similar nanofiber structures of networks, but with different diameters. At the meanwhile, the product is a mixture of fibrillar structures and irregular particles when polymerization was performed under high concentrations of reactants. The antioxidant activity of PANI is related to its diameter, and it increased as the nanofibers diameters decreased.