Synthesis, Characterization And Properties Of Stimuli-Responsive Of Polymers And Hydrogels With The Triazole Groups

In this thesis, several types of stimuli-responsive polymers and hydrogels were synthesized by radical solution polymerization using acrylic acid (AA) and N,N-diethylacrylamide (DEA), respectively, as pH- and temperature- sensitive monomers. The products were characterized by FTIR, ~1H NMR and SEM, and the pH, temperature, metal ion and salt-sensitivity of them were investigated. The main conclusions were drawn as follows:1. A novel salt- and pH-responsive copolymer, Poly (acrylic acid-co-ethyl 1 -(4-chlorophenyl)-5-acrylamino-1,2,3-triazol-4-carboxylate), Poly(AA-co-ECATC), was prepared and characterized. The copolymer possessed excellent fluorescence properties due to the introduction of ECATC, and it was employed to study the conformation transition of copolymer chains in solutions. The effects of metal ions with different charges, radius and outer-layer electron constructions and pH values of the medium on the conformation transition of copolymer chains were systematically investigated by the fluorescence intensity and the fluorescence anisotropy. It was found that fluorescence intensity and fluorescence anisotropy curves waved with the change of metal ions concentrations and pH values. The waved curves result from the change of coordination numbers between metal ions and the copolymer. Additionally, FTIR Subtraction spectroscopy was also carried out to confirm the results. The work provided a theory basis for the study of salts- and pH-sensitive smart hydrogels, which were always used in the slow- or controlled-release drugs.2. An interpenetrating polymer network comprised of poly (acrylic acid) (PAA) and triazole modified poly (vinyl alcohol) (TMIPN) was synthesized and characterized. The behaviors of swelling / deswelling and the controlled release in vitro were studied, respectively, in different pH, concentrations of NaCl and physical stimulus in aqueous solutions. The results showed that the TMIPNs hydrogels had excellent pH- and salt-sensitivity in the range of the investigation.3. A series of interpenetrating polymer networks (TMIPNs) comprised of P(AA-co-DEA) and TMPVA (PVA modified by triazole) were synthesized and characterized. The behaviors of swelling / deswelling of hydrogels and the controlled release in vitro were investigated. The results showed that: (1) the TMIPNs hydrogels had excellent pH- and salt-sensitivity, and pH and salt dependent swelling / deswelling reversibility in the range of the investigation; (2) the behavior of controlled release of the TMIPNs hydrogels had temperature, salt concentration and pH-sensitivity.4. A novel interpenetrating polymer network (IPN) hydrogel was prepared to recognize l-(4-methoxyphenyl)-5-methyl-l,2,3-triazol-4-carboxylic acid (MMTCA), by molecularly imprinted method, in the mild aqueous media of PVA and PAA. The effects of pH values on the adsorption of MMTCA and the selectivity in the mixture aqueous solution were discussed. The experiment results suggested that the MMTCA-imprinted polymer behaved pH-sensitivity and excellent selectivity for the target molecule and the reproducibility. This research expanded the scope of applications of polymeric hydrogels about biomimetic MMTCA recognition in molecularly imprinted polymer (MIP) networks, which may also be employed in biosensor applications, especially in quantitative MMTCA monitoring.5. A new interpenetrating polymer network (IPN) hydrogel was prepared to recognize the triazole compound EAETC, by molecularly imprinted method, in the mild aqueous media of PVA and P(AA-co-DEA). The investigation of the adsorption behavior of MIP-IPN was carried out. It could be found that the adsorption capacities of MIP-IPN were much higher than those of compared hydrogels at the tested concentrations. The effects of pH values on the adsorption of EAETC were discussed and the experiment results suggested that the adsorption of the MIP-IPN had pH- sensitivity. The imprinted ratio of the MIP-IPN was investigated. The results showed that the max adsorption was made when the imprinted ratio was 20:1. The production of polymers with special functions could be used in many areas, such as drug release matrices, separation materials, molecular recognition materials for biosensors, highly specific catalysts, and antibody mimics.