Novel Temperature Sensitive Copolymeric Hydrogels

Hydrogel with three-dimensional net structure was one of the most widely performance form of stimuli-responsive polymers that can exhibit abrupt physical or chemical property changes in response to changes in external stimuli,as its wide application prospect in drug releasing. artificial muscles, enzyme immobilization, tissue and biomedical engineering and so many fields.Poly(N-isopropyl acrylamide)(PNIPAm),as a typical temperature sensitive hydrogel.to be match for actual application preferably to require that the hydrogel had a the critical solution temperature(LCST) close to the body temperature(37℃).quick response speed,diversified response mode and non-toxic to atmosphere.In this thesis. N-isopropyl acrylamide(NIPAm) was used to copolymerized with 2-hydroxyethyl acrylate.and by adding polyethylene glycol(PEG)as pore-forming agent to prepare temperature sensitive type gel with porous structure.While the mass ratio of NIPAm and 2-hydroxyethyl acrylate was 9:1,the LCST was improved from 33.7℃to 35.08℃.The LCST of copolymerized hydrogel could be controllable through regulating the reactant ratio. And the response rate would be accelerated from the increase of M.w. and dosage of PEG. While increasing the concentration of monomers and crosslinking agent reduced the balance swelling ratio(SR),and increased the swelling/back dynamics effectively.According to azo functional group as a light-operated unit, a kind of azobenzene-containing monomer, EAPEA was synthesized.CAPA and CAPEA containing carboxyl in terminal group were synthesized to improve hydrophilicity of azo monomers. Then a novel water-soluble azo monomer DMAE-EAPB4 was designed and synthesized due to that stationary substituent of CAPA and CAPEA led to simplex response mode. The photoinduced temperature response gels are produced by direct copolymerization of NIPAm with azobenzene-containing monomers in equal molar ratio(1:100).The LCST of hydrogel reduced on different degree. while 4.66℃for P(NIPAm/DMAE-EAPB4).3.76℃for P(NIPAm/CAPA)and 7.92℃for P(NIPAm/CAPEA).Upon UV irradiation the LCST of hydrogel copolymerizated with DMAE-EAPB4 increased 1.96℃compared with CAPA. CAPEA for about 0.6℃.The result indicated that azo monomer with strongly polar quaternary ammonium had a vastly improving in surface hydrophilicity.faster ultraviolet response speed and could realize the diversity of response mode to replacing the type of substituent group.DMAE-BC as a typical cationic fungicide.was directly copolymerizate with NIPAm to obtain a kind of temperature sensitive gel in consideration of preventing microbe infection. The antibacterial property was discussed from against Escherichia coli. The conclusion was expected to be cornerstones for its application in more fields,especially bio-medical field.