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采用无皂乳液聚合技术,在亚甲基双丙烯酰胺(MBA)为交联剂的情况下,N-异丙基丙烯酰胺(NIPAM)与甲基丙烯酰氧乙基三甲基氯化铵(DMC)发生共聚,生成具有阳离子功能化的热响应微凝胶poly-(NIPAM-co-DMC).TEM研究表明该微凝胶粒子的粒径约为200 nm左右,具有规则的球形形态.DLS和1H-NMR研究证实了微凝胶粒子的最低临界溶液温度(LCST)在34℃左右.进一步以此微凝胶为模板,在中性条件下,以四甲氧基硅烷(TMOS)为硅源,在此模板上仿生沉积S iO2,生成poly(NIPAM-co-DMC)/S iO2杂化纳米粒子.FTIR、TEM、1H-NMR及TGA等研究表明S iO2在聚合物模板上发生了沉积.能谱分析进一步证明了S iO2主要分布在杂化纳米粒子的壳层区域.另外,当矿化反应温度高于微凝胶的LCST值时,体系生成了具有明显核壳结构的异形杂化粒子.
Using soap-free emulsion polymerization technology, in the case of methylene bisacrylamide (MBA) as a cross-linking agent, N-isopropylacrylamide (NIPAM) and methacryloyloxyethyltrimethylammonium chloride DMC) to generate a cationically functionalized thermo-responsive microgel poly- (NIPAM-co-DMC) .TEM studies show that the microgel particles have a regular spherical morphology with a diameter of about 200 nm, And1H-NMR confirmed that the lowest critical solution temperature (LCST) of microgel particles was about34 ℃ .Then the microgels were further used as a template under the neutral condition with tetramethoxysilane (TMOS) as silicon Source, in which Si02 is generated by biomimetic deposition to generate poly (NIPAM-co-DMC) / Si02 hybrid nanoparticles. Studies on FTIR, TEM, 1H-NMR and TGA indicate that Si02 is deposited on the polymer template .Scheme analysis further proved that S iO2 mainly distributes in the shell region of the hybrid nanoparticle.In addition, when the mineralization temperature is higher than the LCST value of the microgel, the system has a heterogeneous hybridization with a distinct core-shell structure particle.