【作者】 苏晨；

【导师】 邵伟；

【作者基本信息】 南京林业大学 ， 应用化学， 2020， 硕士

【摘要】 本论文旨在构造多重响应性凝胶材料。主要以N-异丙基丙烯酰胺（NIPAM）单体,采用物理交联和传统化学交联法,分别制备微凝胶和水凝胶,并对其化学结构、微观形貌、力学性能、敏感性能、光学性能等进行表征和测试分析。具体内容如下:（1）采用水热法通过埃及橙制备荧光碳点（CDs）,并通过自由基沉淀聚合法制备CDs@P（NIPAM-DMAEA-MAAC）微凝胶,最后将苯硼酸（PBA）基团接枝到微凝胶主链上以制得CDs@P（NIPAM-DMAEA-PBA）微凝胶。红外光谱（FTIR）和X射线光电子能谱（XPS）结果表明:荧光碳点表面及内部富含大量羧基、羰基等含氧官能团;荧光发射光谱结果表明:碳点溶液具有很强的激发依赖性质,当激发波长设定为363 nm时,其在448 nm处出现最大强度发射峰。荧光猝灭测试结果表明:Fe³⁺对碳点溶液具有最大的荧光猝灭效果;DLS数据结果表明:微凝胶具有显著的温度敏感性、葡萄糖敏感性和生理pH范围内的pH敏感性;荧光光谱曲线结果表明:微凝胶与葡萄糖结合的诱导效应引起的构象变化进一步影响碳点溶液的光致变色行为,在葡萄糖浓度0-20 mM区间范围内,荧光强度变化率与浓度关系呈现正相关性,且线性拟合度高。（2）采用非金属掺杂的方式制备氮掺杂二氧化钛（N-TiO₂）,并通过自由基聚合法制备N-TiO₂/PNIPAM复合水凝胶。首先对掺杂改性后获得的N-TiO₂的化学结构和微观形貌进行表征分析。其次对N-TiO₂/PNIPAM复合水凝胶的化学结构、形貌特征、热稳定性等进行表征分析以及其对有机物吸附降解和抑制细菌生长性能进行评估。结果表明:N-TiO₂由锐钛矿相构成,氮掺杂改性没有改变TiO₂的晶体结构;通过基于氮掺杂二氧化钛的光催化,N-TiO₂/PNIPAM复合水凝胶在可见光下对亚甲基蓝（MB）成功降解并脱色;抑菌测试结果表明复合水凝胶在可见光照下对大肠杆菌（E.coli）,白色念珠菌（C.albicans）和金黄色葡萄球菌（S.aureus）均表现出良好的抑菌性能,具有广阔的实际应用前景。（3）通过自由基聚合制备温度和pH双重敏感性的γ-PGA/PNIPAM复合水凝胶,并采用溶液浸泡法制得负载阿莫西林的载药复合水凝胶。FTIR、扫描电子显微镜（SEM）、孔隙率和热重（TG）结果表明:复合水凝胶成功制备,且模型药物阿莫西林成功负载,复合水凝胶内部呈现均匀的三维孔隙结构,γ-PGA组份的掺入使得水凝胶体系的热稳定性略微下降;DSC、透光率、压缩性能和溶胀分析结果表明:复合水凝胶的LCST值升高,透光率维持在0%,具有优异的回弹能力;溶胀结果表明,复合水凝胶表现出优异的温度敏感性和pH敏感性;抑菌测试结果表明:载药复合水凝胶对E.coil、S.aureus、C.albicans和枯草芽孢杆菌（B.subtilis）均具有良好的抑菌效果,具有良好的生物医用前景。（4）以粘土为交联剂并通过自由基聚合制备温度、pH和无机盐三重敏感性PNIPAM/CMC复合水凝胶。在实现多重敏感性的同时,通过引入模型药物TCH构建载药复合水凝胶,并评估其抗菌效果。FTIR、TG、SEM等分析表明:复合水凝胶具有三维多孔网状结构,CMC的含量对复合水凝胶的热稳定性和内部孔洞形状未造成明显的影响;压缩性能测试与流变性能分析结果表明:当CMC的添加量为NIPAM单体质量的5%时,力学性能处于更佳状态;溶胀性能测试结果表明:随着CMC添加量的增加,复合吸水溶胀能力增强,且表现出优异的温度敏感性,pH敏感性和无机盐敏感性;抑菌测试结果表明:载药复合水凝胶对E.Coli和B.subtilis均具有优异的抗菌效果,具有良好的生物医用前景。更多还原

【Abstract】 This paper aims to construct multifunctional gel materials.Using N-isopropylacrylamide（NIPAM）and physical cross-linking and traditional chemical cross-linking methods to prepare microgels and hydrogels.The chemical structure,micro-morphology,mechanical properties,sensitive properties and optical properties of the gels were characterized.The details are as follows:Firstly,fluorescent carbon dots（CDs）were prepared from Egyptian orange by hydrothermal method,and CDs@P（NIPAM-DMAEA-MAAC）microgels were prepared by free radical precipitation polymerization method.CDs@P（NIPAM-DMAEA-PBA）microgels were prepared by grafting phenylboronic acid（PBA）group onto the main chain of microgel.Infrared spectroscopy（FTIR）and X-ray photoelectron spectroscopy（XPS）show that the surface and inside of the fluorescent carbon dots are rich in a large number of oxygen-containing functional groups such as carboxyl groups,amino groups,and carbonyl groups.The results of fluorescent emission spectra show that the carbon dot solution has strong excitation-dependent properties,when the excitation wavelength is set to 363 nm,its maximum intensity emission peak appears at 448 nm.Fluorescence quenching test results show that Fe³⁺has the greatest fluorescence quenching effect on carbon dot solution.DLS data results show that microgels have significant temperature sensitivity,glucose sensitivity and pH sensitivity in physiological pH range.The results of the fluorescence spectrum curves show that the conformational change caused by the induction effect of the combination of the microgel and glucose affects the photochromic behavior of the carbon dot.When glucose concentration is in the range of 0-20 mM,the relationship between the change rate of fluorescence intensity and the concentration showed a positive correlation and a high linear fit.Secondly,N-doped TiO₂ was prepared by doping non-metal ions,and N-doped TiO₂/PNIPAM composite hydrogel was prepared by free radical polymerization.First,the chemical structure and micro-morphology of obtained N-doped TiO₂ after doping modification were analyzed.Next,the chemical structure,morphology,and thermal stability of the N-doped TiO₂/PNIPAM composite hydrogel were characterized and analyzed,as well as its abilities to adsorb and degrade organic matter and antibacterial growth were evaluated.The results show that N-doped TiO₂ is composed of anatase phase,and the doping modification of non-metallic ions does not change the crystal structure of TiO₂.Methylene blue（MB）can be successfully decolorized and degraded by photocatalysis based on N-doped TiO₂ at room temperature.Composite hydrogel exhibits good antibacterial properties against E.coli,C.albicans and S.aureus,and has broad practical application prospects.Thirdly,the temperature and pH-sensitiveγ-PGA/PNIPAM composite hydrogel was successfully prepared by free radical polymerization,and amoxicillin-loaded composite hydrogel was prepared by the solution immersion method.FTIR,scanning electron microscope（SEM）,porosity and thermogravimetric（TG）results show that the composite hydrogel is successfully prepared,and the model drug amoxicillin is successfully loaded.The composite hydrogel presents a uniform three-dimensional pore structure.The incorporation of the PGA slightly reduced the thermal stability of the hydrogel system.DSC,light transmittance,compression performance,and swelling analysis results show that the LCST value of the composite hydrogel increases and the light transmittance remained at 0%.It has excellent resilience.The swelling results show that the composite hydrogel shows excellent temperature sensitivity and pH sensitivity.The antibacterial test results show that the drug-loaded composite hydrogel has good antibacterial effect on E.coil,S.aureus,C.albicans and B.subtilis,and has good biomedical prospects.Finally,PNIPAM/CMC composite hydrogel with triple sensitivity of temperature,pH and inorganic salt is prepared using clay as cross-linking agent.While achieving multiple sensitivities,the drug-loaded composite hydrogel was constructed by introducing model drug TCH,and its antibacterial effect was evaluated.FTIR,TG,SEM and other analysis show that the composite hydrogel has a three-dimensional porous network structure,and the content of CMC has no obvious effect on the thermal stability and internal pore shape of the composite hydrogel.Compression performance test and rheological performance analysis results show that when the amount of CMC added is 5%of the mass of NIPAM monomer,the mechanical properties are in a better state.The swelling performance test results show that as the amount of CMC added increasing,the swelling ability is enhanced,and it exhibits excellent temperature sensitivity and pH sensitivity.Antibacterial test results show that the drug-loaded composite hydrogel has excellent antibacterial effect on E.Coli and B.subtilis,and has good biomedical prospects.更多还原