具有二氧化碳刺激响应性的纳米球形聚电解质刷的合成及其应用

发布时间：2018-03-19 06:39

本文选题：二氧化碳刺激响应性聚合物　切入点：纳米球形聚电解质刷　出处：《华东理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：二氧化碳作为一种新型的刺激源,不仅具有无毒易除去等特点,还是高等有机体新陈代谢的主要产物之一,同时兼具很好的生物相容性,因此研究具有二氧化碳刺激响应性的聚合物成为目前的研究热点之一。纳米球形聚电解质刷是由球形聚合物乳液微粒以及接枝在其表面的线形聚电解质链所组成的一种核-壳结构的纳米粒子,通过在表面接枝不同的高分子链,进而可以达到球形聚电解质刷的功能化,因此它在基础研究或工业应用方面均有着不俗的表现。本工作的主要内容是制备具有pH、盐离子浓度、温度以及二氧化碳的多重刺激响应性的球形聚甲基丙烯酸N,N-二甲基氨基乙酯刷(PS-DMAEMA),研究它对各种环境刺激响应性以及它用于蛋白质"吸附—脱附"过程的绿色可逆性。除此之外,还将PS-PDMAEMA作为对二氧化碳刺激响应的粒子用于稳定Pickering乳液,并使用二氧化碳调节其刺激响应性。本文的主要工作和相应的研究结论如下:(1)利用光乳液聚合法合成纳米球形聚电解质刷:以聚苯乙烯(PS)作为球核,接枝带有叔胺基团的聚甲基丙烯酸N,N-二甲基氨基乙酯(DMAEMA)链,研究该纳米粒子PS-PDMAEMA在水相中的pH、盐离子和温度的多重敏感性;并且,将PS-PDMAEMA用于固载牛血清蛋白(BSA),使用动态光散射(DLS)、zeta电位、浊度以及等温量热仪(ITC)进行吸附效果的表征。研究表明PS-PDMAEMA是一种很好的蛋白质载体,具有很强的吸附能力,并且可以通过pH、盐离子和温度调节聚合物刷的粒径尺寸以及对蛋白质的吸附效果。(2)在前面的工作基础上,继续研究了球刷PS-PDMAEMA对二氧化碳的刺激响应性以及对蛋白质的可逆"吸附-脱附"过程:在PS-PDMAMEA体系中通入二氧化碳后,可以使得PDMAEMA链质子化,呈现舒展的状态,球刷的粒径变大,随后,通入惰性气体(如氮气或氦气)后,PDAMEAM链去质子化,分子链收缩,粒径会回复至初始状态,经过多次可逆循环后仍能保持该性质并且也不会给体系留下任何多余的组分,因此,以"氮气/二氧化碳"作为开关,可以实现PS-PDMAEMA对蛋白质的可逆"吸附-脱附",结果表明该过程对蛋白质的生物活性影响很小,也不会产生盐离子浓度的积累。因此,可将其作为蛋白质的载体,完成蛋白质的分离和富集。(3)Pickering乳液是一类将固体颗粒作为稳定剂吸附于油水两个不相容的界面上并形成稳定的乳液。PS-PDMAEMA作为Pickering乳液的一种可二氧化碳调控的乳化剂:该乳化剂(PS-PDMAEMA)可使用pH、二氧化碳/氮气调节其乳化能力。本文分别从PS-PDMAEMA的浓度、体系的pH值探讨了该乳化剂的乳化效果,在光学显微镜的研究表明:当PS-PDMAEMA作为乳化剂时,需要达到一定的浓度才可以得到稳定的乳液,体系的pH会严重影响乳液的稳定性,pH过低会使得乳液发生破乳现象。除此之外,该乳化剂还可以使用二氧化碳/氮气可逆调控其乳化性能。
[Abstract]:As a new stimulant, carbon dioxide is not only nontoxic and easy to remove, but also one of the main metabolites of higher organisms, and also has good biocompatibility. Therefore, the study of carbon dioxide responsive polymers has become one of the research hotspots. Nano-spherical polyelectrolyte brushes are composed of spherical polymer emulsion particles and linear polyelectrolyte chains grafted on their surface. Of a core-shell structure, The functionalization of spherical polyelectrolyte brushes can be achieved by grafting different polymer chains on the surface, so it has a good performance in basic research and industrial application. The main content of this work is the preparation of pH, salt ion concentration, PS-DMAEMAMAA, a spherical polyN-dimethylaminoethyl methacrylate brushes with multiple stimuli response to temperature and carbon dioxide, to study its response to various environmental stimuli and its green reversibility for protein "adsorption-desorption" processes. PS-PDMAEMA was also used to stabilize the Pickering emulsion as a particle responsive to carbon dioxide stimulation. In this paper, the main work and corresponding conclusions are as follows: the photoemulsion polymerization method is used to synthesize nano-spherical polyelectrolyte brushes: PS) is used as the spherical nucleus. Grafted poly (N-dimethyl aminoethyl methacrylate) chain with tertiary amine group was used to study the pH, salt ion and temperature sensitivity of the PS-PDMAEMA nanoparticles in aqueous phase. PS-PDMAEMA was used to immobilize bovine serum protein (BSA). The adsorption effect of BSA was characterized by dynamic light scattering (DLS), turbidity and isothermal calorimeter. The results show that PS-PDMAEMA is a good protein carrier and has strong adsorption ability. In addition, the particle size of polymer brush and the adsorption effect of protein can be adjusted by pH, salt ion and temperature on the basis of the previous work. The reactivity of PS-PDMAEMA to carbon dioxide and the reversible "adsorption-desorption" process of protein were studied. When carbon dioxide was added into the PS-PDMAMEA system, the PDMAEMA chain could be protonated, showing a stretch state, and the particle size of the spheroidal brush became larger. Subsequently, the PDAMEAM chain is deprotonated with inert gas (such as nitrogen or helium), the molecular chain shrinks, the particle size returns to its initial state, and the property remains after several reversible cycles without leaving any extra components in the system. Therefore, using "nitrogen / carbon dioxide" as switch can realize the reversible "adsorption-desorption" of protein by PS-PDMAEMA. The results show that the process has little effect on the biological activity of protein and does not result in the accumulation of salt ion concentration. They can be used as carriers of proteins, Complete protein separation and enrichment. Pickering emulsion is a kind of stable emulsion. PS-PDMAEMA is a kind of Pickering emulsion which adsorbs solid particles as stabilizer on the interface of oil and water and forms stable emulsion. PS-PDMAEMA is a kind of emulsifier that can be controlled by carbon dioxide in Pickering emulsion. The emulsifier PS-PDMAEMAA can use pH, carbon dioxide / nitrogen to adjust its emulsifying ability. The emulsifying effect of the emulsifier was discussed by pH value of the system. The results of optical microscope showed that when PS-PDMAEMA was used as emulsifier, a stable emulsion could be obtained only when the emulsifier reached a certain concentration. The pH of the emulsion will seriously affect the stability of the emulsion. Too low pH will lead to the emulsion demulsification. In addition, the emulsifier can be used to control the emulsifying performance of the emulsion by using carbon dioxide / nitrogen.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631;TB383.1

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