【作者】 闫立军；

【导师】 冯传良； 张治红；

【作者基本信息】 郑州轻工业大学 ， 材料学， 2010， 硕士

【摘要】 偶氮苯类化合物具有独特的光学顺反异构特性,在异构化转变过程中会伴随着一些物理化学性质的改变。目前偶氮类材料被广泛地应用于药物可控释放、非线性光学元件、液晶材料、光调控生物敏感材料等方面。本论文制备了三种含不同端基的功能化偶氮苯聚合物,并利用傅立叶红外光谱仪(FT-IR)、核磁共振波谱仪(1H NMR)表征了其结构,详细研究了牛血清白蛋白(BSA)在含偶氮苯敏感膜上的吸附行为。本课题旨在研究在光、电两种外场影响下,BSA在偶氮苯聚合物膜表面的可逆吸附机理,为进一步研究开发光敏性传感器芯片提供理论基础。首先,考察BSA在聚-4-氯-4’-偶氮苯甲基丙烯酸酯(PMAAzoCl)薄膜表面的吸附行为。通过自由基聚合法制得PMAAzoCl,并采用紫外吸收光谱(UV)详细研究该聚合物的光学异构特性,在紫外-可见光循环照射下,PMAAzoCl发生明显的异构化转变,且光响应速度较快,其光致异构反应为一阶动力学反应。接着,利用旋转涂膜技术在金片和硅片表面制备聚合物膜,并在紫外-可见光交替照射下采用接触角仪(CA)考察聚合物膜表面浸润性的变化。采用表面等离子体谐振仪(SPR)在位研究BSA在聚合物膜表面的吸附动力学,重点研究在紫外-可见光循环照射下,聚合物结构的改变对蛋白质吸附的影响。SPR测试结果显示,在该聚合物膜表面BSA分子能够发生可逆吸附。为了考察聚合物化学结构对生物分子吸附的影响,又利用表面引发原子转移自由基聚合(SI-ATRP)方法在金膜及硅片表面制备了结构规整的偶氮苯聚合物刷,即聚-4-(6-羟基己氧基)-4’-羧基偶氮苯甲基丙烯酸酯(PMAAzoCOOH)。同时合成了在金膜及硅片表面进行接枝反应所需的两种引发剂6-巯基-2-溴-2-甲基丙酸己酯及N-(3-甲氧基硅基)正丙基-2-溴-异丁酰胺,并通过FT-IR与1H NMR表征了其化学结构,然后将其组装到金片和硅片表面,采用SI-ATRP法制备偶氮苯聚合物刷。接着,采用原子力显微镜(AFM)观察聚合物刷在紫外-可见光照射前后的表面形貌变化。在此基础上,采用SPR在位考察了BSA在聚合物膜表面的动态吸附,结果表明在紫外-可见光作用下,聚合物膜同样可以实现光控可逆的BSA分子的可逆吸附。最后,为了进一步研究外场对生物分子在偶氮苯类聚合物表面的吸附行为和机理,又利用循环伏安法(CV)和SPR考察了BSA在光电双重响应性聚合物膜表面的可逆吸附行为。为了得到具有双重响应性物质,本课题把吡咯分子引入到偶氮苯取代基中,并利用化学氧化聚合法制备出聚-4-(6-羟基己氧基)-4’-羧基偶氮苯甲基丙烯酸酯聚合物(PPyAzoCOOH),采用UV详细研究了聚合物的光学异构现象,与上述两种聚合物相比,PPyAzoCOOH的光致异构速率明显变慢;同时在紫外-可见光交替照射下采用AFM观察BSA在聚合物膜表面的吸附及解吸附。利用CV测试聚合物膜的导电性能及BSA在聚合物复合电极吸附前后的电化学活性变化,运用SPR检测BSA在聚合物膜表面的可逆吸附动力学,结果表明该偶氮苯吡咯聚合物具有良好的光电响应特性。通过对三种偶氮苯类聚合物体系光学异构性的比较,可以发现,随着偶氮苯分子的柔性间隔链长的增加,光学异构速率降低,而偶氮苯类聚合物的功能基团种类和外场条件则是影响BSA吸附的主要原因。更多还原

【Abstract】 Recently, azobenzene derivatives have been intensively studied due to their trans-cis isomerization properties and the accompanied change of their physical properties. Therefore, they have been widely used in many fields, such as optical information storage materials, nonlinear optical materials, liquid crystal materials, light adjust and controlling materials of biological activity and nanophase materials. In the present work, three kinds of azobenzene-containing monomers were synthesized and polymerized to be applied as the sensitive layers for biomolecules binding. The chemical structures of them were characterized by Fourier Transform Infrared Spectroscopy (FT-IR) and Nucler Mgnetic Reonnce Spectroeter (1H NMR).Firstly, BSA adsorption on poly (4-((4-chlorophenyl) diazenyl) phenyl methacrylate), which was prepared by the method of free radical polymerization, was investigated by surface plasmon resonance of spectroscopy (SPR) in details. At the very beginning, the polymer was dissolved in the solvent. The polymer solution was dropped onto the substrates, i.e., Si or Au, and formed the polymer film. FT-IR was used to characterize the chemical structure of monomers and polymer. And the reversible photoisomerization of polymer film was studied by contact angle (CA) and UV-Vis absorption spectrum. Moreover, the reversible processes of photoisomerization of azopolymer can be induced by UV light. It suggests that the rate of photoisomerization is fast and first-order constant. Afterwards, before and after the irradiation of UV light, the adsorption kinetics of BSA on azopolymer surface was measured by SPR. The results showed that BSA molecules can be adsorbed onto the polymer film reversibly.In order to understand the effect of the polymer structure on biomolecules anchor and improve the controllable ability of biomoleucles onto the azopolymer surfaces, the grafting polymer brushes which is regular structure and narrow distribution of molecular weight was prepared on Au and silicon substrates by the method of surface-initiated atom transfer radical polymerization (ATRP). Herein, 6-mercaptohexyl 2-bromo-2-methylpropanoate and 6-(3-dimethoxy (methyl) silyl)-2-bromide-2-methyl propanamide were used as initiators and self-assembled onto Au and silicon substrates, respectively. Also, the chemical structure and photo-properties of azopolymer were characterized by FT-IR and UV. Moreover, the variations of the morphology of the surface before and after UV irradiation were measured by Atomic Force Microscopy (AFM). While as the adsorption kinetics of BSA on azopolymer surface was measured in situ by SPR. Comparing with the first azopolymer, the similar result was obtained. BSA could be adsorbed onto the polymer surface reversibly. Furthermore, BSA adsorption was also depended on the type of functional groups contained in the azopolymer chains.Aim to enhance the controllability on biomolecules anchor on polymer matrix, pyrrole group was introduced into the azobenzene molecules. Polymer (poly 4-((4-((6-(1H-pyrrol-1-yl) hexyl) oxy) phenyl) diazenyl) benzoic acid, PPyAzoCOOH) was prepared by chemical method. Therefore, the polymer synthesized will be conductive and photo-isomerized. Herein, the homopolymer was prepared and spin-coated onto the Au surfaces. Afterwards, the chemical, photo and surface properties were measured by FT-IR, UV, AFM and CA. Comparing with the former two polymers, the rate of photoisomerization of azopolymer is much slower. Cyclic voltammogram was applied to detect the electrochemical properties of azopolymer before and after BSA binding.The photo-isomerization of three azopolymers is different and depended on the spacer lengenth between azobenzene group and the backbone of polymers. The rate of isomerization of azopolymers becomes slow with the spacer lengenth increasing. Furthermore, the BSA adsorption is affected mainly by the types of the functional groups of azopolymers and the conditions of the external fields.更多还原