【作者】 邢力；

【导师】 陈欢林；

【作者基本信息】 浙江大学 ， 生物化工， 2007， 硕士

【摘要】 本文以聚偏氟乙烯（PVDF）为膜材料，分别通过干法和浸没沉淀法制备得到新型网络状结构微孔膜。该PVDF膜由于其独特的无皮层和网络状孔径结构，具有极强的蛋白质吸附能力，可以作为蛋白质转印膜。在干法制膜方面，以N，N-二甲基乙酰胺（DMAc）作为溶剂，考察了成膜环境温度和湿度对膜结构的影响。在45℃和相对湿度（RH）为90％的情况下，能够得到无表面皮层的网络状结构膜；蒸发气氛中溶剂组分的增加能够进一步消除背面皮层结构。以上实验表明成膜过程中固化作用是通过凝胶和结晶的竞争机制而实现。进一步考察添加剂对成膜结构的影响，最终以LiCl作为添加剂制得高蛋白吸附量PVDF膜，吸附量达到150μg·cm^-2。在湿法制膜方面，采用两步凝胶浴法制备PVDF膜，研究了多种成膜条件对膜结构与性能的影响。以磷酸三乙酯（TEP）为溶剂，所成膜断面指状孔消失，形成网络状孔。PVDF的分子量对成膜过程中结晶存在很大影响，相对于低分子量PVDF而言，高分子量PVDF更易产生球状结晶。预蒸发易产生致密皮层结构，不适合制备转印膜。第一凝胶浴中，随TEP浓度的增加，表面致密层逐渐消失：而随反应时间的延长，平均孔径逐渐增大。SEM和XRD结论表明，两个凝胶浴温度的降低都能减小孔隙率，并使成膜晶型从α晶型转化为以β晶型为主的结晶结构，提高了蛋白质吸附能力。证明了液液分相对最终所成膜结构结构起决定性作用，而固化作用则改变结晶度和晶型。对添加剂而言，与TEP相溶性较好的添加剂成膜孔隙率大，并且得到了网络状结构膜，蛋白质的吸附量更大。对成膜进行了蛋白质电泳转印测试，转印主要条带清晰，与美国Millipore公司商品膜转印结果相比较产品相似；表明所制PVDF微孔膜具有着良好的转印效果。更多还原

【Abstract】 In this dissertation, symmetric poly-（vinylidene fluoride） （PVDF） membranes were prepared both by dry-cast process and immersion-precipitation process, which have the unique structure of net-shape without dense skin layer. Therefore it could be used as protein-blotting membranes for its strong non-specific adsorption ability of protein.First, the membranes formation containing PVDF/N,N-Dimethylacetamide （DMAc） by dry-cast process was studied. Membrane morphologies from crystalline polymers were found to be strongly dependent on the evaporation temperature and relative humidity. The net-shaped membrane without the dense skin layer on the air surface were obtained at the temperature of 45℃ and relative humidity （RH=90）.By adding gasified DMAc in the evaporation atmosphere, the skinless membrane could be ulteriorly gained. The results indicated that the solidification of the membrane could be achieved through the competition of gelation and crystallization. The effect of the addictives on the membrane formation was further investigated. By adding LiCl in the cast solution, the membrane prepared can have an adsorption of protein for 15μg·cm^-2.Secondly, the membranes formation containing PVDF/Triethyl phosphate （TEP） by immersion-precipitation using two successive coagulation baths was studied. In this system, the net-shaped pores replaced the finger-like pores. It was found that the morphology of PVDF membranes was greatly influenced by its molecular weight. The global crystal disappeared with PVDF of lower molecular weight. Dense layer would appear using pre-evaporation process, indicating it’s not a proper process to prepare protein-blotting membrane. The dense layer disappeared with the increase of TEP concentration in the firstTEP/water bath, and extending of the reaction time leads to the increased mean pore diameter. Low temperature of two baths tend to decrease the porosity of membranes and turn crystal type from a form to β form, which can greatly enhance the adsorption ability of protein. The study above indicated that liquid-liquid demixing takes place early and determined the final structure of PVDF membrane, whereas solidification of the membrane determined the overall crystallinity and crystal type of PVDF membranes.The PVDF membrane obtained by immersion-precipitation was tested in western-blotting application and reveals a good result which is similar to that of PVDF membrane produced by Millipore Company.更多还原