聚苯乙烯—聚（4-乙烯基吡啶）嵌段共聚物LB膜结构形态的研究

发布时间：2018-03-25 10:18

本文选题：嵌段共聚物　切入点：聚苯乙烯-聚(4-乙烯基吡啶)　出处：《东华大学》2017年硕士论文

【摘要】：两亲性嵌段共聚物具有独特的微观相分离行为,类似于小分子表面活性剂,能够铺展于液体表面,因此两亲性嵌段共聚物的Langmuir-Blodgett薄膜(LB膜)受到了广泛的关注。通过微观区域结构的调控,可以制备出高度有序排列、尺寸均一的纳米薄膜。LB膜丰富的结构形态和聚集组装行为也一直是研究的热点和难点。本文利用Langmuir-Blodgett技术(LB膜技术)和原子力显微镜(AFM)分别对嵌段共聚物聚苯乙烯-聚(4-乙烯基吡啶)(PS-b-P4VP)的结构形态及嵌段共聚物聚苯乙烯-聚(4-乙烯基吡啶)/1-芘丁酸(PS-b-P4VP/PBA)共混体系的结构形态进行了研究。采用氯仿作为铺展溶剂,将PS-b-P4VP和PS-b-P4VP/PBA稀溶液铺展于空气与水界面上,待溶剂挥发,研究PS-b-P4VP和PS-b-P4VP/PBA的单分子层聚集体结构和LB膜形貌。本论文具体研究了不同嵌段比和表面压对PS-b-P4VP的等温曲线和LB膜的表面形态的影响,以及小分子1-芘丁酸(PBA)的加入和浓度的变化对PS-b-P4VP/PBA体系结构形态的影响。通过对Langmuir单分子层π-A等温曲线和LB膜原子力显微镜图像的分析,PS-b-P4VP体系中发现随着亲水段(P4VP)的增加,π-A等温曲线向右移动,平均每分子占有面积增加,嵌段共聚物在被压缩的过程中出现更多更丰富的结构形态;LB膜形貌也随着P4VP含量的变化而变化,薄膜形貌由初始的纳米片状、带状结构转变成纳米条状、纳米点状结构,膜厚随着P4VP含量的增大而减小。表面压对纯的PS-b-P4VP聚集组装结构产生很大的影响,表面压增大,聚集体排列变得紧密;随着表面压的继续增大,单层聚集结构遭到破坏,分子发生堆叠,形成两层或两层以上的结构。在PS-b-P4VP中加入PBA小分子后,PBA与PS-b-P4VP间氢键的形成,对亲水段较大的单分子层π-A曲线影响较大,曲线向右移动,平均每分子占有面积增加;加入PBA后聚集体形态也发生明显的变化,原来的片状结构转变为条状结构或棒状结构,这与增加P4VP含量效果一致。随着PS-b-P4VP/PBA体系浓度的增大,共混物体系LB膜形貌从棒状结构逐渐变为规整的点状结构,形貌趋于规整。
[Abstract]:Amphiphilic block copolymers exhibit unique microscopic phase separation behaviors, similar to those of small molecular surfactants, and can be spread over liquid surfaces. Therefore, the Langmuir-Blodgett films of amphiphilic block copolymers have attracted wide attention. The rich structure, morphology and assembly behavior of homogeneous nano-films. LB films have also been a hot and difficult point in the study. In this paper, block copolymers polystyrene were prepared by using Langmuir-Blodgett technique and atomic force microscope (AFM), respectively. The structure and morphology of poly (4-vinylpyridine) PS-b-P4VP) and the structure and morphology of block copolymers PS-b-P4VP- PBA- PS-b-P4VP- PBA-) were studied. The dilute solution of PS-b-P4VP and PS-b-P4VP/PBA was spread on the interface between air and water, and the solvent was volatilized. The structure of monolayer aggregates and the morphology of LB films of PS-b-P4VP and PS-b-P4VP/PBA were studied. The effects of block ratio and surface pressure on the isothermal curves of PS-b-P4VP and the surface morphology of LB films were studied. The effects of the addition and concentration of 1-pyrene butyrate on the structure and morphology of PS-b-P4VP/PBA system were also discussed. By analyzing the isothermal curve of Langmuir monolayer 蟺 -A and the atomic force microscope image of LB film, it was found that PS-b-P4VP system with hydrophilic segment P4VP). The 蟺 -A isothermal curve moves to the right. The average occupied area of each molecule increased, and the morphology of block copolymers changed with the change of P4VP content, and the morphology of block copolymers changed from the initial nano-flake. The film thickness decreases with the increase of P4VP content. The surface pressure has a great effect on the pure PS-b-P4VP aggregation and assembly structure, the surface pressure increases and the aggregate arrangement becomes tight. With the increasing of the surface pressure, the monolayer aggregation structure was destroyed, and the molecules were stacked to form two or more layers of structure. The hydrogen bond between PBA and PS-b-P4VP was formed after the addition of small PBA molecules in PS-b-P4VP. The 蟺 -A curve of monolayer in hydrophilic segment is greatly affected, the curve moves to the right, and the average area per molecule increases, and the morphology of aggregates also changes obviously after adding PBA, and the original lamellar structure is transformed into stripe structure or bar structure. With the increase of the concentration of PS-b-P4VP/PBA, the morphology of LB films of the blends gradually changed from rod-like structure to regular point structure, and the morphology tended to be regular.
【学位授予单位】：东华大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O631;TB383.2

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