【作者】 王景雪；

【导师】 杜祖亮；

【作者基本信息】 河南大学 ， 凝聚态物理， 2004， 硕士

【摘要】 利用LB技术来构造纳米结构有序功能体系，以发展各种应用于高新技术领域的新型高性能纳米结构材料，已成为LB技术发展的主要方向。为了研究膜结构对其组装功能的影响，科学家近期对单分子膜的微结构倍加关注，并取得了重要进展。本论文涉及到以下几个方面的工作： 1、用XRD和原子力显微镜的接触模式研究了不同BA／SA配比的21层混合LB膜的分相和微结构以及膜的质量。结果发现，对于SA／BA混合膜，分相小而均匀，不出现单独的衍射周期；随比例不同，纵向面间距出现台阶效应，表明存在3类结构，其中在较大比例范围内出现了长短链交错的结构，这种结构具有高的稳定性和有序性；在BA较多的混合膜中，在脂链层间出现空洞结构，可以用来构造特殊的纳米结构。衍射强度出现“W”形状变化，表明在中间比例所形成的长短链交错的结构向两边变化时，都要经历混合膜有序度降低的过程。这为制备复合膜时比例的选取，提供了有意义的数据。 2、利用π-A等温曲线和原子力显微镜的轻敲模式对从纯水亚相上提拉的不同生物分子二肉豆蔻酰磷脂酰胆碱(DMPC)、胆固醇(Chol.)和神经鞘磷脂(Sph)不同种纯的、二元及三元混合单分子膜-LB膜和LS膜体系的相分离和微结构进行了研究。 3、聚乙烯亚胺(PEI)是一种阳离子型的聚合物，由于它在动植物细胞内优良的转染效率，而被广泛的应用，并且在生理环境下(PH＜9)它具有很强的缓冲能力。在本章中我们用这种极易溶于水的阳离子型聚合物PEI为一软垫，研究以此软垫为基底的不同生物分子和它们不同种二元及三元混合单分子膜体系在含PEI亚相上的相结构情况，初步的讨论了它们以云母为基底的IS膜和LB膜的微结构或者说是该软垫对单分子膜微结构的影响。结果发现成膜分子与软垫之间存在着强烈的相互作用，PEI的存在使得单分子膜的存在状态与纯水亚相上的单分子膜相比发生了很大的变化，形成了图案化的拓扑结构。更多还原

【Abstract】 The Langmuir-Blodgett (LB) technique has been shown to be a powerful and convenient method for molecular assembly and also been found wide application in fabricating ordered functional structures at nanometer scale to get some new type devices with fine properties. In order to study the interplay between the control of special structure and the modulation of the special functions, scientists recently have paid much attention to the microstructure of the films and have made some great progress in this field. Based on this, the abstract of my work is shown following:1. X-ray diffraction (XRD) technique was used to investigate the phase-separation and microstructure of the BA/SA mixed multilayers. The results showed that the interplanar spacing D values and relative X-ray diffraction intensity of the mixed LB films change with the ratio of BA/ SA in a step- and W- shaped curve respectively, which indicates that only three kinds of longitudinal periodic structures can form in the mixed multilayer LB films of all ratios and each microstructure can be maintained in a certain ratio range. Furthermore the mixed system always goes through a process of the longitudinal regularity decreasing when the ratio of BA/SA is out of the intermediate ratio range (BA/SA: 1/5 ~ 1/1). Tilted BA clusters are embedded in SA when BA/SA is below 1/9. Longer and shorter chain domains mesh with each other when BA/SA = 1/7 ~ 1/1, especially when BA/SA = 1/5 ~ 1/1, this "meshed structures" are much ordered and stable, therefore they may have fine mechanical property. When BA/SA = 3/1 -9/1, longer domains (BA) are in majority, and some hydrophobic "holes" (caused by the difference in height between BA and SA) formed in the alkyl layer which can be used to fabricate special functional nanostructures. Those conclusions may be meaningful for us to determine mixture ratio when fabricating composite films with special structures.2. We study the phase-separation and microstructure of the pure binary and trinary mixed LB and LS films of Dimyristoyl phosphatidyicholine (DMPC) cholesterol(Chol )and sphingomylin(Sph) deposited from pure water subphase by π-A isotherms and tapping mode Atomic Force Microscopy.3. Polyethylenimine(PEI),a water-soluble cationic polyelectrolyte , has been extensively used as a deformable and mobile substrate for a biomembrane for it high transfection efficiency of chemical-based delivery systems. What’s more, PEI is good buffer in physiological environment (PH<9). We used this water-soluble cationic polyelectrolyte PEI as a soft cushion for biomimetic membranes in this chapter, and studied the microstructure of polymer-cushioned pure binary and trinary mixed LB and LS films of Dimyristoyl phosphatidyicholine (DMPC) . cholesterol(Chol )and sphingomylin(Sph) ( that is to say study the influence of PEI cushion on the microstructure of the monolayers) deposited from lOOppm PEI water solution subphase by π-A isotherms and tapping mode Atomic Force Microscopy. Results revealed that there are strong interactions between spreading molecules and PEI soft cushion, and PEI’s existing made the microstructure of the monolayers very different from that of the films deposited from pure water subphase, and surface patterned topography formed. But when the mixure ratio of the film is similar to that of actual biomembrane, their topographies are almost the same as that of the special films deposited from pure water subphase, so such mixed films deposited from the 100ppm PEI water solution subphase, can be used to study their thermodynamic properties.更多还原