DPPC与MMA混合单层LB膜缺陷结构的AFM研究  

Atomic Force Microscopy Study of Defective Structure in Mixed Langmuir-blodgett Film of Dipalmitoylphosphatidylcholine and Methylmethacrylate

作　　者：许小晶[1] 邓穗平[1] 郑辉[1] 蔡继业[1] 欧阳健明[1] 

机构地区：[1]暨南大学生物矿化与结石病防治研究所,广州510632

出　　处：《人工晶体学报》2008年第1期43-48,共6页Journal of Synthetic Crystals

基　　金：国家自然科学基金(No.20471024);教育部留学回国人员科研启动基金(教外司[2005]55号)

摘　　要：采用原子力显微镜（AFM）研究了转移到疏水石英基片上的二棕榈酰磷酯酰胆碱（DPPC）与不同浓度聚合物单体分子甲基丙烯酸甲酯（MMA）的混合物所形成的单层LB膜及其缺陷的微结构,研究了沉积压对缺陷的影响。当MMA的摩尔比为33%（即MMA∶DPPC=1∶2）,沉积压为5.0mN/m时,生成直径约3～4μm的圆形液态凝聚相（LC）畴区,LC畴区主要为DPPC与MMA的混合物,同时还分布着一些由聚合的MMA分子（即聚合物PMMA）形成的“小岛”;当沉积压增加至15.0mN/m时,LC畴区中主要为聚合物PMMA的聚集体。当MMA的摩尔比增加至50%后,LC畴区中聚合物PMMA含量增加。畴区产生的主要原因是由于不同MMA含量和沉积压使DPPC和MMA及其聚合物PMMA产生不同程度的相分离所致。MMA/DPPC混合LB膜中这种圆形的畴区缺陷可以诱导形成圆形的一水草酸钙晶体沉积图形。The contacting-mode atomic force microscopy （AFM） was used to investigate the microstructure of the mixed Langmuir-blodgett （ LB ） film of methylmethacrylate （ MMA ） and 1,2- dipalmitoyl-sn-glycero-3-phosphocholine （DPPC） deposited on hydrophobic quartz substrate. The defects in the LB film and the effect of deposited pressure on the defects were studied. The results revealed that monomer MMA could be congregated in the LB film. When MMA： DPPC = 1 ： 2 and the deposited surface pressure of 5.0mN/m, liquid-condensed （LC） phase coexisted with liquid-expanded （LE） phase. The LC domains, composed of mixtures of DPPC and MMA, were observed with a diameter of approximately between 3μm and 4μm. And some islands （polymerized MMA aggregation） distributed in the LC domains. While the deposited surface pressure of 15.0mN/m, islands of the polymethylmethacrylate （PMMA） domains were dominated in the LC domains. However, when the molar ratio of MMA was increased to 50% （ MMA： DPPC = 1 ： 1 ）, the percentage of the polymer PMMA increased in the LC domains. It is due to phase segregation in mixed LB films of DPPC, MMA and its polymer PMMA at different MMA ratio and deposited surface pressure. Such round-shaped defects in the mixed LB films of MMA/DPPC could induce round-shaped patterns of calcium oxalate monohydrate crystals.

关 键 词：LB膜 缺陷 AFM DPPC MMA 

分 类 号：O484[理学—固体物理]