【作者】 王玲；

【导师】 杨恺；

【作者基本信息】 苏州大学 ， 材料物理与化学， 2014， 硕士

【摘要】 双亲性嵌段共聚物在水溶液中能够自发地组装成各种微结构，如平面双层膜、胶束等。这些结构在生物医药方面有着极其重要的应用。尤其是双亲性嵌段共聚物形成的平面双层膜既可以作为生物膜的一个简单模型，帮助人们探索细胞膜的生物功能。共聚物胶束因其有良好的稳定性而被广泛地应用于药物输运等。本文主要采用分子动力学（MD）方法研究了双亲嵌段共聚物膜与刚/柔性纳米颗粒的相互作用机制。其中，共聚物胶束由于其可形变性，因此可被看成是柔性的纳米颗粒，而无机纳米粒子等则可定义为刚性纳米颗粒。首先，我们研究了柔性纳米颗粒—共聚物胶束与双亲性嵌段共聚物膜的融合过程。我们发现胶束与共聚物膜之间的距离、组成胶束的聚合物的数目等因素会强烈影响两者的融合。当组成胶束的数目较少时，两者之间的距离强烈地影响膜与胶束的融合：当胶束离膜很近时，两者不会发生作用。而适当增加胶束与膜的距离时，胶束才会与膜发生融合现象。但随着胶束中PEG链的数目增加，两者的相互作用情况会随之发生变化。此时，距离将不再是影响其融合的主要因素。在我们调查的距离范围内，胶束都会与膜发生融合。如果进一步增加PEG连的数目，我们发现两者之间距离的影响又会发生变化。在这种情况下，只有胶束距离膜较近时，胶束才会与膜发生融合现象。其次，我们研究了刚性纳米颗粒—超细型纳米颗粒与双亲嵌段共聚物膜的吸附过程。通过使用分子动力学模拟，我们发现超细型纳米颗粒的大小和形状都会影响纳米颗粒与共聚物膜的相互作用，使得两者处于附着、分离以及颗粒被膜中的聚合物链缠绕等状态。特别是随着纳米颗粒体积的减小，纳米颗粒的形状对吸附的影响反而会变得更加重要。我们的研究表明，共聚物膜与颗粒之间的亲和性与膜中聚合物链由于受到颗粒的相互作用而产生的链段的形变之间的竞争关系是决定两者最终相互作用状态的关键因素。更多还原

【Abstract】 Amphiphilic block copolymers can spontaneously assemble into a variety ofnanostructures in aqueous solution, such as planar bilayers and micelles, etc. Suchnanostructures are significant for many biomedical applications. In this thesis, we studiedthe interactions between some type of rigid/soft nanoparticles and a bilayer membranecomposed of amphiphilic copolymers with molecular dynamics (MD). Herein, the micelles,due to the ability of shape deformation, are viewed as soft nanoparticles in the simulations,while the inorganic nanoparticles are considered as rigid ones.First, the fusion between an amphiphilic copolymer micelle and an amphiphiliccopolymer bilayer membrane is investigated. It is found that the fusion between the micelleand the membrane is influenced by the distance between them as well as the amount ofcopolymer molecules those composing the micelle. When the micelle is small (i.e., theamount of copolymers composing the micelle is low), the factor of distance plays animportant role in governing the fusion between the micelle and the membrane. If they areclose enough, even no fusion occurs; however, with the increase of the distance, themicelle possibly becomes merging into the membrane. When the micelle is bigger, theinfluence of the initial distance weakens. However, when the size of the micelle is furtherincreased, fusion events are only observed when the micelle is close to the membrane.Then, the adhesion of an ultrasmall rigid nanoparticle on an amphiphilic copolymerbilayer membrane is investigated. By using molecular dynamics, we find that both size andshape of an ultrasmall nanoparticle strongly affect its adhesion states on a bilayermembrane (e.g., adhesion, separation or entwined by polymer chains). Interestingly, our simulations show that with the decrease of particle size, the effect of particle shapebecomes even more evident for the adhesion behavior. It is indicated that the competitionbetween nanoparticle-polymer binding and polymer chain deformation, both of which areinfluenced by particle size and shape, determines the final adhesion states of an ultrasmallnanoparticle.更多还原