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采用耗散粒子动力学(DPD)方法研究了嵌段共聚物在纳米微滴中的相分离行为.模拟是将共聚物纳米微滴置于溶剂环境中进行自发相分离,从而形成一些图案化结构.由于是受限体系,所形成的结构和在溶液或熔融体中形成的相分离结构有所差异,这些结构的形成与亲/疏溶剂嵌段比例(RH/T)有关系.随着亲/疏溶剂嵌段比例的增加,依次形成了枣糕球体、排球状相、多层囊泡(洋葱相)、笼状相、纳米杆状相和分散胶束等结构.我们对洋葱相的形成过程进行了详细的描述.溶剂粒子的集群属性有助于更加深入地了解洋葱相的结构衍化.采用密度曲线分析了洋葱相的结构.在较高的亲/疏溶剂嵌段的比例条件下,嵌段共聚物主要表现为亲溶剂性,通过吸收大量的溶剂溶胀形成疏松结构或瓦解形成分散的胶束悬浮在溶剂中.本文模拟结果与理论或实验结果基本吻合.
The phase separation behavior of block copolymers in nanodroplets was studied by dissipative particle dynamics (DPD) method. The simulation was to separate the copolymer nanodroplets into a solvent environment to form spontaneous phase separation and to form some patterned structures Due to the limited system, the structures formed differ from the phase separation structures formed in the solution or melt and the formation of these structures is related to the ratio of hydrophilic / solvophobic blocks (RH / T) / Solvate block ratio, which in turn led to the formation of the jujube cake sphere, volleyball phase, multilamellar vesicles (onion phase), cage phase, nano-rod phase and dispersed micelles.We formed the onion phase The process is described in detail.The clustering properties of solvent particles help to understand the structure evolution of onion phase more.Using density curve to analyze the structure of onion phase.Under the condition of higher proportion of pro / The block copolymer is mainly characterized by its solvent-solubility, which is absorbed by a large amount of solvent and swollen to form loose structure or disintegrated to form dispersed micelles suspended in the solvent.The simulation results in this paper are in good agreement with the theoretical or experimental results.