Response behavior of diblock copolymer brushes in explicit solvent.
Response behavior of diblock copolymer brushes in explicit solvent.
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DOI：
10.1063/1.4757860
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发表时间：
2012-10
期刊：
影响因子：
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通讯作者：
Kai Gong;B. Marshall;Walter G Chapman
中科院分区：
文献类型：
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作者：
Kai Gong;B. Marshall;Walter G Chapman
了解共聚物刷的相行为对于智能材料的设计具有重要意义。在本文中，我们进行了经典的密度泛函理论计算，研究了两嵌段共聚物刷（A-B）在一个明确的溶剂，其中优先选择A嵌段B嵌段。随着B-嵌段长度（N（B））的增加，我们发现从混合到塌陷，部分暴露，暴露的结构，这是定性与实验一致的共聚物刷的结构转变。相变归因于折叠共聚物刷的熵成本和不同组分之间接触的摩擦效应之间的相互作用。此外，我们还考察了不同参数，如接枝密度（ρ（g）），底部嵌段长度（N（A））和溶剂链长（N（S））对共聚物刷的溶剂响应的影响。过渡链长（N（B））随着ρ（g）和N（A）的减小而增加，并且较小的溶剂分子由于其较低的渗透成本而使塌陷结构较不稳定。我们的研究结果提供了洞察共聚物刷在选择性溶剂中的相行为从分子的角度。
The understanding of phase behavior of copolymer brushes is of fundamental importance for the design of smart materials. In this paper, we have performed classical density functional theory calculations to study diblock copolymer brushes (A-B) in an explicit solvent which prefers the A block to B block. With increasing B-block length (N(B)), we find a structural transition of the copolymer brush from mixed to collapsed, partial-exposed, and exposed structure, which is qualitatively consistent with experiments. The phase transitions are attributed to the interplay between entropic cost of folding copolymer brushes and enthalpic effect of contact between unlike components. In addition, we examine the effect of different parameters, such as grafting density (ρ(g)), the bottom block length (N(A)), and the chain length of solvent (N(S)) on the solvent response of copolymer brushes. The transition chain length (N(B)) increases with decreasing ρ(g) and N(A), and a smaller solvent molecule makes the collapsed structure less stable due to its lower penetration cost. Our results provide the insight to phase behavior of copolymer brushes in selective solvents from a molecular view.