Morphologies of charged diblock copolymers simulated with a neutral coarse-grained model.
Morphologies of charged diblock copolymers simulated with a neutral coarse-grained model.
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DOI：
10.1021/jp201085c
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发表时间：
2011-04-28
影响因子：
3.3
通讯作者：
Moore, Preston B.
中科院分区：
文献类型：
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作者：
Pantano, Diego A.;Klein, Michael L.;Discher, Dennis E.;Moore, Preston B.
我们提出了粗粒度的分子动力学模拟的结果，使用一个不带电的模型，能够捕捉带电的二嵌段共聚物的形态相图的不同区域。具体地说，我们能够再现许多阶段的聚（丙烯酸）-（1，4）-聚丁二烯（PAA-PBA）二嵌段共聚物，Ca+2和水系统的pH值和钙浓度的函数与短程LJ型电位。观察到的形态范围从双层到圆柱体到球形胶束。这样的聚阴离子/阳离子两亲物在水中通常提出了分子模拟的多重挑战，特别是由于许多电荷相互作用，这是长范围的和计算成本高。此外，正是这些相互作用被认为是调节感兴趣的大的两亲物组装体，如脂筏。然而，我们的模型是能够再现不同的形态，由于pH值和有或没有添加的Ca 2+以及横向相分离和域注册中观察到的中性和带电的二嵌段共聚物的混合物。结果表明，电荷的整体效应是一个局部的结构重排，重正化的头基之间的空间排斥。这个简单的模型，这是没有电荷是能够重现复杂的相图，并可用于调查集体现象，在这些带电系统，如域的形成和登记或共定位的脂筏跨双层小叶。
We present the results of coarse grained molecular dynamics simulation using a charge free model that is able to capture different regions of the morphological phase diagram of charged diblock copolymers. Specifically, we were able to reproduce many phases of the poly(acrylic acid)-(1,4)-poly-butadiene (PAA-PBA) diblock copolymer, Ca+2 and water systems as a function of pH and calcium concentration with short range LJ type potentials. The morphologies observed range from bilayers to cylinders to spherical micelles. Such polyanionic/cationic amphiphiles in water typically present multiple challenges for molecular simulations, particularly due to the many charge interactions which are long ranged and computationally costly. Further, it is precisely these interactions that are thought to modulate large amphiphile assemblies of interest such as lipid rafts. However, our model is able to reproduce different morphologies due to pH and with or without the addition of Ca2+ as well as the lateral phase segregation and the domain registration observed in neutral and charged diblock copolymer mixtures. The results suggest that the overall effect of charges is a local structural rearrangement that renormalizes the steric repulsion between the headgroups. This simple model which is devoid of charges is able to reproduce the complex phase diagram and can be used to investigate collective phenomena in these charged systems such as domain formation and registration or co-localization of lipid rafts across bilayer leaflets.
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影响因子：
5.5
作者：
DOUZINAS, KC;COHEN, RE
通讯作者：
COHEN, RE
影响因子：
6
作者：
MANDEL, M
通讯作者：
MANDEL, M
影响因子：
3.3
作者：
Geng, Y;Ahmed, F;Discher, DE
通讯作者：
Discher, DE
影响因子：
3.4
作者：
Schram, V;Thompson, TE
通讯作者：
Thompson, TE
影响因子：
41.2
作者：
通讯作者：
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