Morphologies and bridging properties of graft copolymers.
Morphologies and bridging properties of graft copolymers.
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DOI：
10.1021/jp0650432
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发表时间：
2007-01
期刊：
影响因子：
--
通讯作者：
Liangshun Zhang;Jiaping Lin;Shaoliang Lin
中科院分区：
文献类型：
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作者：
Liangshun Zhang;Jiaping Lin;Shaoliang Lin
用二维自洽场实空间算法研究了本体接枝共聚物的形态结构和桥联性质。通过改变接枝点的位置和枝晶数目，可以实现从柱状相到层状相的相变。桥联构象的分数f（bridge）显示出随着自由端嵌段的长度tau1和分支的数目m的增加而减小的趋势。当柱状相转变为层状相时，f（桥）值有一个不连续的下降。还研究了m与单位面积桥连链数nb之间的关系，该关系与共聚物的机械性能有关。结果发现，在圆柱相中，Nb随着m的增加而增加。然而，在层状相中，当m增加时，nb减少。提出了接枝点位置和分支数是材料设计的两个重要参数。
Morphologies and bridging properties of graft copolymers in the bulk state were studied by using a real-space algorithm of self-consistent field theory in two dimensions. The phase transition from cylindrical to lamellar phase can be triggered by changing the position of graft points and the number of branches. The fraction of bridged conformation, f(bridge), shows a tendency to decrease with increasing the length of free end blocks, tau1, and the number of branches, m. The value of f(bridge) has a discontinuous drop when the transition from cylindrical to lamellar phase takes place. The relationship between m and the number of bridged chains per unit area, nb, which is associated with the mechanical properties of copolymers, was also examined. It was found that nb increases with increasing m in the cylindrical phase. However, in the lamellar phase, nb decreases when m increases. It is proposed that the position of graft points and the number of branches are two important parameters for material design.