Surface segregation of highly branched polymer additives in linear hosts
Surface segregation of highly branched polymer additives in linear hosts
复制标题
DOI：
10.1002/polb.21512
复制
发表时间：
2008-09-01
影响因子：
--
通讯作者：
Archer, Lynden A.
中科院分区：
文献类型：
--
作者：
Qian, Zhenyu;Minnikanti, Venkatachala S.;Archer, Lynden A.
用自洽(SCF)平均场格子模拟方法研究了不同支化和超支化聚合物添加剂在化学相似的线性聚合物主体中的熵驱动偏析。模拟结果考虑了分子构型对共混物局部构型熵的影响，但忽略了构型对局部密度和共混物可压缩性的影响。星形、树枝状和梳状添加剂都被发现在化学上相同的线性主体聚合物的表面上富含。其表面过剩的大小随链端数的增加而增加，随分支点附近链段拥挤程度的增加而减小。在支化添加剂的臂数和分子质量保持不变的情况下，我们发现最简单的支化结构对称星形结构对二元聚合物共混物的表面表现出最强烈的偏好。我们表明，一个单一的变量，这里称为“熵驱动力密度”，控制相对表面亲和力的支化添加剂拥有广泛的结构范围。(C)2008年威利期刊公司。
Entropy-driven segregation of various branched and hyperbranched polymeric additives in chemically similar linear polymer hosts is studied using self-consistent (SCF) mean-field lattice simulations. The simulations account for the effect of molecular architecture on local configurational entropy in the blends, but ignores the effect of architecture on local density and blend compressibility. Star, dendrimer, and comb-like additives are all found to be enriched at the surface of chemically identical linear host polymers. The magnitude of their surface excess increases with increased number of chain ends and decreases with increased segmental crowding near the branch point. Provided the number of arms and molecular weight of the branched additives are maintained constant, we find that the simplest branched architecture, the symmetric star, exhibits the strongest preference for the surface of binary polymer blends. We show that a single variable, here termed the "entropic driving force density," controls the relative surface affinities of branched additives possessing a wide range of architectures. (C) 2008 Wiley Periodicals, Inc.