Lebedeva Inna O, Zhulina Ekaterina B, Leermakers Frans A M, Borisov Oleg V
Institut des Sciences Analytiques et de Physico-Chimie pour l'Environnement et les Matériaux, UMR 5254 CNRS UPPA, Pau, France.
The Peter the Great St.Petersburg Polytechnic University , 195251, St. Petersburg, Russia.
Langmuir. 2017 Feb 7;33(5):1315-1325. doi: 10.1021/acs.langmuir.6b04285. Epub 2017 Jan 30.
We present a theory of conformational transition triggered by inferior solvent strength in brushes formed by dendritically branched macromolecules tethered to planar, concave, or convex cylindrical and spherical surfaces. In the regime of linear elasticity for brush-forming dendrons, an analytical strong stretching self-consistent field (SS-SCF) approach provides brush conformational properties as a function of solvent strength. A boxlike model is applied to describe the collapse transition in brushes formed by macromolecules with arbitrary treelike topology, including hyperbranched polymers. We demonstrate that an increase in the degree of branching, that is, an increase in the number of generations or/and functionality of branching points in tethered macromolecules, makes the swelling-to-collapse transition less sharp. A decrease in surface curvature has a similar effect. The numerical Scheutjens-Fleer self-consistent field approach is used to analyze the collapse transition in dendron brushes in the nonlinear stretching regime. It is demonstrated that inferior solvent strength suppresses stratification that is exhibited under good solvent conditions by densely grafted dendron brushes.
我们提出了一种关于构象转变的理论,该转变由附着在平面、凹面或凸面圆柱和球形表面上的树枝状支化大分子形成的刷状物中较差的溶剂强度引发。在形成刷状物的树枝状分子的线性弹性范围内,一种解析的强拉伸自洽场(SS-SCF)方法给出了刷状物的构象性质作为溶剂强度的函数。一个盒状模型被用于描述由具有任意树状拓扑结构的大分子形成的刷状物中的塌缩转变,包括超支化聚合物。我们证明,支化度的增加,即附着的大分子中分支点的代数或/和官能度的增加,会使溶胀到塌缩的转变变得不那么尖锐。表面曲率的减小也有类似的效果。数值Scheutjens-Fleer自洽场方法被用于分析非线性拉伸范围内树枝状分子刷状物中的塌缩转变。结果表明,较差的溶剂强度会抑制在良好溶剂条件下由密集接枝的树枝状分子刷状物所表现出的分层现象。