Lazutin A A, Govorun E N, Vasilevskaya V V, Khokhlov A R
A. N. Nesmeyanov Institute of Organoelement Compounds RAS, Vavilova ul. 28, Moscow 119991, Russia.
Faculty of Physics, M. V. Lomonosov Moscow State University, Leninskie Gory, Moscow 119991, Russia.
J Chem Phys. 2015 May 14;142(18):184904. doi: 10.1063/1.4920973.
It was found first that macromolecules made of amphiphilic monomer units could form spontaneously an ultra-thin layer on the surface which the macromolecules are grafted to. The width of such layer is about double size of monomer unit consisting of hydrophilic A (repulsive) and hydrophobic (attractive) B beads. The hydrophilic A beads are connected in a polymer chain while hydrophobic B beads are attached to A beads of the backbone as side groups. Three characteristic regimes are distinguished. At low grafting density, the macromolecules form ultra-thin micelles of the shape changing with decrease of distance d between grafting points as following: circular micelles-prolonged micelles-inverse micelles-homogeneous bilayer. Those micelles have approximately constant height and specific top-down A-BB-A structure. At higher grafting density, the micelles start to appear above the single bilayer of amphiphilic macromolecules. The thickness of grafted layer in these cases is different in different regions of grafting surface. Only at rather high density of grafting, the height of macromolecular layer becomes uniform over the whole grafting surface. The study was performed by computer modeling experiments and confirmed in framework of analytical theory.
首先发现，由两亲性单体单元构成的大分子能够在其接枝的表面上自发形成超薄层。该层的宽度约为亲水性A（排斥性）和疏水性（吸引性）B珠子组成的单体单元大小的两倍。亲水性A珠子连接在聚合物链中，而疏水性B珠子作为侧基连接到主链的A珠子上。区分出三种特征状态。在低接枝密度下，大分子形成超薄胶束，其形状随着接枝点之间距离d的减小而变化，如下所示：圆形胶束 - 拉长的胶束 - 反胶束 - 均匀双层。这些胶束具有大致恒定的高度和特定的自上而下的A - BB - A结构。在较高接枝密度下，胶束开始出现在两亲性大分子的单双层之上。在这些情况下，接枝层的厚度在接枝表面的不同区域有所不同。只有在相当高的接枝密度下，大分子层的高度在整个接枝表面上才会变得均匀。该研究通过计算机模拟实验进行，并在分析理论框架内得到证实。
