The columnar mesophase, in which the molecular or supramolecular building blocks with rod-like geometry pack into two-dimensional (2D) lattices, is an important class of mesomorphic structure having been found in various liquid crystalline materials for practical applications. The cylindrical micelles assembled by amphiphilic surfactants may also form columnar mesophases with the micelle packing symmetry being tunable by the molecular characteristics of the surfactants. In this study, we demonstrate that a positively charged tree-like polymer, poly(amidoamine) (PAMAM) G4 dendrimer, acted as an effective structure-directing agent for the columnar mesophase of a common anionic surfactant, sodium dodecyl sulfate (SDS), via their electrostatic interaction. By adjusting the dendrimer charge density and the nominal binding ratio (X_n) of SDS to dendrimer, the electrostatic complexes self-assembled to form a body-centered cubic (BCC) sphere phase, wherein the dendrimers were staggered between the interspaces of the SDS spherical micelles packed in the BCC lattice. Four types of 2D columnar mesophase composed of SDS cylindrical micelles and dendrimers were accommodated within the interstitial tunnels, including the hexagonal columnar phase (Col_hex), simple rectangular columnar phase (Col_sr), oblique columnar phase (Col_ob) and centered rectangular columnar phase (Col_cr). A detailed analysis of the geometry of the dendrimer in the columnar mesophases revealed that the structural transition was governed by the interplay among the lateral and axial deformations of the dendrimer, and the deformation of the SDS micelle cross section for achieving effective charge matching and accommodation of the dendrimer. The present study demonstrated the power of the dendrimer in directing the long-range ordered packing of oppositely charged cylinders to yield a rich structural polymorphism of the columnar mesophase that may be exploited for the development of functional materials.

中文翻译：

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树状聚合物介导的表面活性剂柱状中间相

柱状中间相是具有重要形状的同构结构，其中具有棒状几何形状的分子或超分子构建体堆积成二维（2D）晶格，在实际应用中已经发现了它们。由两亲性表面活性剂组装的圆柱形胶束也可以形成柱状中间相，其中胶束堆积对称性可以通过表面活性剂的分子特性来调节。在这项研究中，我们证明了带正电荷的树状聚合物聚（酰胺基胺）（PAMAM）G4树状聚合物，可作为常见阴离子表面活性剂十二烷基硫酸钠（SDS）的柱状中间相的有效结构导向剂，通过它们的静电相互作用。通过调整树枝状聚合物的电荷密度和标称结合率（X _Ñ SDS）至树枝状聚合物，静电络合物自组装，以形成体心立方（BCC）相球体，其中所述树枝状聚合物被装在BCC晶格中的SDS球形胶束的间隙之间交错。由SDS圆柱形胶束和树枝状大分子组成的2D柱状中间相包括在间隙隧道中，包括六方柱状相（Col _hex），简单矩形柱状相（Col _sr），斜柱状相（Col _ob）和居中矩形柱状相（COL _CR）。对柱状中间相中的树枝状大分子的几何结构的详细分析表明，结构转变受树枝状大分子的横向和轴向变形以及SDS胶束横截面变形之间的相互作用所控制，以实现有效的电荷匹配和电荷的容纳。树状聚合物。本研究证明了树状大分子在指导带相反电荷的圆柱体的长程有序堆积以产生丰富的柱状中间相结构多态性方面的能力，可用于开发功能材料。