Controlling the growth and shape of chiral supramolecular polymers in water
Controlling the growth and shape of chiral supramolecular polymers in water
复制标题
DOI：
10.1073/pnas.1009592107
复制
发表时间：
2010-10-19
影响因子：
11.1
通讯作者：
Meijer, E. W.
中科院分区：
文献类型：
--
作者：
Besenius, Pol;Portale, Giuseppe;Meijer, E. W.
在纳米结构功能材料的非共价合成中，一个具有挑战性的目标是形成统一的特征，这些特征表现出明确的性质，例如，精确控制聚集体的形状、大小和稳定性。特别是，对于水基一维超分子聚合物来说，这是一项艰巨的任务。在这里，我们公开了一种基于自组装盘状两亲分子的策略，该策略导致对有序的手性柱状聚集体的堆积长度和形状进行控制。通过平衡聚合构建块疏水核心内吸引的非共价力和亲水边缘上的静电排斥作用，我们成功地从细长的棒状组件切换到小型和离散的对象。有趣的是，这种从棒到球的转变表现为依赖温度的自组装机制中协作性的丧失。用圆二色谱、UV和1H-核磁共振光谱、小角X射线散射和低温电子显微镜对聚集体进行了表征。与生物学中发现的许多系统类似，自组装路径的机械细节强调了协作性的重要性，这是决定所产生的超分子聚合物的物理性质的关键特征。
A challenging target in the noncovalent synthesis of nanostructured functional materials is the formation of uniform features that exhibit well-defined properties, e. g., precise control over the aggregate shape, size, and stability. In particular, for aqueous-based one-dimensional supramolecular polymers, this is a daunting task. Here we disclose a strategy based on self-assembling discotic amphiphiles that leads to the control over stack length and shape of ordered, chiral columnar aggregates. By balancing out attractive noncovalent forces within the hydrophobic core of the polymerizing building blocks with electrostatic repulsive interactions on the hydrophilic rim we managed to switch from elongated, rod-like assemblies to small and discrete objects. Intriguingly this rod-to-sphere transition is expressed in a loss of cooperativity in the temperature-dependent self-assembly mechanism. The aggregates were characterized using circular dichroism, UV and 1H-NMR spectroscopy, small angle X-ray scattering, and cryotransmission electron microscopy. In analogy to many systems found in biology, mechanistic details of the self-assembly pathways emphasize the importance of cooperativity as a key feature that dictates the physical properties of the produced supramolecular polymers.