SAMS research group, University of Strasbourg, Institut Charles Sadron, CNRS, 23 rue du Loess, BP 84047, 67034 Cedex 2 Strasbourg, France.
Matière et Systèmes Complexes (MSC) Laboratory, UMR CNRS 7057, Sorbonne Paris Cité, University of Paris Diderot-Paris VII , Bâtiment Condorcet, 75205 Cedex 13 Paris, France.
J Am Chem Soc. 2017 Apr 5;139(13):4923-4928. doi: 10.1021/jacs.7b00983. Epub 2017 Mar 23.
The implementation of artificial molecular machines in polymer science is an important objective that challenges chemists and physicists in order to access an entirely new class of smart materials. To design such systems, the amplification of a mechanical actuation from the nanoscale up to a macroscopic response in the bulk material is a central issue. In this article we show that bistable [c2]daisy chain rotaxanes (i.e., molecular muscles) can be linked into main-chain Upy-based supramolecular polymers. We then reveal by an in depth quantitative study that the pH actuation of the mechanically active rotaxane at the nanoscale influences the physical reticulation of the polymer chains by changing the supramolecular behavior of the Upy units. This nanoactuation within the local structure of the main chain polymer results in a mechanically controlled sol-gel transition at the macroscopic level.
在聚合物科学中实现人工分子机器是化学家与物理学家面临的一项重要挑战，其目的是获得全新类别的智能材料。为了设计这类系统，需将纳米级机械致动放大到块状材料中的宏观响应，这是一个核心问题。在本文中，我们展示了双稳态 [c2] 雏菊链轮烷（即分子肌肉）可以连接成基于 Upy 的主链超分子聚合物。然后，通过深入的定量研究揭示，机械活性轮烷在纳米尺度上的 pH 致动通过改变 Upy 单元的超分子行为来影响聚合物链的物理交联。这种主链聚合物局部结构内的纳米致动导致在宏观水平上的机械控制溶胶-凝胶转变。
