Dupuis Romain, Barboiu Mihail, Maurin Guillaume
Institut Européen des Membranes, Adaptive Supramolecular Nanosystems Group, University of Montpellier, ENSCM-CNRS UMR5635, Place E. Bataillon CC047 34095 Montpellier France
ICGM, Univ. Montpellier, CNRS, ENSCM 34095 Montpellier France
Chem Sci. 2022 Apr 13;13(18):5141-5147. doi: 10.1039/d2sc01355j. eCollection 2022 May 11.
Rubbery organic frameworks-ROFs have recently emerged as an intriguing class of dynamers by virtue of reversible connections between their building units. Their highly adaptative features at the origin of their spectacular self-healing properties made them also attractive candidates for the development of gas-selective membranes combining high selectivity and fast permeability. So far, little is known on the origin of this unique trait and this clearly hampers the exploitation of this class of dynamers in many areas where stimuli-responsive pore dynamics is of great importance. To address this lack of fundamental knowledge, herein we unravel the self-assembly process of ROFs the development of an advanced computational methodology combining quantum and force field molecular simulations that enable the description of reversible connections of building units and the long-range organization of the cross-linked ROF network. We demonstrate that both accurate energy barriers associated with the covalent bond formation between the building units and presence of solvent are key parameters to ensure the construction of reliable ROF structure models that are supported by a set of experimental data collected on synthesized ROFs including density, connectivity and porosity. Atomistic insights into the unusual guest-responsive pore dynamics of this intriguing class of dynamers are further gained with a special attention paid to the tunability of this pore flexibility by controlling the chemical composition of the building units. As a further stage, the dynamics of CO in these compliance frameworks is scrutinized to shed light on the mechanism at the origin of their promising performance as CO-selective membranes. We highlight that guest-triggered pore dynamics enables the creation of a diffusion pathway to ensure effective gas transport throughout the whole ROF. This knowledge of the pore structure and its guest-responsive dynamics at the microscopic level is unprecedented in the field of dynamers and it is expected to pave the way towards the optimization of this class of adaptive porous frameworks for many potential applications. Interestingly, this computational approach can be transferable to the exploration of any complex disordered systems showing a high degree of flexibility and guest induced structure/pore reorganization.
橡胶状有机框架（ROFs）最近凭借其构建单元之间的可逆连接，成为一类引人关注的动态聚合物。它们高度适应性的特性是其惊人的自愈性能的根源，这也使它们成为开发兼具高选择性和快速渗透性的气体选择性膜的有吸引力的候选材料。到目前为止，对于这一独特特性的起源知之甚少，这显然阻碍了这类动态聚合物在许多刺激响应性孔道动力学至关重要的领域的应用。为了解决这一基础知识的不足，在此我们揭示了ROFs的自组装过程，即开发一种先进的计算方法，该方法结合了量子和力场分子模拟，能够描述构建单元的可逆连接以及交联ROF网络的长程组织。我们证明，与构建单元之间共价键形成相关的精确能垒以及溶剂的存在都是确保构建可靠的ROF结构模型的关键参数，这些模型得到了在合成ROF上收集的一组实验数据的支持，包括密度、连接性和孔隙率。通过特别关注通过控制构建单元的化学成分来调节这种孔道灵活性，进一步获得了对这类有趣的动态聚合物异常的客体响应性孔道动力学的原子层面见解。作为进一步的阶段，对这些顺应性框架中CO的动力学进行了仔细研究，以阐明其作为CO选择性膜具有良好性能的起源机制。我们强调客体触发的孔道动力学能够创建一条扩散途径，以确保整个ROF中有效的气体传输。这种在微观层面上对孔道结构及其客体响应性动力学的认识在动态聚合物领域是前所未有的，预计将为优化这类适应性多孔框架以用于许多潜在应用铺平道路。有趣的是，这种计算方法可以转移到探索任何显示出高度灵活性以及客体诱导结构/孔道重组的复杂无序系统。
