Su Yan, Wang Zaoming, Legrand Alexandre, Aoyama Takuma, Ma Nattapol, Wang Weitao, Otake Ken-Ichi, Urayama Kenji, Horike Satoshi, Kitagawa Susumu, Furukawa Shuhei, Gu Cheng
State Key Laboratory of Luminescent Materials and Devices, Institute of Polymer Optoelectronic Materials and Devices, South China University of Technology, No. 381 Wushan Road, Tianhe District, Guangzhou 510640, P. R. China.
Institute for Integrated Cell-Material Sciences, Kyoto University, Yoshida, Sakyo-ku, Kyoto 606-8501, Japan.
J Am Chem Soc. 2022 Apr 20;144(15):6861-6870. doi: 10.1021/jacs.2c01090. Epub 2022 Mar 22.
Hypercrosslinked polymers (HCPs), amorphous microporous three-dimensional networks based on covalent linkage of organic building blocks, are a promising class of materials due to their high surface area and easy functionalization; however, this type of material lacks processability due to its network rigidity based on covalent crosslinking. Indeed, the development of strategies to improve its solution processability for broader applications remains challenging. Although HCPs have similar three-dimensionally crosslinked networks to polymer gels, HCPs usually do not form gels but insoluble powders. Herein, we report the synthesis of HCP gels from a thermally induced polymerization of a tetrahedral monomer, which undergoes consecutive solubilization, covalent bond formation, colloidal formation, followed by their aggregation and percolation to yield a hierarchically porous network. The resulting gels feature concentration-dependent hierarchical porosities and mechanical stiffness. Furthermore, these HCP gels can be used as a platform to achieve molecular-level hybridization with a two-dimensional polymer during the HCP gel formation. This method provides functional gels and corresponding aerogels with the enhancement of porosities and mechanical stiffness. Used in column- and membrane-based molecular separation systems, the hybrid gels exhibited a separation of water contaminants with the efficiency of 97.9 and 98.6% for methylene blue and KMnO, respectively. This result demonstrated the potentials of the HCP gels and their hybrid derivatives in separation systems requiring macroscopic scaffolds with hierarchical porosity.
超交联聚合物（HCPs）是基于有机结构单元共价连接的无定形微孔三维网络，由于其高比表面积和易于功能化，是一类很有前途的材料；然而，这类材料由于基于共价交联的网络刚性而缺乏可加工性。事实上，开发提高其溶液可加工性以实现更广泛应用的策略仍然具有挑战性。尽管HCPs具有与聚合物凝胶相似的三维交联网络，但HCPs通常不会形成凝胶，而是形成不溶性粉末。在此，我们报道了通过四面体单体的热诱导聚合合成HCP凝胶，该单体经历连续的溶解、共价键形成、胶体形成，随后聚集和渗滤，从而产生分级多孔网络。所得凝胶具有浓度依赖性的分级孔隙率和机械刚度。此外，这些HCP凝胶可作为一个平台，在HCP凝胶形成过程中实现与二维聚合物的分子水平杂交。该方法提供了具有增强孔隙率和机械刚度的功能性凝胶及相应的气凝胶。用于基于柱和膜的分子分离系统时，混合凝胶对亚甲基蓝和高锰酸钾的水污染物分离效率分别为97.9%和98.6%。这一结果证明了HCP凝胶及其杂化衍生物在需要具有分级孔隙率的宏观支架的分离系统中的潜力。
