2022-06-08 ワシントン大学セントルイス
合成方法の合理化と効率化を図った後、カテナン系架橋剤を材料を構成するネットワークに組み込んで、材料の剛性、弾性、力の散逸特性を調整することを目指した。カテナンは、2つ以上の環からなる機械的に結合した分子であり、カテナンを組み込んだ材料は、外力を受けたときに回転、伸張、圧縮などの動きをするのに十分な自由度がある。
バーンズとノシグリアは、カテナンに金属を添加（メタル化）することで、環を特定の形に固定し、ゲル素材全体をより硬く、より弾力的にすることができることを発見した。
＜関連情報＞
- https://chemistry.wustl.edu/news/interlocking-rings-unlock-new-material-properties
- https://pubs.acs.org/doi/10.1021/jacs.2c03166
カテナン架橋ゲルの機械的特性を調整するポストゲル化戦略としてのメタレーション/脱メタル化 Metalation/Demetalation as a Postgelation Strategy To Tune the Mechanical Properties of Catenane-Crosslinked Gels
Mark A. Nosiglia,athan D. Colley, Mary K. Danielson, Mark S. Palmquist, Abigail O. Delawder, Sheila L. Tran, Gray H. Harlan, and Jonathan C. Barnes
Journal of the American Chemical Society Published:May 26, 2022
DOI:https://doi.org/10.1021/jacs.2c03166
Abstract
Mechanically interlocked molecules (MIMs) possess unique architectures and nontraditional degrees of freedom that arise from well-defined topologies that are achieved through precise mechanical bonding. Incorporation of MIMs into materials can thus provide an avenue to discover new and emergent macroscale properties. Here, the synthesis of a phenanthroline-based [2]catenane crosslinker and its incorporation into polyacrylate organogels are described. Specifically, Cu(I) metalation and demetalation was used as a postgelation strategy to tune the mechanical properties of a gel by controlling the conformational motions of integrated MIMs. The organogels were prepared via thermally initiated free radical polymerization, and Cu(I) metal was added in MeOH to the pretreated, swollen gels. Demetalation of the gels was achieved by adding lithium cyanide and washing the gels. Changes in Young’s and shear moduli, as well as tensile strength, were quantified through oscillatory shear rheology and tensile testing. The reported approach provides a general method for postgelation tuning of mechanical properties using metals and well-defined catenane topologies as part of a gel network architecture.
