Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195 Berlin, Germany.
Org Biomol Chem. 2014 Jan 21;12(3):503-10. doi: 10.1039/c3ob41523f. Epub 2013 Nov 27.
A chiral, crown-ether-functionalized bisurea gelator forms supramolecular gels in ionic liquids. The resulting ionogels show a remarkably high thermal stability with gel-sol transition temperatures (T(gs)) reaching more than 100 °C. The mechanical strength of these ionogels is surprisingly high and even comparable to that of cross-linked protein fibres. Furthermore, the ionogels exhibit rapid self-recovery properties after structural damage caused by deformation. Pseudorotaxanes form from the gelators' benzo[21]crown-7 ethers as the wheels and secondary ammonium ions as the axles despite the competition between that cation and the imidazolium ions of the ionic liquid for crown ether binding. Pseudorotaxane formation as an external chemical stimulus triggers the gel-sol transition of the ionogels.
一种手性冠醚功能化双脲凝胶剂在离子液体中形成超分子凝胶。所得离子凝胶具有非常高的热稳定性，凝胶-溶胶转变温度（T(gs)）超过 100°C。这些离子凝胶的机械强度出人意料地高，甚至可与交联的蛋白质纤维相媲美。此外，离子凝胶在由变形引起的结构损坏后表现出快速的自恢复特性。尽管阳离子与离子液体的咪唑鎓离子竞争冠醚结合，但凝胶剂的苯并[21]冠-7 醚作为轮，仲铵离子作为轴形成伪轮烷。作为外部化学刺激的伪轮烷形成触发离子凝胶的凝胶-溶胶转变。
