Self-recovering stimuli-responsive macrocycle-equipped supramolecular ionogels with unusual mechanical properties

Abstract

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.

Effects of polyethylene spacer length in polymeric electrolytes on gelation of ionic liquids and ionogel properties

“…S7). The elastic moduli of ionogels based on tetramethylene spacers are lower than those of other polymers, but are still comparable to the conventional physical ionogels …”

PVDF based ionogels: applications towards electrochemical devices and membrane separation processes

“…The mechanical properties of ionogels are highly significant for their use in various applications. However, the incorporation of ionic liquids in different solid support materials affects their mechanical properties [58] . Lopez-Barron et al.…”

Logic‐Gate Functions in Chemomechanical Materials

“…Many processes in nature rely on the transformation of chemical stimuli into mechanical movements and shape changes. Biomimetic smart materials open the way for many applications, including actuators, sensors, artificial muscles, drug delivery, self‐healing materials, and tissue engineering …”

“…Biomimetic smart materials open the way for many applications,i ncluding actuators, sensors, artificial muscles, drugd elivery, self-healing materials, and tissue engineering. [12][13][14][15][16] The focus of the present minireview is on chemomechanical polymers, which by molecular recognition exhibit selective swellingo rs hrinking under the influence of external effector compounds. [17] For example, ah ybrid chemomechanical system can consist of ap H-responsive hydrogel attachedt o flexible polymer structures that transform the external signal into micro-or macroscopic movements.…”