Recognition-Mediated Hydrogel Swelling Controlled by Interaction with a Negative Thermoresponsive LCST Polymer.
Most polymeric thermoresponsive hydrogels contract upon heating beyond the lower critical solution temperature (LCST) of the polymers used. Herein, we report a supramolecular hydrogel system that shows the opposite temperature dependence. When the non-thermosesponsive hydrogel NaphtGel, containing dialkoxynaphthalene guest molecules, becomes complexed with the tetra cationic macrocyclic host CBPQT4+ , swelling occurred as a result of host-guest complex formation leading to charge repulsion between the host units, as well as an osmotic contribution of chloride counter-ions embedded in the network. The immersion of NaphtGel in a solution of poly(N-isopropylacrylamide) with tetrathiafulvalene (TTF) end groups complexed with CBPQT4+ induced positive thermoresponsive behaviour. The LCST-induced dethreading of the polymer-based pseudorotaxane upon heating led to transfer of the CBPQT4+ host and a concomitant swelling of NaphtGel. Subsequent cooling led to reformation of the TTF-based host-guest complexes in solution and contraction of the hydrogel.
['Belal|Khaled|K|', 'Stoffelbach|François|F|', 'Lyskawa|Joël|J|', 'Fumagalli|Matthieu|M|', 'Hourdet|Dominique|D|', 'Marcellan|Alba|A|', 'Smet|Lieselot De|L|', 'de la Rosa|Victor R|VR|', 'Cooke|Graeme|G|', 'Hoogenboom|Richard|R|0000-0001-7398-2058', 'Woisel|Patrice|P|']
hydrogels swelling host-guest compounds supramolecular chemistry thermoresponsive polymers