Mechanism insights in controlling host-guest (de)complexation by thermoresponsive polymer phase transitions

Hui Guo (1, 2) , Gaëlle Le Fer (3) , Thi Nga Tran (1) , Aurélie Malfait (3) , Dominique Hourdet (1) , Alba Marcellan (1) , François Stoffelbach (4) , Joël Lyskawa (3) , Richard Hoogenboom (5) , Patrice Woisel (3)

1 SIMM - Sciences et Ingénierie de la Matière Molle (UMR 7615)
2 SYSU - Sun Yat-sen University [Guangzhou]
3 UMET - Unité Matériaux et Transformations - UMR 8207
4 IPCM - Institut Parisien de Chimie Moléculaire
5 UGENT - Universiteit Gent = Ghent University

The combination of (thermo)responsive polymers with supramolecular chemistry recently allowed the development of adaptative materials based on the reversible regulation of host-guest complexation. The properties of these artificial systems rely on their synthetic design, which requires a perfect understanding of the mechanisms triggering the thermo-induced decomplexation. Despite recent progress, the origins of this phenomenon are still not fully understood. To investigate the effect of phase separation mechanism and thermodynamics on the host-guest (de)complexation behavior, different naphthalene-functionalized (guest) thermoresponsive polymers, including lower critical solution temperature (LCST) and upper critical solution temperature (UCST) polymers, were prepared. The hostguest complexation of the polymers with cyclobis(paraquat-p-phenylene) (Blue Box) was investigated in water at different temperatures. Host-guest complexation was lost upon heating-induced hydrophobic phase separation of complexed guest-functionalized LCST-polymers, while, in contrast, the host-guest complex was retained upon cooling-induced hydrogen bond-driven phase separation of a complexed guest-functionalized UCST polymer. This comparative analysis showed that the mechanism behind the thermoresponsive polymer phase separation is a key factor that dominates the host-guest (de)complexation.

Domaines: Polymères

Hui Guo, Gaëlle Le Fer, Thi Nga Tran, Aurélie Malfait, Dominique Hourdet, et al.. Mechanism insights in controlling host-guest (de)complexation by thermoresponsive polymer phase transitions. Polymer Chemistry, 2022, 13 (25), pp.3742-3749. ⟨10.1039/D2PY00219A⟩. ⟨hal-03790536⟩