The self-assembly of linear polymers containing chiral IL units generates a high-order supramacromolecular structure with a complex hierarchical architecture, which is able to exhibit thermoresponsive behavior (lower critical solution temperature: LCST) with different structural elements that can be used to fine tune this LCST.Ionic liquids (ILs) encompass a variety of compounds and materials with great potential for applications ranging from new chemical technologies to use in industrial processes. Their physicochemical properties depend on the interactions established between the participating cations and anions that can determine variations in the self-assembled structure. Indeed, ILs have been described as ''polymeric supramolecular fluids'' and, consequently, as systems highly structured in the liquid state. 1 Interestingly, polymers having functionalities similar to those of ILs (polymeric ionic liquids: PILs) have been pursued for developing new advanced materials, which can provide all beneficial properties of ILs without their associated drawbacks. 2 Thus, the preparation of functional nanostructured materials or composites based on ILs represents an exciting and significant area of opportunity for developing multifunctional, hierarchically structured materials. 3 As for ILs, one important advantage of PILs is their potential for displaying a large level of chemical and structural diversity and, hence, physico-chemical characteristics. 4 Among them, chirality can be considered one of the most interesting characteristics, 5 and we have reported a simple and robust modular synthetic strategy that leads to a large variety of configurationally and structurally diverse chiral ionic liquids (CILs). 6,7 The in-depth study of these CILs has allowed us to analyse in detail the structure-property relationship for these compounds. 6 Here, we report the synthesis and LCST-type phase transition based on a new class of chiral-polymeric ionic liquids (CPILs). The poly(VBC)-2 was obtained with a 56% polymerization yield, a molecular weight of 18.9 kg mol À1 and a polydispersity of 1.5. 8 The corresponding CPILs-4a-c were prepared by substitution of the chloride groups by different chiral imidazoles (CILs-3a-c) derived from several amino acids with variable N-amide substitution (Scheme 1 and ESI †). 6 To our surprise, and as observed by the naked eye, the solution of CPIL-4a in chloroform became turbid when the temperature was increased, as shown in Fig. 1. 9 This phenomenon is reversible when the stimulus is reversed and the poly-CPIL-4a re-dissolved upon cooling. This phenomenon is known as a lower critical solution temperature (LCST)-type phase transition. Although LCST-type behaviour has already been observed for poly-(N-isopropylacrylamide)-PIL copolymers and PIL homopolymers, 10 such a behaviour had never been observed for CPILs. In view of this observation, a solution containing 1.0 mg mL À1 of CPIL-4a in CHCl 3 was analysed at different temperatures by UV-Vis spectroscopy and circular dichroism (CD). The tempe...
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
customersupport@researchsolutions.com
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.