Triple Thermoresponsiveness of a TADDOL-Based Homopolymer through the Formation of Supramolecular Complexes with Chiral Guest Molecules at Variable Ratios

Abstract

Multi-thermoresponsiveness which exhibits more than triple phase transitions has not been achieved yet. Current research studies have reported double thermoresponsive copolymers having two kinds of polymer chains. However, the molecular design strategy of triple thermoresponsiveness remains unclear. Herein, we report a triple thermoresponsive chiral homopolymer which exhibits UCST− LCST−UCST-type phase transitions. The polymer contains the α,α,α′,α′-tetraaryl-2,2-disubstituted 1,3-dioxolane-4,5-dimethanol moiety in the side chains, where multiple supramolecular complexes between the host polymer and guest molecules are formed. The formations and dynamic changes in the multiple complexes of model compounds were monitored by 1 H NMR spectroscopy. We concluded that the key factor of the triple thermoresponsive behavior is the stoichiometric change in the multiple complexes. This work can extend the molecular design of the thermoresponsive polymer and lead to the next stage of functional polymer materials.

Molecular bases for temperature sensitivity in supramolecular assemblies and their applications as thermoresponsive soft materials

“…13 Some of assemblies can exhibit both LCST and UCST depending on the molecular structure, concentration, and external additives. [14][15][16][17] A variety of molecules have been designed for temperatureresponsive assemblies including dendrimers, 18 random 19 and block 20 copolymers, and small molecules such as lipids. 21 The temperature-responsiveness can be manipulated by several parameters e.g., molecular structure, functional groups, concentration, and hydrophilic-lipophilic balance (HLB).…”

“…Previously, thermoresponsive materials have been summarized in some reviews from different perspectives. Most of them focuses on material components 9,11,22,23 and applications such as delivery, 7,16,24,25 tissue engineering, 26,27 and catalysis. 28 In this review, we focus on the molecular bases and factors behind the temperature-responsiveness.…”

Thermoresponsive polymers in non-aqueous solutions

“…25). 138 The addition of hydrogen bond acceptors or donors, such as camphor, methanol and borneol, resulted in single thermoresponsiveness, while the addition of quinine, containing four hydrogen bonding sites, led to a sol-gel transition due to the bonding of multiple polymer chains, inducing gelation of the polymer. 138…”

“…Fig. 25 Schematic depiction of the synthesis of poly(3-((4R,5R)-4,5-bis(hydroxydiphenylmethyl)-2-methyl-1,3-dioxolane-2-yl)propyl acrylate ( poly (T5)) 138. …”

Thermoresponsiveness of Carboxylated Polyallylamines Induced by Divalent Counterions as Ionic Effectors

“…A novel strategy for providing and regulating thermoresponsiveness to polymer species has been recently developed based on ternary systems by adding effectors to polymer and solvent systems. ,, In the ternary systems, organic molecules that can interact with polymers and regulate their solubility in the solvents are added as effectors, leading to the a posteriori acquisition of thermoresponsiveness for nonthermoresponsive polymers. As a representative, polymers with urea groups at side chains are insoluble in nonpolar organic solvents because of strong intermolecular hydrogen bonding among polymers, whereas the addition of various organic molecules with hydrogen-bonding capability provided a thermoresponsive soluble–insoluble phase transition for the polymers. , In addition, charge transfer complex formation between polymer and effector causing solvation can provide a posteriori acquisition of thermoresponsiveness of polymers. , These effector-induced thermoresponsive polymers occur in organic solvent systems, but they are not limited to organic solvent systems and have also been reported in aqueous systems.…”