LCST‐Type Hyperbranched Poly(oligo(ethylene glycol) with Thermo‐ and CO₂‐Responsive Backbone

Abstract

A novel hyperbranched lower critical solution temperature (LCST) polymer with sharp temperature and CO -responsive behaviors is presented in this study. The target polymer of hyperbranched poly(oligo(ethylene glycol) (HBPOEG) is constructed using POEG as the backbone and tertiary amines as branch points. Phase transition of HBPOEG in aqueous solution is investigated by heating and cooling the system; the results indicate that HBPOEG in aqueous solution has a concentration-dependent phase transition behavior with excellent repeatability. Moreover, LCST of HBPOEG can be tuned by bubbling CO into the solution, as the tertiary amines can be protonated and the solubility of the polymer would increase by bubbling CO into the system, leading to an increase of LCST of the polymer. Further bubbling N to remove CO can reversibly turn back the LCST to its original value. This backbone-based hyperbranched LCST polymer with both CO and temperature responsiveness can be applied in application areas like drug delivery, gene transfection, functional coatings, etc.

Thermoresponsive properties of polyacrylamides in physiological solutions

“…T CP depends on polymer molar mass (dispersity) 1,26-29 and concentration, 1,26,30 on solution pH 9,[31][32][33] and on the concentration and type of ions [33][34][35][36][37][38][39][40][41] (due to the Hofmeister effect 34 ), proteins and other macromolecules 33,[42][43][44][45] in solution (due to the excluded volume/molecular crowding effect, 46 competition for solvent, or non-covalent protein-polymer interactions 47 ), among other factors. 1,27,48 Polymer tacticity 1,49 and terminal moiety (e.g., a chain transfer agent, CTA) 1,50,51 and even fairly subtle environmental changes, including changes in solution pH, 32,40,52 can also affect the T CP . Several theories, especially the lattice fluid theory with hydrogen-bonding corrections (LFT-HB) 53 and other (more advanced) models, 45,[54][55][56][57] reliably describe T CP as a function of polymer concentration, but they are rather complicated and heavily rely on empirical data.…”

Synthesis and Properties of Side-Chain Functionalized Polytetrahydrofuran Derivatives via the Blue-Light Photocatalytic Thiol-Ene Reaction

“…In the past decades, the backbone-thermoresponsive polymers have been extensively studied because of their various promising applications, especially in the synthesis of hyperbranched polymers, which are indeed prepared by combining both hydrophobic and hydrophilic components into the polymer backbone to form a hydrophobic-hydrophilic balance system [37,38,39]. However, up to now, the brush polyether with a backbone-thermoresponsive has not yet been synthesized.…”

Synthesis of Thermo‐, Oxidation‐, pH‐, and CO2‐Responsive Polymers via the Combination of Aza‐Michael and Thiol‐Michael Reactions in One Pot

“…Hence, the obtained polymers are integrated to be triply responsive (thermo‐, oxidation‐, and pH/CO 2 ‐responsive). The behavioral change of a macromolecule in biological system is often a result of a combination of environmental changes, and therefore multistimuli‐responsive polymer, which can provide better spatiotemporal control, offers an ideal platform to mimic the biological processes and has received much attention in the past decade . Owing to the commercially available starting materials, our work provides a convenient strategy for the synthesis of applicable multifunctional polymers in a large scale.…”