Synthesis of Novel pH-Tunable Thermoresponsive Hydroxyl-Terminated Hyperbranched Polyether

Abstract

In this study, a new pH-tunable thermoresponsive hydroxyl-terminated hyperbranched polyether (HTHP 2) was successfully prepared via a one-pot cationic polymerization technique and postmodification. In the first step, hydroxyl-terminated hyperbranched polyether containing double bonds (HTHP 1) were synthesized. Then, through thiol-ene “click” reaction, pH-responsive carboxyl groups were introduced to the target polymer of HTHP 2. The products were characterized via Fourier-transform infrared spectra (FTIR), nuclear magnetic resonance (NMR), and size-exclusion chromatography-multiangle laser light scattering (SEC-MALLS). Moreover, dynamic light scattering (DLS) and UV–Vis spectroscopy was employed to study the pH- and thermoresponsiveness in detail. Results showed that HTHP 2 possessed typical pH-controllable thermoresponsive behavior. By regulating the solution pH value range 3.0–5.4, LCST of HTHP 2 could be changed from 12.8 to 68.0 °C. Meanwhile, the cell viabilities of A549 cells were more than 80% for in vitro cytotoxicity tests of HTHP 2, suggested that HTHP 2 polymers are of good biocompatibility for up to 24 h.

Synthesis of Aliphatic Hyperbranched Polycarbonates via Organo-Catalyzed “A1+B2”-Ring-Opening Polymerization

“…42,43 Fan et al reported a hyperbranched polyether with thermo-and pH-responsiveness via "one-pot" cationic SCROP. 38 In an early study, Zhuo et al adopted the idea of SCROP for the preparation of a PEGattached multiarm aliphatic HBPC, which showed high micellar stability, a high doxorubicin loading content, and sustained release properties. 32 By exploiting a similar strategy, Parzuchowski and coworkers have developed a fluorinated HBPC and investigated its solubility in carbon dioxide.…”

“…Sun et al described the synthesis of hyperbranched polycarbonates (HBPCs) by a one-pot “A 2 +B 3 ” condensation polymerization of triols with dimethyl carbonate (DMC) . Furthermore, the self-condensing ring-opening polymerization (SCROP) of hydroxyl-terminated cyclic monomers is one of the most investigated strategies to straightforwardly access HBPs, especially for hyperbranched polycarbonates, − polyethers, − polyesters, , and polyphosphoesters. , Fan et al reported a hyperbranched polyether with thermo- and pH-responsiveness via “one-pot” cationic SCROP . In an early study, Zhuo et al adopted the idea of SCROP for the preparation of a PEG-attached multiarm aliphatic HBPC, which showed high micellar stability, a high doxorubicin loading content, and sustained release properties .…”