2‑(Benzylthio)ethyl\nGlycidyl Ether: A Gateway\nto Redox-Responsive Polyethers

This work presents the design and synthesis of a functional\nepoxide\nmonomer, 2-(benzylthio)ethyl glycidyl ether (BTGE), serving as a versatile\nbuilding block for the development of redox-responsive polyethers.\nIt details the successful synthesis of a series of poly(2-(benzylthio)ethyl\nglycidyl ether) (PBTGE) homopolymers and ABA-type triblock copolymers\n(i.e., PBTGE-<i>b</i>-PEO-<i>b</i>-PBTGE), achieved\nthrough controlled anionic ring-opening polymerization of the BTGE\nusing a poly(ethylene oxide) (PEO) macroinitiator. Comprehensive characterization\nof the synthesized monomers and polymers was performed employing various\nanalytical techniques, such as <sup>1</sup>H- and <sup>13</sup>C NMR,\nGPC, FT-IR spectroscopy, and MALDI-ToF mass spectrometry. These polymers\ndemonstrate unique redox-responsive behavior, characterized by an\noxidation-induced transition from hydrophobic to hydrophilic states\nand a reductive deprotection to generate free thiol groups. Furthermore,\nthe PBTGE-<i>b</i>-PEO-<i>b</i>-PBTGE triblock\ncopolymers have been utilized to form physically cross-linked hydrogels\nthrough the strong hydrophobic interactions of the end blocks. Notably,\nthese hydrogels undergo a gel-to-sol transition under oxidative conditions,\nas evidenced by rheological analysis. This study highlights the potential\nof the BTGE monomer as a versatile building block for the development\nof advanced materials with dual redox-responsive functionalities.