One pot synthesis and gelation studies of amphiphilic triblock polyurethanes

This article shows a generalized synthetic strategy to make amphiphilic ABA type triblock polyurethane (PU) in a SINGLE reaction pot. This is achieved by condensation polymerization between a hydrophobic diol and a di‐isocyanate in the presence of a polyethylene glycol monomethyl ether (Mw = 2000 or 5000 g mol−1) as mono‐functional impurity. Using different ratios of the three reactants with a fixed parameter such that the total concentration of –OH = isocyanate, a series of PUs are produced with both the ends capped with PEG. These polymers show facile gelation ability in solvents like dimethyl formamide, dimethyl sulfoxide, and dimethyl acetamide by H‐bonding interaction among the urethane groups. A comprehensive structure–property relationship study reveals importance of the right balance between the weight fractions of the soft and hard segments in self‐assembly and efficient gelation.