Thermo-responsive highly branched polyethers by proton-transfer polymerization of 1,2,7,8-diepoxyoctane and multiols

Thermo-responsive highly branched polyethers were prepared via one-step proton-transfer polymerization of 1,2,7,8-diepoxyoctane (DEO) and multiols including ethylene glycol, di(Ethylene glycol), 1,2-propanediol, and glycerol. The degree of branching of the products obtained form DEO and oligo(ethylene glycol) is estimated to be 0.16-0.22. All highly branched polyethers exhibit a thermally induced phase transition in aqueous solution. The LCSTs of these polyethers can be tuned in the range of 23.6-67.2 degrees C. It is found that the hydrophilic/hydrophobic balance of the DEO and diols, the feed ratio of DEO to glycerol, and molecular weights play important role in controlling the LCST.