Synthesis and Self-assembly of a Helical Polymer Grafted from a Foldable Polyurethane Scaffold

Ranajit Barman, Pradip Dey, Tathagata Mondal, Suhrit Ghosh*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Herein a polyurethane graft poly-l-glutamate amphiphilic copolymer was synthesized from a polyurethane (PU)-based macro-initiator (containing pendant primary amine groups) through the ring opening polymerization of N-carboxy anhydride of γ-benzyl-l-glutamate (BLG-NCA). On average, twenty two l-glutamic acids were grafted from each amino group which was pendant on the polyurethane chain with 10 repeating units. The grafted polymer (PU-PP-1) exhibits self-assembly to produce a hydrogel in a wide pH window ranging from pH 5.0 to 8.0 with a critical gelation concentration (CGC) of 5.0 wt % (w/v) at pH 7.4. Furthermore, circular dichroism study revealed the transition of the α-helix to a random coil upon increasing the pH. Due to the protonation of side chains at pH 4.0, PU-PP-1 adopted an α-helical conformation whereas at pH >8.0 the side-chain carboxylic acid groups of the PLGAs were ionized, leading to the formation of an extended random coil conformation as a result of charge repulsion. Conformational switching was also supported by FTIR spectroscopy.

Original languageEnglish
Pages (from-to)4741-4747
Number of pages7
JournalChemistry - An Asian Journal
Issue number24
StatePublished - 13 Dec 2019
Externally publishedYes


  • Brush polymers
  • Folding
  • Hydrogels
  • Polypeptides
  • Polyurethanes
  • pH-responsive self-assembly


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