Polycation-PEG Block Copolymer Undergoes Stepwise Phase Separation in Aqueous Triflate Solution.

Vikram Baddam, Vladimir Aseyev, Sami Hietala, Erno Karjalainen, Heikki Tenhu (Corresponding Author)

Research output: Contribution to journalArticleScientificpeer-review

9 Citations (Scopus)

Abstract

A block copolymer poly(ethylene glycol)-b-poly(vinylbenzyltrimethylammonium triflate), PEG-PVBTMA-OTf, and a homopolymer PVBTMA-OTf were synthesized through RAFT reactions. The polymers were studied in aqueous triflate solutions with varying temperatures, changing also the polymer and salt concentrations. The hydrophobic triflate anion turns polycations thermoresponsive, and they show an UCST. In the block copolymer, the interaction between the PEG and the cationic block makes the phase separation occur in distinct steps. Upon cooling, transparent solutions first turn turbid and then partially clear at T cL. The T cL is not observed in a mixed solution of PVBTMA-OTf and PEG macro-CTA. By considering the interplay between ionic, hydrogen bonding, and hydrophobic interactions, an overall picture of the complex phase separation processes is suggested.

Original languageEnglish
Pages (from-to)9681-9691
Number of pages11
JournalMacromolecules
Volume51
Issue number23
DOIs
Publication statusPublished - 2018
MoE publication typeA1 Journal article-refereed

Keywords

  • Polyoxyalkylenes Role: PRP (Properties)
  • SPN (Synthetic preparation)
  • PREP (Preparation) (polycation-
  • diblock
  • stepwise phase sepn. of ethylene oxide-vinylbenzyltrimethylammonium triflate block copolymer in aq. triflate soln.)
  • Cloud point
  • Phase diagram
  • Phase separation
  • Turbidity (stepwise phase sepn. of ethylene oxide-vinylbenzyltrimethylammonium triflate block copolymer in aq. triflate soln.)
  • Critical solution temperature (upper
  • polycation
  • ethylene
  • oxide
  • copolymer
  • phase
  • sepn
  • aq
  • triflate

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