Effect of temperature on the association behavior in aqueous mixtures of an oppositely charged amphiphilic block copolymer and bile salt

Research output: Contribution to journalArticle

Abstract

The association in aqueous mixtures of a thermoresponsive cationic diblock copolymer composed of poly(N-isopropylacrylamide) (PNIPAM) and poly(3-acrylamidopropyl)-trimethylammonium-chloride (PAMPTMA(+)) and the oppositely charged bile salt sodium deoxycholate (NaDC) is investigated at different compositions by light and X-ray scattering, calorimetry, and electrophoretic mobility measurements. Clouding reveals aggregation upon heating. The addition of NaDC to the copolymer solution lowers the temperature of the transition and increases its cooperativity. At high temperature and low NaDC fractions, mixed aggregates with a dehydrated PNIPAM-rich interior and a PAMPTMA(+)-rich shell partially neutralized by DC anions are formed. At high NaDC fractions, the aggregates present internal regularly spaced segregated nanoregions of dehydrated PNIPAM and PAMPTMA(+)/DC (microphase separation). The results suggest that the mixed aggregates have appealing composition-controlled thermoresponse. The system phase separates at body temperature and the highest NaDC fractions investigated, meaning in conditions accomplished when the use of the polymer as a bile salt sequestrant is hypothesized.

Details

Authors
Organisations
External organisations
  • Sapienza University of Rome
  • University of Campinas
  • University of Oslo
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Physical Chemistry

Keywords

  • Bile salts, Cationic thermoresponsive block copolymers, Oppositely charged polymer-surfactant systems
Original languageEnglish
Article number122871
JournalPolymer
Volume206
Publication statusPublished - 2020
Publication categoryResearch
Peer-reviewedYes