Poly[(N-isopropylacrylamide-co-acrylamide-co-(hydroxyethylmethacrylate))] thermoresponsive microspheres: An accurate method based on solute exclusion technique to determine the volume phase transition temperature

G. Fundueanu, M. Constantin, F. Bortolotti, R. Cortesi, P. Ascenzi, E. Menegatti

Research output: Contribution to journalArticlepeer-review

Abstract

Poly[(N-isopropylacrylamide-co-acrylamide-co-(hydroxyethylmethacrylate))] [poly(NIPAAm-co-AAm-co-HEMA)] copolymer was synthesized as a new thermoresponsive material possessing a lower critical solution temperature (LCST) around 37 °C in phosphate buffer, pH 7.4, at a solution concentration of 1%, w/v. The influence of polymer concentration on LCST was determined by cloud point measurements and by microcalorimetric analysis. The copolymer was transformed in hydrogel microspheres by suspension reticulation of {single bond}OH groups with glutaraldehyde. The volume phase transition temperature (VPTT) of microspheres was determined by a new approach, which involves measurement of the increase in concentration of a blue dextran (BD) solution at different temperatures in the presence of dry microspheres. The minimum BD concentration that gives reliable and reproducible results was determined to be 1 mg/ml. However, the higher is the concentration of BD in solution the smaller is the error. Contrary to solution of the linear polymer which displays a sharp phase transition temperature, the dependence of water regain of the hydrogel with temperature lasts from 4 °C to 50 °C.

Original languageEnglish
Pages (from-to)3500-3509
Number of pages10
JournalEuropean Polymer Journal
Volume43
Issue number8
DOIs
Publication statusPublished - Aug 2007

Keywords

  • Blue dextran
  • Equilibrium swelling ratio
  • Lower critical solution temperature
  • pH/Thermoresponsive copolymers
  • Volume phase transition temperature

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

Fingerprint Dive into the research topics of 'Poly[(N-isopropylacrylamide-co-acrylamide-co-(hydroxyethylmethacrylate))] thermoresponsive microspheres: An accurate method based on solute exclusion technique to determine the volume phase transition temperature'. Together they form a unique fingerprint.

Cite this