Thermoresponsive behavior of block copolymers of PEO and PNIPAm with different architecture in aqueous solutions: a study by NMR, FTIR, DSC and quantum-chemical calculations

0476789 - ÚMCH 2018 RIV GB eng J - Journal Article
Spěváček, Jiří - Konefal, Rafal - Dybal, Jiří - Čadová, Eva - Kovářová, Jana
Thermoresponsive behavior of block copolymers of PEO and PNIPAm with different architecture in aqueous solutions: a study by NMR, FTIR, DSC and quantum-chemical calculations.
European Polymer Journal. Roč. 94, September (2017), s. 471-483. ISSN 0014-3057. E-ISSN 1873-1945
R&D Projects: GA ČR(CZ) GA15-13853S
Institutional support: RVO:61389013
Keywords : thermoresponsive polymer * diblock copolymer PEO-b-PNIPAm * y-shape triblock copolymer PEO-b-(PNIPAm)2
OECD category: Polymer science
Impact factor: 3.741, year: 2017

Temperature behavior of D2O solutions of thermoresponsive diblock poly(ethylene oxide) (PEO)-b-poly(N-isopropylacrylamide) (PNIPAm) copolymers and Y-shape triblock PEO-b-(PNIPAm)2 copolymers was investigated and compared with the phase transition of the PNIPAm homopolymer by combination of NMR and ATR FTIR spectroscopy, DSC and model quantum-chemical calculations. It is shown that the phase transition and structures of PNIPAm component (forming micellar cores) are significantly affected not only by the presence of the PEO block but also by copolymer architecture. Both these factors affect energetics of the phase transition, influence of the polymer concentration and behavior of bound water at elevated temperatures. They also affect the degree of dehydration of PNIPAm segments (CO groups) at temperatures above the phase transition which is higher for block copolymers (especially for the diblock) in comparison with PNIPAm homopolymer. NOESY NMR spectra likewise revealed influence of the architecture of the block copolymer on its conformational behavior in the pretransition region.
Permanent Link: http://hdl.handle.net/11104/0273735