0395900 - ÚMCH 2014 RIV DE eng J - Journal Article
Šťastná, J. - Hanyková, L. - Sedláková, Zdeňka - Valentová, H. - Spěváček, Jiří
Temperature-induced phase transition in hydrogels of interpenetrating networks poly(N-isopropylmethacrylamide)/poly(N-isopropylacrylamide).
Colloid and Polymer Science. Roč. 291, č. 10 (2013), s. 2409-2417. ISSN 0303-402X. E-ISSN 1435-1536
R&D Projects: GA ČR GA202/09/1281
Institutional support: RVO:61389013
Keywords : temperature-induced volume phase transition * poly(N-isopropylmethacrylamide) poly(Nisopropylacrylamide) interpenetrating network * 1H NMR spectroscopy
Subject RIV: CD - Macromolecular Chemistry
Impact factor: 2.410, year: 2013

The combination of 1H NMR spectroscopy, DSC, dynamic mechanical spectroscopy, and optical microscopy was used to investigate temperature-induced volume phase transition in hydrogels of interpenetrating networks (IPNs) poly(N-isopropylmethacrylamide)/poly(N-isopropylacrylamide) (PNIPMAm/PNIPAm) with various PNIPMAm content. In these IPNs, both networks are thermosensitive; such systems were not examined so far. All methods showed phase transition starting at 307 K, which is the volume phase transition temperature of PNIPAm, the major network component. Only the sample with the lowest content of PNIPAm (~54 %) shows two-step collapse transition, other samples with higher PNIPAm content show a single transition in NMR and DSC which indicates enhanced mutual entanglement of both components. In all samples, the phase transition results in substantial increase of both components of the shear modulus. Although the properties of all samples change with temperature in similar way, differences in dependence on the PNIPMAm content and the shape of the sample can be seen.
Permanent Link: http://hdl.handle.net/11104/0225107