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Poly(N-isopropylacrylamide)-SiO2 nanocomposites interpenetrated by starch: Stimuli-responsive hydrogels with attractive tensile properties

SYSNO ASEP	0471497
Document Type	J - Journal Article
R&D Document Type	Journal Article
Subsidiary J	Článek ve WOS
Title	Poly(N-isopropylacrylamide)-SiO2 nanocomposites interpenetrated by starch: Stimuli-responsive hydrogels with attractive tensile properties
Author(s)	Depa, Katarzyna (UMCH-V) Strachota, Adam (UMCH-V)_{RID, ORCID} Šlouf, Miroslav (UMCH-V)_{RID, ORCID} Brus, Jiří (UMCH-V)_{RID, ORCID}
Source Title	European Polymer Journal. - : Elsevier - ISSN 0014-3057 Roč. 88, March (2017), s. 349-372
Number of pages	24 s.
Language	eng - English
Country	GB - United Kingdom
Keywords	PNIPAm hydrogel ; starch ; silica
Subject RIV	CD - Macromolecular Chemistry
OECD category	Polymer science
R&D Projects	LD14010 GA MŠMT - Ministry of Education, Youth and Sports (MEYS)
Institutional support	UMCH-V - RVO:61389013
UT WOS	000396952500031
EID SCOPUS	85012149780
DOI	10.1016/j.eurpolymj.2017.01.038
Annotation	Doubly filled nanocomposite poly(N-isopropylacrylamide)-SiO2-starch hydrogels were prepared via simultaneous polymerization of N-isopropylacrylamide (NIPAm) and tetramethoxysilane hydrolysis, in the presence of colloid amylopectin starch (4–30 wt.% in dry gel). Besides bulk hydrogels, also highly porous ones were prepared, the latter via solvent freezing during synthesis (cryogels). The branched starch molecules, which interpenetrate PNIPAm, appear to enforce less crosslinked but more regular PNIPAm network with a wider mesh, in place of the irregular one, which is normally obtained in divinyl-crosslinked PNIPAm. The hydroxyl groups of starch form efficient hydrogen bonds to the PNIPAm matrix, as well as to the SiO2 nanofiller, which in turn also has strong H-bonds to PNIPAm. In bulk gels, a strong synergy of both fillers is clearly observed, leading to a marked increase in moduli, in spite of the wider network mesh. Very distinct is the improvement of tensile properties if starch is incorporated: the elongation at break increases 2 times in porous gels and 3–6 times in bulk ones. The gels’ toughness is also tremendously improved. The porous PNIPAm-SiO2-starch gels further display an ultra-fast swelling response to temperature jumps, both deswelling and re-swelling. Interestingly, starch-rich bulk PNIPAm-starch and PNIPAm-SiO2-starch gels also display a very fast (and also very extensive) temperature-induced deswelling, while their re-swelling is very slow (as would be expected). This behaviour practically represents a strong ‘one way response’ to temperature jumps. The specific properties of the interface between swollen PNIPAm and starch enable the rapid water escape from the bulk gels, especially if starch-rich domains are present.
Workplace	Institute of Macromolecular Chemistry
Contact	Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358
Year of Publishing	2017

Number of the records: 1