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Gelation mechanism of poly(N-isopropylacrylamide)-clay nanocomposite hydrogels synthesized by photopolymerization
- Source :
- Langmuir : the ACS journal of surfaces and colloids. 24(21)
- Publication Year :
- 2008
-
Abstract
- The gelation process of poly-(N-isopropylacrylamide)-clay nanocomposite hydrogels (PNIPAAm-clay NC gels) was investigated by dynamic and static light scattering (DLS and SLS), as well as by fluorescence correlation spectroscopy (FCS). The photopolymerization method chosen for the radical polymerizing system ensured that, when the irradiation is removed, the reaction stopped immediately. Experiments showed that shortly before the gelation threshold is reached, no changes in the DLS autocorrelation functions appear, while the monomer conversion can be observed by 1H NMR spectroscopy. These results correspond to the formation of microparticles, in which the PNIPAAm chains are closely attached to the clay platelets. During the further polymerization process, clay clusters are developed before the sol-gel threshold is reached. FCS measurements were performed to obtain information on the motion of the clay platelets inside the NC gel. The DLS method gives only an average of the motions in the gel. In a time window between 10 micros and 1 s, the clay sheets labeled with Rhodamine B show no characteristic motions.
- Subjects :
- inorganic chemicals
Nanocomposite
Materials science
technology, industry, and agriculture
Analytical chemistry
Fluorescence correlation spectroscopy
Surfaces and Interfaces
Condensed Matter Physics
complex mixtures
chemistry.chemical_compound
Monomer
Photopolymer
chemistry
Polymerization
Chemical engineering
Electrochemistry
Poly(N-isopropylacrylamide)
General Materials Science
Static light scattering
Spectroscopy
Sol-gel
Subjects
Details
- ISSN :
- 07437463
- Volume :
- 24
- Issue :
- 21
- Database :
- OpenAIRE
- Journal :
- Langmuir : the ACS journal of surfaces and colloids
- Accession number :
- edsair.doi.dedup.....e0df90dff1fb6c717fa6086ff37c974f