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Contrast variation SANS measurement of shell monomer density profiles of smart core-shell microgels
被引:16
|作者:
Cors, Marian
[1
,2
]
Wiehemeier, Lars
[1
]
Wrede, Oliver
[1
]
Feoktystov, Artem
[3
]
Cousin, Fabrice
[4
]
Hellweg, Thomas
[1
]
Oberdisse, Julian
[2
]
机构:
[1] Bielefeld Univ, Dept Phys & Biophys Chem, Univ Str 25, D-33615 Bielefeld, Germany
[2] Univ Montpellier, CNRS, L2C, F-34095 Montpellier, France
[3] Forschungszentrum Julich, Julich Ctr Neutron Sci JCNS Heinz Maier Leibnitz, D-85748 Garching, Germany
[4] CEA Saclay, CNRS, UMR 12, Lab Leon Brillouin,UMR 12, F-91191 Gif Sur Yvette, France
来源:
关键词:
SMALL-ANGLE SCATTERING;
COPOLYMER MICROGELS;
PHASE-TRANSITION;
TEMPERATURE;
PARTICLES;
BEHAVIOR;
HOLLOW;
NANOPARTICLES;
MORPHOLOGY;
COLLOIDS;
D O I:
10.1039/c9sm02036e
中图分类号:
O64 [物理化学(理论化学)、化学物理学];
学科分类号:
070304 ;
081704 ;
摘要:
The radial density profile of deuterated poly(N,n-propyl acrylamide) shell monomers within core-shell microgels has been studied by small-angle neutron scattering in order to shed light on the origin of their linear thermally-induced swelling. The poly(N-isopropyl methacrylamide) core monomers have been contrast-matched by the H2O/D2O solvent mixture, and the intensity thus provides a direct measurement of the spatial distribution of the shell monomers. Straightforward modelling shows that their structure does not correspond to the expected picture of a well-defined external shell. A multi-shell model solved by a reverse Monte Carlo approach is then applied to extract the monomer density as a function of temperature and of the core crosslinking. It is found that most shell monomers fill the core at high temperatures approaching synthesis conditions of collapsed particles, forming only a dilute corona. As the core monomers tend to swell at lower temperatures, a skeleton of insoluble shell monomers hinders swelling, inducing the progressive linear thermoresponse.
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页码:1922 / 1930
页数:9
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