Thermally tunable catalytic and optical properties of gold-hydrogel nanocomposites.
We have developed a very simple approach for preparing physically embedded gold cores in a temperature-responsive hydrogel polymer nanoparticle under fluorescent light irradiation. The complete encapsulation of the multiple gold core nanoparticles is confirmed by the catalytic reduction of 4-nitrophenol, whose reactivity is significantly retarded above the lower critical solution temperature (LSCT) due to the deswelled polymer structure; its increased hydrophobicity slows the access of hydrophilic reactants to the cores. Since these gold cores are physically embedded in the polymer nanoparticles, further growth of the cores is reliably achieved in situ under light irradiation. Interestingly, the resulting composite nanoparticles exhibit reversible solution color changes as well as absorption bands from the visible to near-IR regions below and above the LSCT.
Department of Chemistry, Illinois State University, Normal, IL 61790-4160, USA. jkim5@ilstu.edu
Jun-Hyun
JH
Kim
Brett W
BW
Boote
Julie A
JA
Pham
Jiayun
J
Hu
Hongsik
H
Byun
D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D006358:Hot Temperature; D020100:Hydrogels / Q000737:chemistry*; D046911:Macromolecular Substances / Q000737:chemistry; D008422:Materials Testing; D008968:Molecular Conformation; D049329:Nanostructures / Q000737:chemistry* / Q000648:ultrastructure*; D010316:Particle Size; D012031:Refractometry; D013499:Surface Properties; D013817:Thermography / Q000379:methods*
D020100:Hydrogels; D046911:Macromolecular Substances; D006046:Gold