Optical properties of thermally responsive amphiphilic gold nanoparticles protected with polymers.
Amphiphilic thermally responsive gold nanoparticles have been prepared by protecting the particles with both polystyrene, PS, and poly(N-isopropylacrylamide), PNIPAM, chains. Particles form a monolayer on a water surface in a Langmuir trough, and according to in situ spectroscopic measurements, the surface plasmon resonance, SPR, band undergoes a blue-shift during the monolayer compression. The compression-induced blue-shift is related to a change in the conformation of tethered PNIPAM chains; the phenomenon is discussed on the basis of Mie-Drude theory. In contrast, a red-shift in the SPR of the multilayers of the same nanoparticles transferred at different temperatures has been observed with increasing the deposition cycle, attributed to the presence of a weak interparticle coupling in the multilayer.
Shan
Jun
J
Laboratory of Polymer Chemistry, University of Helsinki, PB 55, FIN-00014 HY, Finland.
Chen
Jie
J
Nuopponen
Markus
M
Viitala
Tapani
T
Jiang
Hua
H
Peltonen
Jouko
J
Kauppinen
Esko
E
Tenhu
Heikki
H