title: Optical properties of thermally responsive amphiphilic gold nanoparticles protected with polymers.
abstract: 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.
authors.affiliation: Laboratory of Polymer Chemistry, University of Helsinki, PB 55, FIN-00014 HY, Finland.
authors.forename: Jun
authors.initials: J
authors.lastname: Shan
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.forename: Markus
authors.initials: M
authors.lastname: Nuopponen
authors.forename: Tapani
authors.initials: T
authors.lastname: Viitala
authors.forename: Hua
authors.initials: H
authors.lastname: Jiang
authors.forename: Jouko
authors.initials: J
authors.lastname: Peltonen
authors.forename: Esko
authors.initials: E
authors.lastname: Kauppinen
authors.forename: Heikki
authors.initials: H
authors.lastname: Tenhu