Dresden 2009 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 43: New Materials
CPP 43.7: Vortrag
Freitag, 27. März 2009, 12:00–12:15, ZEU 114
Multi-responsive hybrid colloids based on gold nanorods and poly-(NIPAM-co-allyl-acetic acid) microgels: temperature- and pH-tunable plasmon resonance — Matthias Karg1, Enrique Carbó-Argibay2, Isabel Pastoriza-Santos2, Jorge Pérez-Juste2, Luis Liz-Marzán2, and •Thomas Hellweg1 — 1Universität Bayreuth, Physikalische Chemie I, Universitätsstrasse 30, 95447 Bayreuth, Germany — 2Universidade de Vigo, Departamento de Quimica Fisica, 36310 Vigo, Spain
This work describes the reversible changes of the optical properties of multiresponsive organic/inorganic hybrid particle colloids, which consist of a thermoresponsive poly-(NIPAM-co-allylacetic acid) microgel core and gold nanorods adsorbed to their surface. These composites combine the interesting optical properties of the rod-shaped gold particles -- exhibiting two distinct pronounced plasmon modes -- with the sensitivity of the microgel toward external stimuli, such as temperature or solution pH. We show here that the collapse of the microgel core, induced by changes in either temperature or pH, enhances the electronic interactions between gold nanorods on the gel surface, as a result of the subsequent increase of packing density derived from the reduced surface of the collapsed microgel [1]. These interactions lead to remarkable redshifts of the longitudinal plasmon resonance, which can be as large as 50 nm.
[1]. Karg, I. Pastoriza-Santos, J. Perez-Juste, T. Hellweg, L. M. Liz-Marzan, Nanorod-coated PNIPAM microgels: Thermoresponsive optical properties. Small 2007, 3, 1222.