Dresden 2009 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 8: Nanoparticles I

CPP 8.1: Talk

Monday, March 23, 2009, 10:30–10:45, ZEU 114

Nanoscale pH-sensing with Polymer coated Gold Nanorods — •Irene Ament, Jan Becker, Andreas Henkel, Sebastian Pierrat, Luigi Carbone, and Carsten Sönnichsen — Institute for Physical Chemistry, University of Mainz, Germany

We report a reversible nanoscale pH-sensor consisting of a gold nanorod covered with the pH sensitive polymer Poly(acrylic acid). This polymer is covalently bound to the gold particle by cystein side groups and deprotonats under basic conditions. At high pH, the backbone is therefore stretched by the repelling forces of the negative charges and the packing becomes less dense, lowering the refractive index around the particle. This change in the refractive index induces a shift in the plasmon resonance, which we detect with single particle dark field spectroscopy. With such a reversible system we detect pH variations at the nanometer scale and could potentially map pH landscapes with high precision.