Dresden 2014 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe

CPP: Fachverband Chemische Physik und Polymerphysik

CPP 39: Active Colloids

CPP 39.4: Vortrag

Donnerstag, 3. April 2014, 10:30–10:45, ZEU 260

Size dependent efficiency of optically heated Janus Particles. — •Andreas Bregulla and Frank Cichos — Universität Leipzig, Deutschland

For nanoscale manipulations in liquids Brownian motion is a limiting factor. In nature various transport mechanisms have evolved which overcome the Brownian fluctuations. Recently, a number of model swimmer have been fabricated and shown to provide similar function. However, hardly no detailed experimental study of their swimming efficiency exists. Here we investigate experimentally the efficiency of self-propelled photophoretic swimmers based on metal-coated polymer particles of different size. The metal hemisphere absorbs the incident laser power and converts its energy into heat, which dissipates into the environment. A phoretic surface flow arises from the temperature gradient along the particle surface and drives the particle parallel to its symmetry axis. Scaling the particle size from micro to nanometers the efficiency of converting optical power into motion is expected to rise with the reciprocal size for ideal swimmers.However, due to the finite size of the metal cap, the efficiency of a real swimmer reveals a maximum depending sensitively on the details of the metal cap shape. We compare the experimental results to numerical simulations.