Regensburg 2010 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 37: Poster: Colloids and Complex Liquids
CPP 37.6: Poster
Mittwoch, 24. März 2010, 17:30–19:00, Poster B2
Transient melting of binary glasses by hot gold colloids — •Florian Schwaiger and Werner Köhler — Universität Bayreuth, Physikalisches Institut, 95440 Bayreuth
Gold colloids with a diameter of 250 nm can be heated by laser irradiation and have been used as microscopic heat sources in near-critical polymer blends (poly(ethyl-methyl siloxane)/poly(dimethyl siloxane)) and in concentrated polystyrene/toluene solutions close to the glass transition. Due to the high absorbance at the plasmon resonance wavelength (λ≈ 532 nm), significant temperature gradients ∇ T∝ 1/r2 can be achieved in the close vicinity of the particles on length scales below the diffraction limit. As a consequence of the Soret effect, there is a strong coupling to the order parameter, the local composition of the binary system. Colloids immobilized at a surface have been used to induce composition patterns in the polymer blend. In the binary glass former, a bubble of high mobility due to local toluene enrichment, accompanied by a lowering of Tg, is formed around and moves together with the colloidal particle.