Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 4: Complex Fluids and Colloids I (joint session CPP/DY)

CPP 4.9: Talk

Monday, March 12, 2018, 11:45–12:00, C 264

Preparation of amphiphilic asymmetric patchy particles and their effect on emulsion properties — •Marco Rehosek, Akilavasan Jeganathan, and Frank Marlow — Max-Planck-Institut für Kohlenforschung, Mülheim an der Ruhr/Germany

Asymmetric patchy particles (APPs) have two different functionalities on the opposing sides of such a micro- or nanoparticle. These functionalities can be of a magnetic, chemical, or optical nature. Here we study different chemical polarities. Amphiphilic APPs having hydrophobic and hydrophilic regions show interesting performance as emulsifying agent. This effect enhances the so-called Pickering stabilization resulting in a "breathable skin" at a liquid|liquid interface.

In this work, the preparation of amphiphilic APPs and their effect on emulsions is studied. Titania&organosilane APPs were prepared via a wax-masking-symmetry breaking step. The unmasked part was modified by vapor deposition. The effect of the APPs on emulsion stability and aging effects of APP-stabilized emulsions was studied qualitatively by liquid-phase-distribution measurements. For a deeper understanding, rheological properties of the emulsions were investigated. Viscosimetry gave information on stress-dependent viscosity effects, while oscillation measurements reveal the viscoelastic properties. Long-time measurements resulted in information on aging processes in the emulsion i.e. creaming, coalescence and Ostwald ripening.