Berlin 2018 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 32: Poster Session II

CPP 32.4: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster B

Janus emulsions and Janus gels stabilized by polyelectrolyte complexes — •Rajarshi Roy Raju, Sabine Kosmella, and Joachim Koetz — Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, D-14476, Potsdam, Germany

Janus emulsion is a special kind of emulsions which contains emulsion droplets composed by two hemispheres of immiscible oils surrounded by water. Our research activities deal with the formation of Janus emulsions through moderate-energy vibrational emulsification of olive oil and silicone oil in presence of polyelectrolytes, polyelectrolyte complexes and metallic nanoparticles stabilizing the individual oil droplets. Therefore, we have investigated the pH dependence of polyelectrolytes, e.g., chitosan, Na-carboxymethylcellulose (NaCMC), gelatin and Na-polyacrylate (NaPAA), and their possibility to form well defined polyelectrolyte complexes. By using chitosan one can find a pH-dependent fine-tuning of the Janus droplet size. By adding gelatine/NaPAA complex particles, varying in the particle size between 200 and 400 nm, it was possible to tune the Janus emulsion droplet diameter between 50 and 200 μm. Cryo-SEM images of the Janus droplets confirm the adsorption of complex particles on olive oil interface leading to a substantial decrease of the interfacial tension. Furthermore, Janus emulsion turns into a long-term stable Janus gel in presence of gelatine/NaCMC composites. In this case, Janus droplets remain embedded in the gel network and show elastic rheological behaviour along with noticeable thixotropic properties.