Berlin 2018 – scientific programme

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 33: Poster Session III

CPP 33.23: Poster

Tuesday, March 13, 2018, 14:00–16:00, Poster C

Pressure-induced phase separation in silica nanoparticle-polymer solutions — •Marc Moron, Julian Schulze, Julia Nase, Michael Paulus, and Metin Tolan — Fakultät Physik/DELTA, TU Dortmund, 44221 Dortmund, Germany

Nanoparticles are in the focus of current research because they are important for many applications like e.g. thermal energy storage or in medical chemistry for gene delivery. Silica nanoparticles in aqueous solution show a repulsive interaction. By adding small non-adsorbing polymers (e.g. polyethylene glycol), the total particle-particle interaction can become attractive. With increasing polymer concentration, the system undergoes a liquid-liquid phase separation. Further increase of the PEG concentration leads to a homogenous solution, which is explained by the repulsive interaction between the polymers. This concentration-dependent phase transition can also be achieved by exposing the system to high pressure. However, a complete understanding of the effect of pressure on the nanoparticle-polymer system is still missing. In this work light transmission and small-angle X-ray scattering (SAXS) measurements are performed, to study systematically the effect of hydrostatic pressure, the molecular weight of PEG and the sample environment on the phase behavior. In that way a complete picture of the system is obtained and the understanding of the phase transition on a microscopic level is increased.