Berlin 2018 – wissenschaftliches Programm
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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 64: Nanostructures, Nanostructuring and Nanosized Soft Matter II
CPP 64.9: Vortrag
Donnerstag, 15. März 2018, 11:45–12:00, PC 203
Salt-induced microheterogeneities in binary liquid mixtures — •Markus Bier1, Julian Mars2, Hailong Li2, and Markus Mezger2 — 1Max Planck Instutite Int. Sys. and University of Stuttgart, Germany — 2Max Planck Institute Poly. Res. and University of Mainz, Germany
The formation of microheterogeneities (MHs) in binary liquid mixtures due to the presence of salt is investigated by means of small-angle X-ray scattering (SAXS) and liquid state theory. The phenomenon is experimentally known to occur for antagonistic salts, whose cations and anions prefer different components of the solvent mixture. However, up to now the origin of the characteristic length scale of MHs was unclear. In this contribution it is shown that MHs can be generated by an interplay between short-ranged interactions and long-ranged monopole-dipole interactions. This conclusion has been reached by performing SAXS measurements and comparing the solvent structure factor with a general expression derived without assuming any specific model. This method allows one to analyse the dependency of the MH structure with respect to ionic strength and temperature. Upon approaching the demixing phase transition, critical-like behaviour occurs close to the spinodal line in the phase diagram.
Reference:
M. Bier, J. Mars, H. Li & M. Mezger, Phys. Rev. E 96, 022603 (2017).