title: Phase Behavior of Nonionic Microemulsions with Multi-end-capped Polymers and Its Relation to the Mesoscopic Structure.
abstract: The polymer architecture of telechelic or associative polymers has a large impact on the bridging of self-assembled structures. This work presents the phase behavior, small angle neutron scattering (SANS), dynamic light scattering (DLS), and fluorescence correlation spectroscopy (FCS) of a nonionic oil-in-water (O/W) microemulsion with hydrophobically end-capped multiarm polymers with functionalities f = 2, 3, and 4. For high polymer concentrations and large average interdroplet distance relative to the end-to-end distance of the polymer, d/R(ee), the system phase separates into a dense, highly connected droplet network phase, in equilibrium with a dilute phase. The extent of the two-phase region is larger for polymers with similar length but higher f. The interaction potential between the droplets in the presence of polymer has both a repulsive and an attractive contribution as a result of the counterbalancing effects of the exclusion by polymer chains and bridging between droplets. This study experimentally demonstrates that higher polymer functionalities induce a stronger attractive force between droplets, which is responsible for a more extended phase separation region, and correlate with lower collective droplet diffusivities and higher amplitude of the second relaxation time in DLS. The viscosity and the droplet self-diffusion obtained from FCS, however, are dominated by the end-capped chain concentration.
authors: †Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 124, Sekr. TC7, 10623 Berlin, Germany.
authors: Paula Malo
authors: PM
authors: de Molina
authors: †Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 124, Sekr. TC7, 10623 Berlin, Germany.
authors: Franziska Stefanie
authors: FS
authors: Ihlefeldt
authors: †Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 124, Sekr. TC7, 10623 Berlin, Germany.|‡Soft Matter Department, Helmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany.
authors: Sylvain
authors: S
authors: Prévost
authors: §Fraunhofer Institut für Angewandte Polymerforschung IAP, Geiselbergstrasse 69, 14476 Potsdam-Golm, Germany.|∥Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm, Germany.
authors: Christoph
authors: C
authors: Herfurth
authors: ⊥Jülich Centre for Neutron Science (JCNS), Forschungszentrum Jülich GmbH, Outstation at MLZ, Lichtenbergstrasse 1, 85747 Garching, Germany.
authors: Marie-Sousai
authors: MS
authors: Appavou
authors: §Fraunhofer Institut für Angewandte Polymerforschung IAP, Geiselbergstrasse 69, 14476 Potsdam-Golm, Germany.|∥Institut für Chemie, Universität Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam-Golm, Germany.
authors: André
authors: A
authors: Laschewsky
authors: †Stranski-Laboratorium für Physikalische und Theoretische Chemie, Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 124, Sekr. TC7, 10623 Berlin, Germany.
authors: Michael
authors: M
authors: Gradzielski