Regensburg 2019 – wissenschaftliches Programm
DY 2.6: Vortrag
Montag, 1. April 2019, 10:45–11:00, H8
PNIPAM microgel-stabilized aqueous foams and foam films — •Matthias Kühnhammer and Regine von Klitzing — Technical University of Darmstadt, Soft Matter at Interfaces, Darmstadt, Germany
Cross-linked, short-chained poly-N-isopropylacrylamide (NIPAM) polymers have been in the focus of numerous studies in the past years and are still being discussed very actively in the context of multiple possible applications, because of their ability to respond to external stimuli like temperature. A prominent example are thermo-responsive emulsions stabilized by microgel particles adsorbed at the water-oil interface. In these systems the emulsion stability can be controlled by changing the temperature.
In this contribution the interfacial activity of PNIPAM microgels is exploited to stabilize aqueous foams. These foams are very stable at temperatures below the volume phase transition temperature (VPTT) of NIPAM and can be destabilized by increasing the temperature above the VPTT. In addition, the relation between the properties of individual microgels (e.g. size, elasticity, particle concentration) and the properties of foams prepared with them is studied. The properties of foam films are studied with a thin film pressure balance and are related to features of macroscopic foams investigated in drainage experiments and with neutron scattering.