Regensburg 2013 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 34: Poster: Wetting, Micro and Nano Fluidics

CPP 34.15: Poster

Mittwoch, 13. März 2013, 16:30–18:30, Poster C

Study of the interface of droplets using pH change — •Birte Riechers, Quentin Brosseau, Florine Maes, and Jean-Christophe Baret — Max Planck Institute for Dynamics and Self-Organization, Göttingen, Germany

Interfaces are prevalent in many systems such as emulsions and foams. They can be stabilized using surfactant molecules. Amphiphilic molecules influence the properties of the interface (e.g. surface tension, interfacial rheology) as well as the bulk properties of the two phases (e.g. pH). The understanding of these properties is fundamental for the control of emulsion encapsulation for biological compartimentalization [Baret, Lab Chip 12 (2012), 422; Baret et al., Langmuir 25 (2009), 6088].

In our study, the effect of surfactants on the pH inside the droplets of emulsions is investigated. We combined a microfluidic fluorescence setup with a pH sensitive dye to monitor pH changes with time. Ionic surfactant molecules are dissolved in the continuous phase and upon adsorption to the interface release protons into the dispersed phase. Our results regarding the change of pH inside the droplets will bring quantitative information on interfacial surfactant coverage and thus allowing to conclude the stability of the interface for microencapsulation.