Tag: Marcel Rey

Marcel Rey won best oral presentation at ECIS, Chania

ECIS 2022 conference logo. (Image by ECIS 2022.)
Marcel Rey won the prize for the best oral presentation at the European Colloid and Interface Society conference in Chania from 04.09.2022-09.09.2022. The award, consisting of 500 EUR, is offered by the affiliated MDPI open access journal of polymer science –  Polymers.

In the talk, Marcel presented his recent work on the destabilisation mechanism of temperature-responsive emulsions. He demonstrated that the presence or absence of stimuli-responsive emulsion behaviour is linked to the characteristic microstructure of the stabilising microgel particles. Surprisingly, only emulsions where the microgels are in a double-corona morphology show stimuli-responsive behaviour while emulsions stabilised with microgels in a single-corona morphology remain insensitive to temperature.

 

Presentation by M. Rey at ECIS 2022, Chania, 04 September 2022

Emulsion droplet stabilized by PNIPAM microgels. (Image by M. Rey.)
On the breaking mechanism of temperature-responsive emulsions
Marcel Rey
Submitted to ECIS 2022
Date: 05 September 2022
Time: 16:40 (CET)

Temperature-responsive microgel-stabilized emulsions combine long-term storage with controlled release of the encapsulated liquid upon temperature increase. The destabilisation mechanism was previously primarily attributed to the shrinkage or desorption of the temperature-responsive microgels, leading to a lower surface coverage inducing coalescence.
Here, we link the macroscopic emulsion stability to the thermo-responsive behaviour and microstructure of individual microgels confined at liquid interfaces and demonstrate that the breaking mechanism is fundamentally different to that previously anticipated. Breaking of thermoresponsive emulsions is induced via bridging points in flocculated emulsions, where microgels are adsorbed to two oil droplets. These bridging microgels induce an attractive force onto both interfaces when heated above their volume phase transition temperature, which induces coalescence. Surprisingly, if such bridging points are avoided by low shear emulsification, the obtained emulsion is insensitive to temperature and remains stable even up to 80 °C.

Marcel Rey joins the Soft Matter Lab

(Photo by A. Argun.)
Marcel Rey started his post-doc at the Physics Department of the University of Gothenburg on 1st August 2022. His research is funded by a Marie-Curie Individual Fellowship with Grant No. 101064381.

Marcel received a PhD degree in Chemical-Engineering from the Friedrich-Alexander University Erlangen-Nuremberg, Germany. In his thesis, he focused on the self-assembly behavior of soft colloidal particles confined at liquid interfaces.

In the Soft Matter Lab, Marcel will investigate the “Coffee Ring Effect”, a characteristic drying behavior of liquids containing dispersed particles. The goal is to find simple strategies towards homogeneous drying of particle dispersions.