Tuning the bis-hydrophilic balance of microgels: A tool to control the stability of water-in-water emulsions.

Hypothesis: The stability of purely aqueous emulsions (W/W) formed by mixing incompatible polymers, can be achieved through the Pickering effect of particles adsorption at the interface. However, there is, as yet, no guideline regarding the chemical nature of the particles to predict whether they will stabilize a particular W/W emulsion. Bis-hydrophilic soft microgels, made of copolymerized poly(N-isopropylacrylamide) (pNIPAM) and dextran (Dex), act as very efficient stabilizers for PEO/Dextran emulsions, because the two polymers have an affinity for each polymer phase.

Effect of charge on the stabilization of water-in-water emulsions by thermosensitive bis-hydrophilic microgels.

Hypothesis: Molecular surfactants are not able to stabilize water-in-water (W/W) emulsions, unlike nano or micro-particles, which can achieve this in some cases. However, the effect of electrostatic interactions between particles on the emulsion stability has rarely been investigated. We hypothesize that introducing charges modifies the stabilization capacity of particles and renders it both pH- and ionic strength-dependent.

Selective trapping of CO gas and cage occupancy in CO-N and CO-CO mixed gas hydrates.

Hydrate-based CO2 trapping from CO2-N2 and CO2-CO gas mixtures is shown by Raman spectroscopy - the results are of interest for new separation and capture technology. A better trapping efficiency is measured for low CO2 concentrations and N2-based gas mixtures. Moreover, it is observed that CO molecules would impede hydrate formation from ice when a CO-enriched gas mixture is considered.