Design of CO2-responsive Pickering emulsions

Work package:
Pickering emulsions are dispersions of two immiscible fluids that are kinetically stabilized by colloidal particles. Silica or latex colloidal particles are generally use or particles endowed by catalytic properties when focus on the design of interfacial catalysts with special emphasis for industrial biphasic reactions in fine chemistry, in biofuel valorization or pollution control. However, the separation and recycling of nanocatalysts are challenges due to the high adsorption energy at the liquid-liquid interface. Therefore, it is possible to control the existence or destruction of these emulsions by reversibly modifying the affinity of the particles for the interface. This can be switched by applying a stimulus such as a change in pH induced by CO2. This stimulus is particularly attractive because it requires an environmentally friendly, simple and reversible operation. This project involves the preparation of Pickering emulsions by using an association of negatively charged gold nanoparticles and pH-responsive polymers formed in situ in the presence of CO2 starting from a tertiary amine. The reversible character of the emulsion will be evidenced under bubbling of CO2 and N2, alternatively. We propose to synthetize pH-responsive polymers bearing tertiary amine groups by raft polymerization. Different techniques will be used during this project: NMR, conductimetry, pHmetry, tensiometry, turbiditimetry, UV-vis spectroscopy, TEM, dynamic light scattering, zeta potential, contact angle measurements, Turbiscan.