SALINAME · Self-assembly of magnetic core-shell nanoparticles at liquid-liquid interfaces for the fabrication of ultra-thin responsive membranes

The goal of this project is to study and control the self-assembly of superparamagnetic iron oxide nanoparticles (NPs) stabilized by a shell of responsive polymers at liquid-liquid interfaces in order to crosslink them into ultra-thin, mechanically stable, responsive membranes. This novel “smart” material will have unique properties suitable for applications in miniaturized lab-on-chip and other microfluidics devices. The interdisciplinary nature of the project contributes to its scientific novelty and impact, and constitutes an extraordinary training experience for the applicant. In the first part of the project, the applicant will develop a novel combination of experimental techniques to characterize the fundamental aspects of core-shell NP adsorption at liquid-liquid interfaces. By means of advanced confocal microscopy and particle tracking, complemented by pendant-drop tensiometry, this project will yield an exhaustive characterization, both from a microscopic and macroscopic point of view, of such system, so far practically unexplored. The obtained understanding - of high scientific relevance in its own right - will be used to optimize the design and fabrication of crosslinked responsive NP monolayer membranes. Using superparamagnetic NPs stabilized by a shell of crosslinkable thermoresponsive polymers, the applicant will produce ultra-thin robust assemblies which can respond reversibly to external stimuli. Temperature changes and consequent responses can be imparted to the system locally by exploiting the magnetic functionality of the NP constituents (heat transfer in an AC magnetic field). Moreover the crosslinked membranes can be actuated in DC magnetic fields as envisaged for applications. The responsive properties of the resulting materials, which have no current equivalent, will be investigated by means of optical and atomic force microscopy (structural properties) and microrheology and colloid-AFM force spectroscopy (mechanical properties).