Nanoparticle self-assembly at liquid-liquid interfaces (SALI): what's the point?

Self-assembly is found in uncountable natural phenomena and at all length scales. In recent times men have started to harness Nature’s self-organization to direct the assembly of materials and composites. Trapping at the interface, combined with lateral mobility and the presence of specific interactions, makes self-assembly of nanometer-sized colloids at liquid-liquid interfaces a process with huge potential for the creation of controlled “two-dimensional” structures and patterns and of novel ultrathin materials such as membranes and capsules. In particular, I will talk about two specific examples. Firstly I will explore the use of SALI for the deposition of non-close packed crystalline arrays for particle lithography to be used as a fabrication tool for nanoporous substrates for biosensing. The second example deals with the assembly of core-shell, metal oxide nanoparticles into ultrathin responsive membranes. I will initially focus on the kinetics of nanoparticle adsorption at the interface, both from a macroscopic (pendant drop tensiometry) and microscopic (passive microrheology) point of view. Then I will demonstrate preliminary examples of the fabrication of such membranes and of their mechanical characterization.