Scalable manufacturing of nanomaterials and novel classes on soft matter based on biphasic liquid systems

Orlin Velev, Chemical and Biomolecular Engineering, North Carolina State University, Raleigh NC, USA


We will discuss strategies for using multiphasic fluid systems in novel smart foams, emulsions and gels, as well as in the manufacturing of various classes of nanomaterials. In the first part of the talk we will present a few types of very stable, yet stimuli-responsive, Pickering foams. These foams are stabilized by rod-like polymer particles or ones made from hydrophobically modified cellulose. By addition of iron particles into the matrix, these Pickering systems can be made photo- as well as thermally sensitive. In the second part of the talk, we will describe a new smart gel system of ultra-flexible chains formed by magnetically responsive nanoparticles inside multiphase water-oil systems. The nanoparticles are coated by condensed, surface-anchored lipid shells. The field collects the super-paramagnetic nanoparticles into filaments, while the liquid lipid shells form nanocapillary bridges on contact. The nanocapillary binding allows for easy particle rolling and sliding and the resulting flexibility is orders of magnitude higher than other linear structures reported to date. The soft, "snappable," capillary interactions enable the directional assembly of patchy particles and making of magnetically self-repairing gels and novel inks for 3D printing. Finally, we will discuss how polymer precipitation under shear in biphasic liquid systems can be used in the development of scalable, rapid and efficient processes for nanomaterials synthesis. The ultralow interfacial tension between oil droplets and shear medium enables the formation of diverse classes of nanomaterials with high surface area. Our "shear nanospinning" technique opens the way to scalable manufacture of nanofibers. One modification of the method yields an interesting new material in the form of hierarchically structured dendrimeric polymer particles with a broad range of potential applications.