Scalable liquid-based manufacturing of new classes of particles with special shape and enhanced functionality
April 3-7, 2016
We will first discuss a number of scalable, rapid and cost-effective processes for the synthesis of new classes of particles and functional nanomaterials via antisolvent-induced biphasic polymer precipitation from solution under shear. The ultralow interfacial tension between the droplets and the medium enables the formation of high surface area liquid structures, which can serve as templates for the formation of diverse classes of polymer and biopolymer materials, at least one characteristic dimension of which may be on the nanoscale. Our “shear nanospinning” technique that operates on these principles opens the way to scalable manufacture of nanofibers and nanoribbons (Adv. Mater., 27, 2642, 2015). The fibers are formed in the bulk of liquid medium by the combined action of shear and phase separation. The corresponding patented technology commercialized as XanoShear™ may revolutionize the scale and scope of nanofiber application in consumer and industrial products.
After introducing the method principles, we will discuss two classes of novel particles made by this technique in Velev group, which could find applications in a broad range of consumer products. The method was originally used to make dispersions of polymer rods that can act as "superstabilizers" of Pickering foams and emulsions. Modifications of the technique allowed making new types of sheet-like and ribbon-like particles, which exhibit extraordinary strong jamming in suspension and can be used as highly efficient viscosity modifiers and matrixes for gels and aerogels. Finally, we present the making and properties of new class of environmentally-benign nanoparticles (EbNPs) with cores made of biodegradable lignin. These particles are fabricated by liquid shear process including water-only pH-jump precipitation. They can serve as highly potent microbicidal substitutes of common silver nanoparticles after being loaded with an optimal amount of silver in the form of adsorbed Ag+ ions (Nature Nanotech., 10, 817, 2015). The high antimicrobial efficiency of the EbNPs stems from a cationic surface modification of the particles that facilitates their adsorption onto bacterial membranes and triggers a targeted release of active Ag+ ions. These environmentally-benign nanoparticles illustrate how green chemistry principles can be applied to design more sustainable nanomaterials with increased activity and decreased environmental footprint.
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Orlin D. Velev, "Scalable liquid-based manufacturing of new classes of particles with special shape and enhanced functionality" in "Design and Manufacture of Functional Microcapsules and Engineered Products", Chair: Simon Biggs, University of Queensland (Aus) Co-Chairs: Olivier Cayre, University of Leeds, UK Orlin D. Velev, North Carolina State University, USA Eds, ECI Symposium Series, (2016). http://dc.engconfintl.org/microcapsules/10
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