title: Effect of Nanoparticle Surfactants on the Breakup of Free-Falling Water Jets during Continuous Processing of Reconfigurable Structured Liquid Droplets.
abstract: Structured liquids, whose 3-D morphology can adapt and respond to external stimuli, represent a revolutionary materials platform for next-generation energy technologies, such as batteries, photovoltaics, and thermoelectrics. Structured liquids can be crafted by the jamming of interfacial assemblies of nanoparticle (NP) surfactants. Due to the interactions between functional groups on nanoparticles dispersed in one liquid and polymers having complementary end-functionality dissolved in a second immiscible fluid, the anchoring of a well-defined number of polymer chains onto the NPs leads to the formation of NP surfactants that assemble at the interface and reduce the interfacial energy. Microfluidic techniques provide a simple and versatile route to produce one liquid phase in a second where the shape of the dispersed liquid phase can range from droplets to tubules depending on the flow conditions and the interfacial energies. In this study, the effect of NP surfactants on Plateau-Rayleigh (PR) instabilities of a free-falling jet of an aqueous dispersion of carboxylic acid functionalized silica NPs into a toluene phase containing amine-terminated polydimethylsiloxane (PDMS-NH2) is investigated. NP surfactants were found to significantly affect the breakup of laminar liquid jets, resulting in longer jet breakup lengths and dripping to jetting flow transitions.
authors.affiliation: Department of Mechanical Engineering, University of California , 6141 Etcheverry Hall, Berkeley, California 94720, United States.
authors.forename: Anju
authors.identifier: 0000-0002-8613-7547
authors.initials: A
authors.lastname: Toor
authors.forename: Brett A
authors.identifier: 0000-0003-3925-4174
authors.initials: BA
authors.lastname: Helms
authors.affiliation: Department of Polymer Science and Engineering, University of Massachusetts Amherst , 120 Governors Drive, Amherst, Massachusetts 01003, United States.|Beijing Advanced Innovation Center for Soft Matter Science and Engineering, Beijing University of Chemical Technology , Beijing 100029, China.
authors.forename: Thomas P
authors.identifier: 0000-0001-6384-5826
authors.initials: TP
authors.lastname: Russell
keywords: Plateau−Rayleigh instability; jetting; nanoparticles; structured liquids; surfactants