Electric field-induced self-assembly of micro- and nanoparticles of various shapes at two-fluid interfaces

Muhammad Janjua, Sai Nudurupati, Pushpendra Singh, Nadine Aubry

Research output: Contribution to journalArticlepeer-review

20 Scopus citations

Abstract

Particle lithography which explores the capability of particles to self-assemble offers an attractive means to manufacture nanostructured materials. Although traditional techniques typically lead to the formation of dense crystals, adjustable non-close-packed crystals are crucial in a number of applications. We have recently proposed a novel method to assemble spherical micro- and nanoparticles into monolayers. The technique consists of trapping particles at a liquid-fluid interface and applying an electric field normal to the interface. Particles rearrange themselves under the influence of interfacial and electrostatic forces to form 2-D hexagonal arrays of long-range order and whose lattice constant depends on the electric field strength and frequency. Furthermore, the existence of an electric field-induced capillary force makes the technique applicable to submicron and nanosized particles. Although spherical particles are often used, non-spherical particles can be beneficial in practice. Here, we review the method, discuss its applicability to particles of various shapes, and present results for particles self-assembly on air-liquid and liquid-liquid interfaces. In the case of non-spherical particles, the self-assembly process, while still taking place, is more complex as particles experience a torque which causes them to rotate relative to one another. This leads to a final arrangement displaying either a dominant orientation or no well-defined orientation. We also discuss the possibility of dislodging the particles from the interface by applying a strong electric field such that the Weber number is of order 1 or larger, a phenomenon which can be utilized to clean particles from liquid-fluid surfaces.

Original languageEnglish (US)
Pages (from-to)518-526
Number of pages9
JournalElectrophoresis
Volume32
Issue number5
DOIs
StatePublished - Feb 1 2011

All Science Journal Classification (ASJC) codes

  • Analytical Chemistry
  • Biochemistry
  • Clinical Biochemistry

Keywords

  • Capillary forces
  • Colloids
  • Fluid interfaces
  • Monolayers
  • Particle lithography

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