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Characterization of 2D colloid aggregations created by optically induced electrohydrodynamics
Author(s) -
Work Andrew H.,
Williams Stuart J.
Publication year - 2015
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.201500111
Subject(s) - electrohydrodynamics , electrokinetic phenomena , particle (ecology) , electric field , dipole , laser , colloid , polystyrene , materials science , polarizability , molecular physics , analytical chemistry (journal) , optics , nanotechnology , chemistry , chromatography , physics , composite material , oceanography , organic chemistry , quantum mechanics , molecule , geology , polymer
Rapid electrokinetic patterning (REP) is a technique for creating self‐assembled monolayers (SAMs) of spherical particles in a liquid medium, and dynamically controlling them though the simultaneous application of an electric field and optically induced temperature gradients. Previous work has investigated and characterized REP axisymmetric aggregations generated from a focus laser within a uniform electric field; work herein characterizes line‐shaped particle assemblies derived from the application of a linearly scanned laser. The resulting aggregations of spherical polystyrene particles (1 μm) suspended in low‐conductivity aqueous potassium chloride solution (KCl, 2.5 mS/m) resembled elliptical‐shaped crystalline geometries. The mean particle‐to‐particle spacing within the aggregation remained greater than 1.5 diameters for experiments herein (6.5 V rms , 30 kHz) due to dipole–dipole repulsive forces. Interparticle spacing demonstrated a linear relationship (1.6–2.1 μm) with increasing scanning lengths (up to 83 μm), decreased from 1.9 to 1.7 μm with increasing scanning frequency (0.38–16 Hz) for a 53 μm scan length, and decreased from 2.0 to 1.6 μm with increasing laser power (11.9–18.8 mW) for a 59 μm, 16 Hz laser scan.