la404961p_si_001.pdf (2.39 MB)
Length Fractionation of Boron Nitride Nanotubes Using Creamed Oil-in-Water Emulsions
journal contribution
posted on 2014-02-25, 00:00 authored by Yiu-Ting
R. Lau, Maho Yamaguchi, Xia Li, Yoshio Bando, Dmitri Golberg, Françoise M. WinnikThe fractionation by length of multiwalled
boron nitride nanotubes
(BNNTs) was achieved by emulsification and creaming of an oil/water/surfactant
mixture. The length separation is based on the fact that nanoparticle-coated
oil droplets polydisperse in size move toward the upper surface or
the bottom of an emulsified mixture depending on the density of the
droplets, such that droplets of different sizes are located at different
heights. By sampling heightwise an unstable hexane/water/Tween 20/BNNT
(1–20 μm long) emulsion, we observed that the lengths
of the BNNTs adsorbed on the droplets display a strong correlation
with the droplets sizes, thus leading to selective separation of the
BNNT lengths, as confirmed by dark-field optical imaging and dynamic
light scattering. This method may potentially be extended to other
high aspect ratio nanomaterials exhibiting emulsification properties
similar to those of BNNTs.