Aluminium oxide nanoparticles prepared by water-in-oil microemulsions
Yongxin Pang
Xujin Bao
2134/22401
https://repository.lboro.ac.uk/articles/journal_contribution/Aluminium_oxide_nanoparticles_prepared_by_water-in-oil_microemulsions/9237050
A new water-in-oil microemulsion, consisting of the non-ionic surfactant Triton X-114, cyclohexane as the oil
phase and 1.0 M AlCl3 aqueous solution as the aqueous phase, was developed and used to synthesise
aluminium oxide (Al2O3) nanoparticles. The partial phase diagram of this ternary system was also determined
at 38 uC. Syntheses of Al2O3 nanoparticles were carried out in a range of microemulsions with a fixed
oil : surfactant ratio of 70 : 30 (w/w), but with different aqueous phase contents. For the purposes of
comparison, Al2O3 particles were also synthesised in the corresponding emulsion and by direct precipitation
from aqueous solution. Nano-sized Al2O3 particles were only obtained via microemulsions, whereas the
emulsion route led to hollow ball-shaped particles with sub-micron apparent sizes and the direct precipitation
process resulted in angular particles about 250 nm in dimension. The nanoparticles synthesised in the
microemulsion with 20 wt% aqueous phase content have smaller particle sizes (5–15 nm) and a lower
transformation temperature into a-form Al2O3 crystallites. Pure a-Al2O3 nanocrystals were obtained by
calcination at 1000 uC for 12 h, while the nano-sized dimension of the particles retained though the apparent
particle size increased to some extent. This transformation temperature is about 200 uC lower than that for the
Al2O3 particles synthesised by direct precipitation.
2016-09-12 11:41:07
Aluminium oxide
Microemulsions
Materials Engineering not elsewhere classified