Abstract: The small crystallites of quasi sphere aggregates NaNO₂ nano-particles prepared by normal ice sublimation method in ethanol were reassembled by ultrasonic vibration to form more stable square aggregates. A 0.5 kV/cm electric field vertically was applied to the sample while the ice was subliming. The results show that the electric field made some NaNO₂ crystallites exceed 6 nm in size, and to be discrete. We think it is the electric field to polarize the ferroelectric NaNO₂ crystallites. And the polarization of adjoining crystallites in the same direction led to the separated configuration. 

Key words: ice sublimation, electric field, NaNO₂, nano-particle