Morphology analysis of sodium chloride crystallization on the mica substrate using atomic force microscope.

Abstract

The morphology of the specific face growth of sodium chloride (NaCI) crystal on the mica surface was analyzed using atomic force microscope (AFM). The supersaturation of the NaCI was induced to lead to the crystal nucleation and growth by the addition of methylalcohol. The effects of methylalcohol concentration and mica surface functionality on the NaCI crystal growth morphology were investigated. The crystalline nucleus was formed scaterringly on the mica surface at 10% methylalcohol. It was grown laterally at 20% methylalcohol and agglomerated at 30% methylalcohol before lateral growth. The difference in the crystallization efficiency originated from the surface conditions is discussed by comparison of the crystallizations on surfaces of the bare mica and mica treated with Mg2+, 3-aminopropyltriethoxysilane, and ethyltriethoxysilane. The lateral growth of sodium chloride crystal was restricted by the different treatment of the mica surface. From these results, it was known that sodium chloride crystal growth morphology could be controlled by using additional solvent and substrate surface treatment. These results imply that the morphology analysis as well as reaction kinetics should be conducted in the crystallization analysis.