Preparation of Indium−Tin Oxide Particles in Shear-Induced Multilamellar Vesicles (Spherulites) as Chemical Reactors

Abstract

Spherulites, spherical multilamellar vesicles (300−10 000 nm in diameter), were formed by applying shear force to the mixture of two lamellar phases, containing inorganic salts (indium nitrate and tin chloride) in one lamellar phase (I) and a precipitating agent (ammonium hydroxide) in another lamellar phase (II). These spherulites were employed as a reaction medium to prepare the indium−tin hydroxide nanoparticles. The chemical reaction for the formation of indium−tin hydroxide particles took place in the hydrophilic layers of lamellar phase I in spherulites composed of AOT (dioctyl sulfosuccinate sodium salt), because the vesicle wall is selectively permeable to the anions but practically impermeable to cations. Inorganic salts were encapsulated within the hydrophilic layers of spherulites. Indium−tin hydroxide particles were collected by breaking the spherulite structures by adding acetone after reaction, and spherical indium−tin oxide (ITO) particles of about 10−30 nm in size were obtained after calci...