Ryota WAKAI
Development of Preparation Methods for Organic Nanoparticles Based on Mist Separation
Yukiko TAKAHASHI
New preparative methods for organic nanoparticles based on mist generation and its separation in gaseous phase have been proposed with a goal of contiguous, versatile, and size selective preparation as well as stable particle dispersion. Mist atomized by an ultrasonic spray or a nebulizer is passed through a horizontal hollow tube with nitrogen stream in order to obtain similarly sized particles. Two alternative heating process of mist are performed with mist separation in gaseous phase or after mist separation with hot water to produce nanoparticles. Processes of precipitation by dissolving the mist and generation by heating the mist were considered as particle formation. In case of dissolving the mist, Particle size was evaluated in terms of the glass tube length, dye concentration. In case of heating the mist, influence of particle formation was investigated in terms of flow rate of nitrogen. Typical dyes perylene and TPP were tested to investigate the application possibility. By adding gelatin decomposition product (UDX) to the dispersion, the dispersion containing organic dye particles were kept stable at pH 9 with 1.0 g/l UDX and its zeta potential showed over |30 mV|. Dissolving the mist, in case of perylene, the concentration wasn¡Çt suggested to influence particle size. Because particles prepared in hot water were dissolved and precipitated again due to acetone that dissolved in dispersion containing particle. In case of TPP, the concentration and the effect of the glass tube length were suggested to influence particle size. By contrast, the particle size variations were estimated to be difficult to suppress. Particle prepared by using the nebulizer was smaller variations than using ultrasonic spray. Heating of the mist, particles were prepared regardless of the difference of the flow rate of nitrogen
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