Supercritical reprecipitation method

Techniques such as vacuum evaporation method, melting process in a glass matrix, and so on [88], basically fundamental fabrication techniques for inorganic NPs and semiconductor quantum dots, would not be expected to be applied to organic and polymer compounds and materials because of their thermal instability [89, 90]. In contrast, the so-called reprecipitation method [1-4] is a useful and convenient procedure to prepare organic and polymer NCs. This method has been further improved as the supercritical reprecipitation method [1-3,28,29], reprecipitation-microwave irradiation method [1-3, 30-34], and inverse-reprecipitation method [1-3, 27, 42, 43], being closely related to the physicochemical properties of the target compound and materials. 

In addition, the supercritical reprecipitation method [1-3, 28, 29] is available for sparingly soluble compounds in a water-miscible organic solvent, e.g., titanyl-phthalocyanine and fullerene. After dissolving titanyl-phthalocyanine in supercritical acetone fluid, this fluid was cooled by a mixture of acetone and water at room temperature to nanocrystallize titanyl-phthalocyanine. We could control successfully the crystal size and forms of titanyl-phthalocyanine NCs by changing the temperature of supercritical acetone and the volume ratio of the mixed refrigerant of acetone with water. In particular, the y-form of titanyl-phthalocyanine NCs obtained is noted in the industrial field of Xerography [94]. 

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See also in sourсe #XX -- [ ]

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