Materials processing using supercritical fluids

One of the most interesting areas of supercritical fluids applications is the processing of novel materials. These new materials are designed to meet specific requirements and to make possible new applications in Pharmaceuticals design, heterogeneous catalysis, micro- and nano-particles with unique structures, special insulating materials, super capacitors and other special technical materials. Two distinct possibilities to apply supercritical fluids in processing of materials: synthesis of materials in supercritical fluid environment and/or further processing of already obtained materials with the help of supercritical fluids. By adjusting synthesis parameters the properties of supercritical fluids can be significantly altered which further results in the materials with different structures. Unique materials can be also obtained by conducting synthesis in quite specific environments like reversed micelles. This paper is mainly devoted to processing of previously synthesized materials which are further processed using supercritical fluids. Several new methods have been developed to produce micro- and nano-particles with the use of supercritical fluids. The following methods: rapid expansion of supercritical solutions (RESS) supercritical anti-solvent (SAS), materials synthesis under supercritical conditions and encapsulation and coating using supercritical fluids were recently developed. Jedna od najinteresantnijih oblasti primene natkriticnih fluida je procesiranje novih tipova cvrstih materijala. Zahvaljujuci svojim specificnim karakteristikama, natkriticni fluidi se mogu iskoristiti za dobijanje novih materijala sa osobinama znatno drugacijim nego kod konvencionalno dobijenih materijala. Ovi novi materijali su dizajnirani da zadovolje specificne zahteve i da omoguce nove primene u sledecim oblastima: farmaceutske hemikalije, heterogena kataliza, mikro i nano cestice za specijalne primene novi izolacioni materijali, superkapacitatori kao i druge tehnicke primene novih materijala. Postoje dve osnovne mogucnosti primene natkriticnih fluida u procesiranju materijala: sinteza materijala pod natkriticnim uslovima i naknadno procesiranje dobijenih materijala uz pomoc natkriticnih fluida. Neke od sinteza materijala se odvijaju pod natkriticnim uslovima kao u slucaju poletilena niske gustine. Modifikacijom procesnih parametara moguce je modifikovati karakteristike natkriticnog fluida i na taj nacin promeniti karakteristike i strukturu dobijenog materijala. Mater