Free-standing microcrystals of a fluorescent organic dye:: Preparation and spectroscopic study

Suspensions of microcrystals were obtained from an organic fluorescent dye, 4-n-octylamino-7-nitrobenz-2-oxa-1,3-diazole, by reprecipitation in water in the presence of various macromolecules: anionic or cationic PAMAM dendrimer, poly( acrylic acid, sodium salt), poly( acrylamide), and calf thymus DNA. The use of these additives allowed the size and shape of the microcrystals to be controlled. A study by UV/vis absorption and fluorescence spectroscopy revealed some common points, but also some interesting differences, in the optical behaviour of the five samples. Copyright (C) 2006 Mouhammad Abyan et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.