Research Centre Germany
There is an interest in extra small transparent pigments for achieving special effects and coloration for textiles, paper,
cosmetics and plastic materials. Fluorescent silica nanoparticles has attracted great interests because of their distinctive
properties and potential applications in biological and analytical fields (e.g., in microscopy), in sensor, in optical
computing or information technology, or as markers in safety areas (makers for bank notes or passports).
Compared with other materials, silica nanoparticles possess several advantages – simple method of preparation, easy route of surface
modification and functionalization, nontoxicity and stability etc. – which makes dye-doped silica nanoparticles show great
promise in various applications. Here, we attempted to valuate the potential of such nanoparticulate dyed pigments for
coloration.
Monodispersed silica nanoparticles are prepared by Stöber and microemulsion procedure. Organic and inorganic
dyestuffs can be encapsulated into silica matrix by physical adsorption or chemical binding. In order to chemically bind
organic dyestuffs into inorganic silica matrix, the dye molecules have to be modified first by suitable silanes depends on
which kind of functional groups they have. The covalent attachment enables to enlarge the incorporated amount of
organic ingredients, reduces dye leaching problems, and in some cases, leads to stabilizing effects. The silica particles
doped by photochromic dyestuffs show color change effects. In addition, nanoparticulate noble metals are also
embedded as chromophore into silica matrix taking advantage of the strong surface plasma band. The size and
composition of the particles can be controlled precisely. Further modification and functionalization of these particles can
also be performed for special applications. Primary research of applying these particles on textiles has been done.
