Effect of poly(vinylpyrrolidone) on transformation of the dispersed phase and gelation in a lyophobic colloid system

Transformation of the dispersed phase and subsequent gelation in an aqueous colloidal dispersion of an organic compound upon aging of the dispersion are analyzed using cryotransfer transmission electron microscopy, video-enhanced optical microscopy, and FT-Raman spectroscopy. After a few hours at room temperature, the original particles of the dispersion (prepared using only an anionic surfactant as the wetting agent) gradually disappear and are replaced by a new set of particles that are strongly anisodiametric. Entanglement of these strongly anisodiametric fibrillar units results in the formation of a network and gelation