Three types of spherulitic morphologies have been investigated in dual substrate mode of BelousovZhabotinsky (BZ) type reaction system. Prior to growth of spherulites, three distinct patterning behaviors have been observed sequentially during the reaction process. Initial and the early-phase of reaction showed the emergence of concentric ring-like wave patterns. A colloidal-state of reaction consists of numerous fine solid particles, which forms primarily some nucleation centers of dendritic characters. The nucleation centers were found to grow in sizes and shapes with the progress of reaction. It leads to growth of dendritic-like spherulitic crystal patterns. The resultant spherulites showed transitions in their morphologies, including sea-weeds and rhythmic spherulitic crystal patterns, by the effects substituted organic substrate and in the higher concentration of bromate-initiator respectively. The branching mechanism and crystal ordering of spherulitic textures were studied with help of optical microscope (OPM) and scanning electron microscope (SEM). Characteristics of crystal phases were also evaluated using X-ray diffraction (XRD) and differential thermal analysis (DTA). Results indicated that the compositions of reactants and crystal orderings were interrelated with morphological transitions of spherulites as illustrated and described.

The morphological orders of spherulitic crystal patterns in a Belousov-Zhabotinsky-type oscillatory reaction system were studied. The experiments showed that the morphology of crystal patterns were highly dependent on the reaction temperature. The reaction was initially carried out at 30 • C, leading to the growth of multi-centred spherulitic patterns. The single-centred spherulitic patterns with fairly large crystal fibrils were obtained at 35 • C. A number of undersized crystal assemblies with fractal geometry were also investigated at 25 • C. The gross morphology of the crystal patterns was examined using optical microscopy and a scanning electron microscope which revealed the fibrous organisations. A particle-mediated self-assembly scheme was proposed for the growth of the spherulitic patterns. The insight into the nucleation mechanism, growth behaviour, and morphological orders of the growing patterns is discussed in detail. The crystal phases, ordering of textures, and composition of the crystals were characterised by thermal and X-ray diffraction techniques.