Habit Changes of Sodium Bromate Crystals Grown from Gel Media

Abstract

Agarose, gelatin, and silica gel media have been surveyed as appropriate matrixes for the crystal growth of sodium bromate (NaBrO3). From pure aqueous solution, NaBrO3 crystallizes with a characteristic tetrahedral habit. We have demonstrated that a greater variety of habits (e.g., cubic, tetrahedral, polyhedral, and dendritic) can be reliably obtained from the growth in these gel media by controlling the solute concentration and the gel density. Agarose and silica matrixes suppress the nucleation as the gel density increases, while increasing gelatin concentrations seem to enhance crystal nucleation rates. These observations support the general hypothesis that the gel media influences the relative growth rates by controlling the solute nucleation and diffusion; however, little can be concluded about the possible chemical interaction between the polymeric backbone and the solute.

Crystal Growth of Calcium Carbonate in Hydrogels as a Model of Biomineralization

“…In addition to “generic” effects of gels on growth, specific (chemical) interactions between crystal‐gel pairs have been suggested by many studies. For example, growth in agarose gels has been used to control the enantiomeric selectivity of sodium chlorate,142 and the crystal morphology of multiple inorganic salts has also been shown to vary strongly as a function of gel type 4, 143–146. Finally, incorporation of the gel media into the growing crystals is known,58, 123, 147–149 and may depend on both chemical and physical factors, as described further in Section 4.3.…”

Growth of calcium carbonate in polyacrylamide hydrogel: Investigation of the influence of polymer content

“…For lead sulphide [43,44], sodium bromate [45] and ammonium chloride [46] grown in gels, a dendritic morphology was observed. Oaki and Imai [46] describe a dependence of the morphology from the solids content of the gel medium.…”

Synthetic polymer/single‐crystal composite

“…This figure is available in colour online at wileyonlinelibrary.com/journal/pat by Nickl and Henisch to be incorporated into calcite crystals. [32] Later, polymer (agarose and poly-acrylamide) gel networks were also found incorporated inside several protein crystals, [27,28,57] calcite, [34,58,69] sodium bromated, [59] glycine, [29] and calcium tartrate tetrahydrate. [29] In the crystal-gel pair of calcite-agarose, the distribution state of the agarose inside the calcite single-crystals were well characterized ( Fig.…”

“…Experimental observations partly confirm the expectation in the sense that agarose (a polysaccharide) that forms mechanically strong gels [63][64][65] has been found to be incorporated inside varied crystals. [28,29,33,34,[58][59][60] In addition to the mechanical properties of the gels, crystal growth rate that was demonstrated to affect the particle incorporation greatly [47][48][49][50][51] has recently been shown as another important factor for gel incorporation. [60,66] Similarly, fast crystallization was demonstrated to favor gel incorporation in the case of calcite crystallization in agarose gels.…”