Polyelectrolyte-Directed Nanoparticle Aggregation: Systematic Morphogenesis of Calcium Carbonate by Nonclassical Crystallization

Abstract

Besides the classical atom/ion/molecule based mechanism, nonclassical crystallization provides a nanoparticle-based crystallization pathway toward single crystals. However, there is a lack of experimentally established strategies for engineering a range of crystalline microstructures from common nanoparticles by nonclassical crystallization. We demonstrate that a commercial random copolymer polyelectrolyte poly(4-styrene sulfonate)-co-(maleic acid) (PSS-co-MA) considerably guides crystallization of calcium carbonate (CC) with a high versatility. The bioinspired nonclassical crystallization protocol yielded a series of calcite microstructures. Calcite single crystals obtained at low supersaturation show a pseudo-dodecahedral shape with curved faces, whereas increasing supersaturation generated calcite mesocrystals with pseudo-octahedral shapes and scalloped surfaces. Further increase of supersaturation induced the formation of polycrystalline multilayered and hollow spheres. In the initial growth stage of all these microstructures, amorphous CC nanoparticles formed as the early product. Remarkably, microparticles with minimal primitive (P)-surface were captured as the prominent intermediate indicative of liquidlike behavior. Moreover, nanogranular structures exist broadly in the as-synthesized crystals. These results demonstrate that the polyelectrolyte can effectively stabilize the amorphous CC nanoparticle precursors, impart control over the evolution from amorphous precursors via a liquid aggregate through P-surface intermediates to the final crystals, and thus allow the morphogenesis. Simple variation of calcium and polyeletrolyte concentrations enables a systematic control over the size and morphology of particles among pseudo-dodecahedra, pseudo-octahedra, multilayered spheres, and hollow spheres, which are expressed in a morphology diagram. A unifying nanoparticle aggregation formation mechanism was suggested to explain the morphogenesis by the combination of nonclassical crystallization and surface area minimization principles.

The multiple effects of amino acids on the early stages of calcium carbonate crystallization

“…6c and d). Similar morphologies have previously been obtained in the presence of different polymeric additives [14,37,[63][64][65] as well as negatively charged silicate species [66]. In some of these cases, truncation of edges and corners was ascribed to face-selective adsorption of the additives, which thus be- came stabilized and exposed.…”

A nanocomposite superstructure of metal oxides with effective charge transfer interfaces

“…The resulting precipitates are then collected and washed to remove impurities, and, in some cases, the precipitates also require further annealing. In recent years, new methods such as microwave-assisted hydrothermal 15 , bioinspired 16 and titration 17 methods have been developed to simplify the synthesis procedure and improve its efficiency. For instance, Zhou et al 6 prepared anatase TiO 2 mesocrystals by topotactically transforming NH 4 TiOF 3 crystals without changing their morphology.…”

On Mineral Retrosynthesis of a Complex Biogenic Scaffold

“…Mediated by non-classical crystallization processes, a systematic control over the size, structure and morphology of particles is achieved by applying PSS-co-MA during CaCO 3 growth [68,69]. Given the functions of sulfated macromolecules in egg shell mineralization [48], PSS-co-MA (molar mass 20,000 g/mol) is an interesting synthetic counterpart and is evaluated as an additive during retro-mineralization of the egg biomineral.…”