Calcite mesocrystals: a very effective block polyelectrolyte for crystal "Morphing"

Abstract

A family of calcite nanocrystal superstructures with unusual morphology were obtained from crystallization of calcite by the CO2 gas diffusion technique in the presence of a bioinspired double hydrophilic block copolymer, polyethyleneglycol-blockpoly (L-aspartic acid). From the typical calcite rhombohedra as a starting situation, the morphology can be systematically varied via various unusual porous mesocrystal morphologies to hemispheres composed of fine calcite triangles. The formation of mesocrystals is starting at a polymer concentration of only 10 -3 g/L and shows two remarkable results: (a) the reported bioinspired block copolymer is the so far most active polymer for mesocrystal formation reported to our knowledge, and (b) the data prove that nucleation promoters exist, which can form nanocrystals for mesocrystal formation even without enhanced colloidal stabilization. This gives mesocrystal formation a much broader operation range than previously assumed.

Precision Polymers—Modern Tools to Understand and Program Macromolecular Interactions

“…Figure 5, right). [54] The most surprising fact was the unexpected high potency of the additive. Already at concentration in the ppm range, efficient change of the nucleation mechanism was found, turning a ''regular'' default calcite crystal into a mesocrystal with surface roughness and developed texture.…”

“…Already at concentration in the ppm range, efficient change of the nucleation mechanism was found, turning a ''regular'' default calcite crystal into a mesocrystal with surface roughness and developed texture. [54] Depending on the polymer/mineral ratio, very specific structural features were discovered due to the multiple roles of the polymer additives involved in crystallization processes. In most cases a surprising and unexpected beauty of the as formed structures was revealed.…”

The effect of sulfated polysaccharides on the crystallization of calcite superstructures

“…The effects of polymers' additives on the crystallization kinetics and crystal morphology of CaCO 3 were also studied. For example, Colfen et al [26][27][28][29][30] studied the morphology changes of CaCO 3 crystals in the presence of block copolymers additives and it was shown that CaCO 3 crystallizes, resulting in the formation of CaCO 3 mesocrystals. The presence of carrageenan polysaccharides as additive in the crystallization of CaCO 3 and its various effects on the crystallization kinetics and crystal morphology will be discussed separately.…”

Preparation and structure evolution of bowknot-like calcium carbonate particles in the presence of poly(sodium 4-styrene sulfate)

“…Due to the interference of sulfonate group and the polymer backbone, ACC NPs are easily formed and in situ stabilized by PSS. Previously, Wang et al [49,50] have confirmed the existence of PSS-Ca 2+ complex in solution ahead of crystallization. They further demonstrated that the early nanoparticles are amorphous.…”