Fabrication of aragonite rosette superstructure through the weak interaction between nonionic polymers and Ca²⁺

Abstract

ABSTRACT:The controlled formation of aragonite by simple method under ambient condition is a big challenge for biomaterial scientists. In this article, we took poly (N-vinyl pyrrolidone) (PVP) as an example to investigate the influence of water-soluble nonionic polymers on the polymorphs of CaCO 3 via CO 2 diffusion method under ambient pressure and temperature, and found that the existence of PVP molecules favors the formation of aragonite with rosette superstructure. A possible mechanism is proposed that nonionic polymers can be doped into amorphous calcium carbonate (ACC) particles and further participate in the transformation process from ACC to aragonite and then promotes the formation of rosette superstructure through parallel aggregation by crosslinking the aragonite nuclei. The experiments of CaCO 3 crystallization in presence of poly(ethylene oxide) (PEO) and poly(vinyl alcohol) (PVA) confirmed the mechanism.

Lauric acid triggered in situ surface modification and phase selectivity of calcium carbonate: its application as an oil sorbent

“…Some of the rods had multi-or Y-branched structures and were formed from small, needle-like particles that aggregated finally into sheaf or dumbbell shapes through parallel aggregation. 57 A similar morphology of aragonite has been reported earlier by Zhou et al using polymers as additives. 58 Fig.…”

Crystallization of CaCO3in Water–Alcohol Mixtures: Spherulitic Growth, Polymorph Stabilization, and Morphology Change

“…Zhou and colleagues argued that the porous structure and slight misorientation were evidence for oriented attachment where separate, individual nanoparticles spontaneously aligned themselves. In a system containing pyrrolidone, Shi et al 37 reported formation of "rosette superstructures" that they interpreted to have developed from small, needle-like particles that evolved into shuttles, rods, and finally sheaf or dumbbell shapes through parallel aggregation.…”

Controllable Synthesis of Various CaCO3 Morphologies Based on a CCUS Idea

“…Through parallel aggregation, they aggregated into highly monodisperse sheaf shapes , under the action of EDA (and/or BDO) dispersant, localized nucleation centers, or structure-directing agents (Figure A). In other words, the sheaf-like CaCO 3 microparticles were formed by mesoscale assembly of hierarchical rods . Increasing the concentration to 3.0 g/L, these small aggregated particles were first formed in the early stages of dumbbell-like formation, and then grew and transformed into irregular hexahedron subunits, which were completely driven by crystal facet selective adsorption and similar orientation attachment modes. , Ammonium ions adhered to the surfaces of subunits, which led to a lowering of surface energy and inhibition the growth of surfaces in this direction .…”