Thermodynamics of Calcite Growth: Baseline for Understanding Biomineral Formation

Abstract

The complexity of biomineralized structures suggests the potential of organic constituents for controlling energetic factors during crystal synthesis. Atomic force microscopy was used to investigate the thermodynamic controls on carbonate growth and to measure the dependence of step speed on step length and the dependence of critical step length on supersaturation in precisely controlled solutions. These data were used to test the classic Gibbs-Thomson relationship and provided the step edge free energies and free energy barriers to one-dimension nucleation for calcite. Addition of aspartic acid, a common component in biomineralizing systems, dramatically affected growth morphology and altered the magnitude of the surface energy.

Growth modification of seeded calcite using carboxylic acids: Atomistic simulations

“…One way to gain this level of control is the use of growth modifying additives during the precipitation of calcite from the aqueous phase. It has been shown in the past that the adsorption of many types of polymers such as hydrophilic block copolymers [6,7], polycarboxylic acids [8][9][10][11], phosphonates [12,13] and polyamino acids [14][15][16][17] during precipitation or dissolution can modify calcite particle size and morphology. It was also shown that polycarboxylic acids can promote a very particular growth mechanisms [18], during which agglomeration of small primary particles results in a very high overall specific surface area.…”

The Use of Scanning Probe Microscopy to Investigate Crystal-Fluid Interfaces

“…There are many exceptions to this form including variations as a function of step length [30,31], variation due to low kink density [20,21], variation due to multiple kink types [32], and variation due to impurity interactions. (This last topic is covered in the chapter by J. J.…”

Spiral Growth and Step Edge Barriers

“…This mechanism was conjectured by Frank in 1949 to account for the enormous discrepancy between experimentally observed crystal growth rates and the predictions of two-dimensional nucleation theory by allowing for growth even at very low supersaturations, where nucleation is extremely unlikely [1,2]. Since then, spiral mounds have been recognized as a ubiquitous feature of many growth systems ranging from high temperature superconductors [3] to biominerals [4] and organic thin films [5,6].…”