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Faster nucleation at lower pH: amorphous phase mediated nucleation kinetics.
Shuqin Jiang1, Yan Chen, Haihua Pan
1Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou 310027, China.
Physical Chemistry Chemical Physics : PCCP
|June 21, 2013
Summary
Faster hydroxyapatite nucleation at lower pH challenges existing theories. Residue calcium ions in solution are found to trigger amorphous calcium phosphate transformation, explaining nonclassical crystallization and biomineralization.
Area of Science:
- Materials Science
- Biomineralization
- Crystallization Kinetics
Background:
- Classical nucleation theory predicts slower hydroxyapatite (HAP) formation at lower pH and supersaturation.
- Understanding the mechanisms governing HAP nucleation is crucial for biomaterials and industrial applications.
Purpose of the Study:
- To investigate the nonclassical nucleation kinetics of hydroxyapatite.
- To elucidate the role of amorphous calcium phosphate (ACP) in HAP crystallization.
- To identify factors influencing HAP nucleation at low pH.
Main Methods:
- Experimental investigation of HAP nucleation under varying pH conditions.
- Analysis of amorphous calcium phosphate (ACP) phase transformation.
- Characterization of mother liquor composition and its effect on crystallization.
Main Results:
- Observed faster HAP nucleation at lower pH, contradicting classical models.
- Identified residual calcium ions in the mother liquor as the key trigger for ACP phase transformation.
- Demonstrated the critical role of ACP in nonclassical HAP crystallization.
Conclusions:
- The study reveals a novel mechanism for HAP nucleation driven by residual calcium ions.
- Findings provide a deeper understanding of nonclassical nucleation kinetics in ACP-mediated crystallization.
- The results offer insights into biomineralization processes and potential applications in materials science.
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