Solid-liquid adsorption of calcium phosphate on TiO{sub 2}
Calcium phosphate (CP) in aqueous solution was exposed to thin-film TiO{sub 2} surfaces at predetermined times ranging from 10 min to 20 h using a liquid reaction apparatus (LRA). Surface analysis was then performed using X-ray photoelectron (XPS) and Auger electron (AES) spectroscopies and time-of-flight secondary ion mass spectromemtry (ToF-SIMS) with polyatomic primary ions. XPS revealed that CP nucleated and grew on the TiO{sub 2} surface, with phosphate groups growing on top of an initial 2-dimensional (2D) Ca-rich layer. AES depth profiling of a 4-h solution exposure complemented this finding and gave additional evidence for 3-dimensional (3D) phosphate islands forming on top of the calcium. ToF-SIMS analysis of CP adsorbed on the surface indicated that the predominant phase on the surface was brushite, CaHPO{sub 4}{sm{underscore}bullet}2H{sub 2}O. A model for Ca{sup 2+} cation bridging at the oxide interface is proposed.
- Research Organization:
- Texas A and M Univ., College Station, TX (US)
- Sponsoring Organization:
- USDOE; National Science Foundation (NSF)
- OSTI ID:
- 20013614
- Journal Information:
- Langmuir, Vol. 15, Issue 21; Other Information: PBD: 12 Oct 1999; ISSN 0743-7463
- Country of Publication:
- United States
- Language:
- English
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