abstract
Vibrational spectroscopy, Si-29 and P-31 magic-angle spinning nuclear magnetic resonance spectroscopy and high resolution transmission electron microscopy were used to investigate structural aspects of SiO2-P2O5-CaO-Na2O-MgO glasses. The experimental results show that for the two compositions, 25.3SiO(2)-10.9P(2)O(5)-32.6CaO-31.2MgO and 33.6SiO(2)-6.40P(2)O(5)-19.0CaO-41.0MgO, phosphorous is present in a nano-crystalline form with interplanar distances in the 0.21-0.26 nm range. The two glasses develop a surface CaP-rich layer and the presence of any intermediate silica-rich layer was not detected. It was suggested that the phosphate nano-regions may play a key role in the initial stages of the bioactive process, acting as nucleation sites for the calcium phosphate-rich layer. (C) 2008 Elsevier B.V. All rights reserved.
keywords
IN-VITRO BIOACTIVITY; DOT 2SIO(2) SYSTEM; CERAMICS; FLUID; RAMAN
subject category
Materials Science
authors
Aguiar, H; Solla, EL; Serra, J; Gonzalez, P; Leon, B; Almeida, N; Cachinho, S; Davim, EJC; Correia, R; Oliveira, JM; Fernandes, MHV
our authors
J. Martinho Oliveira
Coordinator Professor
Maria Helena Figueira Vaz Fernandes
Retired ProfessorGroups
G4 - Renewable Materials and Circular Economy
G5 - Biomimetic, Biological and Living Materials
acknowledgements
The authors acknowledge the partial financial support of Ministerio de Educacion y Ciencia, Spain (MAT2004-02791, HP2004-0064, PGIDT05PXIC30301PN, 2006/12) and of Conselho de Reitores das Universidades Portuguesas, Portugal (Integrated Action E-75/05).