Artigo
Modifications in the correlation function in poly(vinyl alcohol)/silica hybrid wet gels
Fecha
2009-02-01Registro en:
Journal of Applied Crystallography. Malden: Wiley-blackwell Publishing, Inc, v. 42, p. 10-14, 2009.
0021-8898
10.1107/S0021889808034900
WOS:000262386900002
3538107401166553
5890636096105376
Autor
Universidade Estadual Paulista (Unesp)
Resumen
Small-angle X-ray scattering was used to study structural modifications in tetraethoxysilane-derived poly(vinyl alcohol) (PVA)/silica hybrids. The basic structure of the wet gels can be described as a mass-fractal structure with fractal dimension D equal to 2 and characteristic length xi, which increases with addition of PVA. Wet gels with high PVA content exhibit a positive deviation from the mass- fractal power-law scattering at low q; this deviation is associated with additional scattering due to a second large correlation distance zeta, reinforced by the addition of PVA. The fraction of both contributions to the total correlation function was estimated; this is the first time that such a study has been carried out for mass- fractal structures.