The Surface Geometry of Vycor

✍ Scribed by A.Ch. Mitropoulos; P.K. Makri; N.K. Kanellopoulos; U. Keiderling; A. Wiedenmann

• Publisher: Elsevier Science
• Year: 1997
• Tongue: English
• Weight: 76 KB
• Volume: 193
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1997.5033

✦ Synopsis

The interface geometry of Vycor porous glass was examined by adsorption of water in conjunction with small-angle scatterwhere a is a constant and Q is the scattering vector. ing of X rays and neutrons. When the sample is dry, a fractal

The X-ray result indicates that the surface geometry of dry Vycor surface with a fractal dimension D Ç 2.5 was detected. When undergoes a change upon H 2 O saturation of the mesopore structure. wet, a soft hydrogel is formed, resulting in a diffuse boundary. When a small background correction b was allowed, D was estimated to 2.4 and 2 for the dry and the H 2 O-saturated samples, respectively

To observe a fractal surface, thorough drying of the sample is ( see also Table 1 ) . By changing the fitting parameters a and b, D was necessary, however. It was shown that a small amount of water, recalculated almost equal to the previous case. On the basis of SANS 3% w / w, is sufficient to render the surface smooth. ᭧ 1997 data, Benham et al. ( 5 ) reported that power-law exponents differ mark-

Academic Press

edly between dry and water-saturated samples with identical scattering