Capillary stress in microporous thin films
- Sandia National Labs., Albuquerque, NM (United States)
- Sandia National Labs., Albuquerque, NM (United States). Ceramic Processing Science Dept.
- Univ. of New Mexico, Albuquerque, NM (United States). Center for Micro Engineered Ceramics
Development of capillary stress in porous xerogels, although ubiquitous, has not been systematically studied. The authors have used the beam bending technique to measure stress isotherms of microporous thin films prepared by a sol-gel route. The thin films were prepared on deformable silicon substrates which were then placed in a vacuum system. The automated measurement was carried out by monitoring the deflection of a laser reflected off the substrate while changing the overlying relative pressure of various solvents. The magnitude of the macroscopic bending stress was found to reach a value of 180 MPa at a relative pressure of methanol, P/Po = 0.001. The observed stress is determined by the pore size distribution and is an order of magnitude smaller in mesoporous thin films. Density Functional Theory (DFT) indicates that for the microporous materials, the stress at saturation is compressive and drops as the relative pressure is reduced.
- Research Organization:
- Sandia National Labs., Albuquerque, NM (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States); National Science Foundation, Washington, DC (United States); New Mexico Univ., Albuquerque, NM (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 244630
- Report Number(s):
- SAND--96-1280C; CONF-960401--38; ON: DE96010544
- Country of Publication:
- United States
- Language:
- English
Similar Records
Sol-gel processing of controlled porosity silica films: From aerogels to molecular sieves
Microporous and macroporous materials