COLL 281 |
| Venkat R. Koganti and Stephen E. Rankin. Department of Chemical & Materials Engineering, University Of Kentucky, 177, F.Paul Anderson Tower, Lexington, KY 40508-0046 |
| When tetraethoxysilane, surfactant (Brij-56), water, acid and ethanol are combined and dip coated, we can create films with hexagonal close packed (HCP) mesopores. Other researchers who have made similar HCP thin films have found that the pores align parallel to the surface of either hydrophilic or hydrophobic substrates. Simulations predict that this is not surprising, and that perpendicular pore alignment should only be promoted by homogeneous surfaces that do not have a strong preference for either polar or nonpolar groups. We experimentally confirm this hypothesis. We prepare glass slides with variable surface chemistry by partially silylating native hydroxyl groups with trimethylchlorosilane. We present XRD and TEM results that suggest that surfaces with an optimal mixture of hydrophilic and hydrophobic groups may indeed cause the HCP mesopores in these films to align perpendicular to the substrate. Untreated and highly passivated glass surfaces both align the pores parallel to the substrate surface. |
|
Nanoscience and Nanotechnology
6:00 PM-8:00 PM, Monday, March 29, 2004 Disneyland -- North Exhibit Hall, Poster
Division of Colloid and Surface Chemistry |