Characterization by atomic force microscopy of fused-silica capillaries chemically modified for capillary electrokinetic chromatography
Fused-silica capillary tubes with 50-microm bores have been chemically modified to yield octadecyl-derivatized surfaces with increased surface area. Alkylation is achieved in three steps: etching, silane adlayering, and olefin hydrosilation. Surface roughness, surface area, surface-tip attractive forces, and topographic images of the native, etched, silane-adlayered, and alkylated capillary bores as measured by atomic force microscopy are presented here. Significant roughening occurs during the etching process, but the most dramatic change in roughness and surface adhesion forces occurs in the hydrided (silane-adlayered) capillary surface. Topographic smoothing and passivation of surface activity are observed for the alkylated capillary surface.
Pullen
PE
Department of Chemistry, San Jose State University, California 95192, USA.
Pesek
JJ
Matyska
MT