1. Crystal Whisker Growth on Porous Coatings
Lorraine F. Francis, Department of Chemical Engineering and Materials Science, University of Minnesota
The goals of this research are to elucidate the mechanism of crystal growth for needle-like KCl whiskers on the surfaces of solution saturated porous coatings, to control the whisker dimensions, and to explore the applications of the whiskers.
Year 2 Results:
Whiskers were grown on narrow lines of porous silica coating prepared by dip coating onto a hydrophilic / hydrophobic pattern created on a Si wafer.
KCl sheets were formed on pattered coatings from growth onto fallen whiskers
(3) In situ monitoring of whisker growth indicated whiskers can grow by ion addition to the base
KCl Solution
Whisker Growth Zone
Liquid Level
Front View
Side View
Porous Coating
WHISKER GROWTH ON PATTERNED COATINGS
Hydrophobic Spacing
Convection Flow
Diffusion Flow
Evaporation Flux t1 t2 t3
100um
Whiskers grown on a patterned coating
100um
Sheet
Fallen Whisker
Whisker
Porous Coating
Hydrophobic Spacing
Sequence of images showing a whisker growing from the base
Sheets grown from a fallen whisker on patterned coating