Accession Number:

ADA551376

Title:

Superomniphobic Surfaces for Military Applications: Nano- and Micro-Fabrication Methods. Chapter 1: Lithographic Fabrication of Surfaces with Different Microgeometries and Investigation of Their Wetting Behaviour

Descriptive Note:

Technical rept.

Corporate Author:

ALBERTA UNIV EDMONTON DEPT OF MECHANICAL ENGINEERING

Personal Author(s):

Report Date:

2011-01-01

Pagination or Media Count:

64.0

Abstract:

Recent rapid improvements of micronanofabrication techniques have allowed us to prepare patterned surfaces with controlled topographic structures. In this report, three kinds of patterned surfaces, i.e., square, triangle and circle post array surfaces, have been prepared on silicon wafers. On such surfaces, for the same roughness or solid-liquid contact fraction value, different surface textures can exhibit completely different wetting behaviour. Effects of various microgeometrical parameters, such as length scale effect, edgecorner pinning effect, geometrical shape effect, direction-dependent effect, etc., on wetting have been investigated. For the patterned surfaces with fixed solid area fraction, a smaller microgeometrical length scale can induce a smaller advancing contact angle and a larger receding contact angle, when it is compared to a larger microgeometrical length scale. Competing factors such as solid area fraction and solid linear fraction are found to be responsible for such effect. Moreover, it is also revealed that there is a strong dependence of directions for surface wettability on the patterned surfaces. Different edgecorner pinning effects, including the pinning length and pinning point density, in various directions are suggested to be taken into consideration for affecting the surface wetting behaviour.

Subject Categories:

  • Physical Chemistry
  • Manufacturing and Industrial Engineering and Control of Production Systems
  • Mechanics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE