The manipulation and characterization of patterned surfaces: I. Oriented nanoscale porous materials II. Drop mobility on surfaces with patterned wettability
This thesis describes research in the control over long-range order and orientation of porous nanoscale materials and liquid mobility on surfaces with patterned chemistry and topography. A variety of researches will cover the topics ranging from preparation of ordered block copolymers and anodized aluminum oxides, and dynamic wettability on chemically patterned wafers with or without topography.
The structure evolution of BCP thin films exposed with binary solvent mixture vapors at different temperatures will be investigated by scanning force microscopy and grazing incidence small angle X-ray scattering. The swollen thin films will undergo typical phase separation depending on thickness, temperature, and exposure time, which will determine the morphology of the resulting porous templates.
A new approach for preparing ordered nanoporous AAO will be demonstrated using the pattern transfer of BCP structures to the surface of aluminum. By solvent annealing the BCP films in solvent vapor, arrays of cylindrical microdomains with a high degree of lateral order will be produced. Using reactive ion etching, the template of the nanoporous film will be transferred to the Al surface and the subsequent anodization in a concentrated acid solution will generate channels with the center-to-center distance and lateral order of the BCP film.
A study of drop mobility on a surface with patterned wettability will be the final topic in the thesis. Silane chemistry, selective etching, and microcontact printing will be used to prepare designs on chemically patterned wafers with topography. The samples will have two different areas; one on which a liquid drop will move easily and another that will restrict its motion. Dynamic contact angle measurements will then be performed on the surfaces to determine the effect on drop mobility. The objective is to show that both contact angle and contact angle hysteresis are important in regards to drop mobility. The growth of condensed water droplets on these surfaces will be viewed and recorded.