Wetting and the emergent properties of complex fluids on planar colloidal crystals

Surfaces displaying periodic roughness and porosity are interesting for the study of surface free energy and supported membranes. Periodic roughness, or curvature, is known to effect lipid membranes. Surfaces presenting this scale of curvature could allow for imaging membranes with controlled imposed curvature. Furthermore, porosity of a surface enables the study of transport across a membrane. Ion transport across membranes is critical to nervous system function and still an active area of research since it involves the collective distribution of ions in the system. Also, the surface free energy of a surface is scaled by surface roughness and porosity. This is known as the lotus effect. This produces a useful result where surfaces submerged in water will stay dry.;The work contained in this thesis built a system that exhibits both porosity and periodic curvature, colloidal crystals, and then studies how both lipid vesicles and water interact with the surface as a function of surface wettability. First, a physical confinement technique was adapted to produce colloidal crystals. By controlling the wettability of one of the surfaces used to assemble the crystals, spatially defined patterns of colloidal crystals could be produced. Second, lipid vesicles were self assembled on crystals of varying colloidal size. The result is a threshold for suspending a membrane over the pores based on the ratio of vesicle size to pore size. Third, the self assembly of hydrophobic silanes on silica colloidal crystals renders the surface super hydrophobic. When submerged in water, the porous material stays dry. By spatially removing the silanes the regenerated hydrophilic silica surface can be selectively doped with aqueous moieties. Fourth, lipid membrane assembles on colloidal crystals surfaces with patterns of wettability do not show the lipid depletion at the monolayer -- bilayer junction seen on planar surfaces. This result demonstrates lipids ability to heal over defects given increases in entropy. Finally, the proton transport was measured across the suspended membrane. Proton transport matches what has been measured in vesicles using single vesicle measurements indicating that supported suspended membranes are forming good seals to the underlying aqueous environment.