Zhilian Zhou

The Patterning of Sub-500 nm Inorganic Oxide Structures†

Elastomeric perfluoropolyether molds are applied to pattern arrays of sub-500 nm inorganic oxide features. This versatile soft-lithography technique can be used to pattern a wide range of materials; in this work inorganic oxides including TiO2 , SnO2 , ZnO, ITO, and BaTiO3 are patterned on a variety of substrates with different aspect ratios. An example of TiO2 posts is shown in the figure.

Low-cost PRINT manufacturing of patterned films with nano-precision

Precision patterned optical films are key components of todays display technologies, serving as brightness enhancement films, diffuser films and patterned light guides, to name a few. In recent years, much attention has been given to methodologies for patterning optical films with nanoscale precision at the scale and economics required by the Flat Panel Display industry. With this work, we report a platform technology, Pattern Replication In Non-Wetting Templates (PRINT®), for polymer-tool based manufacturing of patterned optical films for the display industry. By using Fluorocur® mold materials, the PRINT® (Pattern Replication In Nonwetting Template) technology enables low cost manufacturing of precise micro and nanoscale features with single nanometer precision from virtually any material.

Molded, High Surface Area Polymer Electrolyte Membranes from Cured Liquid Precursors [J. Am. Chem. Soc. 2006, 128, 12963−12972].

Polymer electrolyte membranes (PEMs) for fuel cells have been synthesized from easily processable, 100% curable, low molecular weight reactive liquid precursors that are photochemically cured into highly proton conductive solid membranes. The liquid precursors were directly cured into membranes of desired dimensions without the need for further processing steps such as melt extrusion or solvent casting. By employing chemical cross-linking, high proton conductivities can be achieved through the incorporation of significant levels of acidic groups without rendering the material water-soluble, which plagues commonly used non-cross-linked polymers. Fabrication of membrane electrode assemblies (MEAs) from these PEMs resulted in fuel cells that outperformed those based on commercial materials. Moreover, these liquid precursors enabled the formation of three-dimensional, patterned PEMs with high fidelity, micron-scale features by using soft lithographic/micromolding techniques. The patterned membranes provided a larger interfacial area between the membrane and catalyst layer than standard flat PEMs. MEAs composed of the patterned membranes demonstrated higher power densities over that of flat ones without an increase in the macroscopic area of the fuel cells. This can potentially miniaturize fuel cells and promote their application in portable devices.