Hierarchically porous materials are of interest in a wide range of applications. If the materials are electronic or ionic conductors such materials are of interest as electrodes for use in fuel cells, flow batteries, electrocatalysis, and pseudo/supercapacitors. We have demonstrated the synthesis of hierarchically porous carbon, metal and metal oxide monoliths. Hierarchically porous silica with porosity at three length scales: 0.5-30 micrometer, 200-500 nm, and 3-8 nm, is used as a template to form these materials. The porosity of the silica template is produced by spinodal decomposition (0.5-30 micrometer), particle agglomeration (200-500 nm) and addition of surfactant or block copolymer (3-8 nm). Nanocasting: replication of all or part of the structure via one of a number of chemical replication techniques has been used to produce the carbon, metal oxide and metal replicas. The final surface areas of the materials can be as high as 1200 m2/g for carbon replicas, and >300 m2/g for metals and metal oxides. The use of the nanocasting technique allows for formation of materials that are compositionally or spatially heterogeneous.

We report here results on the synthesis and characterization of hierarchically porous monoliths of carbon and, nickel and the use of some of these monoliths in catalysis and electrochemical capacitors.

Hierarchically porous silica monoliths were introduced into liquid phase chromatography at the beginning of the last decade. The high surface area, high void volume and bicontinuous nature of the porosity of the materials are significant advantages over existing chromatographic supports and have resulted in rapid acceptance of these materials into the chromatography market.

We report here on the synthesis of 3-D porous silver, cobalt oxide and zinc oxide monoliths, their materials characterization, fabrication as liquid chromatographic columns and initial chromatographic characterization. The, as prepared, columns gave very low back pressure, consistent with the bicontinuous nature of the columns. Cobalt oxide and zinc oxide both demonstrated retention of a number of nitrogen heterocycles, providing the basis for molecular separation.

Two methods to create biomimetic anti-reflection nanostructures in ordinary glass microscope object slides are presented. One technique is based on a nanosphere lithography process combined with physical vapour deposition of nickel and reactive ion etching (RIE). The other uses plasma induced dewetting of a smooth nickel surface. The amount of reflected light was measured and a method to simulate the reflectivity from an atomic force microscopy (AFM) topography scan of the glass surface is presented. The reflectivity for visible light at normal incidence was reduced to 20-50 % of the original value with both methods and the simulation gives results in good agreement to the measurement.

Three dimensional silica photonic crystals with the gyroid minimal surface structure have been synthesized using the butterfly Callophrys rubi as a template. The replicas are synthesized with a high degree of fidelity, which is confirmed by the spectral and morphological characterization. Further, the material is shown to be optically active.

From wings of flies to plant leafs, hydrophobic surfaces are well-common in nature. Many of these surfaces have micro and nano hierarchical structures coated with low surface energy layer. In this work, we mimicked similar structure by fabricating Teflon coated periodic and well-ordered silver nanorod arrays and investigated the effect of nanorod separation on water contact angle (WCA). The silver nanorod arrays were deposited on patterned and flat silicon substrates using glancing angle deposition (GLAD) technique. Then a thin layer of Teflon was deposited on the silver nanorods by small angle deposition (SAD) technique. A systematic increase in water contact angle was observed with increasing nanorod separation which is attributed to the decreased area fraction of solid-liquid interface.