Fpinnovations

The University of British Columbia

Mark John Maclachlan

Wadood Yasser Hamad

Kevin Eric Shopsowitz

Hao Qi

A mesoporous metal oxide materials with a chiral organization; and a method for producing it, in the method a polymerizable metal oxide precursor is condensed inside the pores of chiral nematic mesoporous silica by the so-called 'hard templating' method. As a specific example, mesoporous titanium dioxide is formed inside of a chiral nematic silica film templated by nanocrystalline cellulose (NCC). After removing the silica template such as by dissolving the silica in concentrated aqueous base, the resulting product is a mesoporous titania with a high surface area. These mesoporous metal oxide materials with high surface area and chiral nematic structures that lead to photonic properties may be useful for photonic applications as well as enantioselective catalysis, photocatalysis, photovoltaics, UV filters, batteries, and sensors.

Chiral nematic nanocrystalline metal oxides

A composition and a method for producing mesoporous carbon materials with a chiral or achiral organization. In the method, a polymerizable inorganic monomer is reacted in the presence of nanocrystalline cellulose to give a material of inorganic solid with cellulose nanocrystallites organized in a chiral nematic organization. The cellulose can be carbonized through thermal treatment under inert atmosphere (e.g., nitrogen or argon) and the silica may subsequently be removed using aqueous solutions of sodium hydroxide (NaOH) or hydrogen fluoride (HF) to give the stable mesoporous carbon materials that retain the chiral nematic structure of the cellulose. These materials may be obtained as free-standing films with very high surface area. Through control of the reaction conditions the pore-size distribution may be varied from predominantly microporous to predominantly mesoporous materials. These are the first materials to use cellulose as both the structural template and carbon source for a mesoporous carbon material. These are also the first carbon materials to combine mesoporosity with long-range chiral ordering. Possible applications for these materials include: charge storage devices (e.g. supercapacitors and anodes for Li-ion batteries), adsorbents, gas purifiers, light-weight nanocomposite materials, catalyst supports (e.g., for chiral transformations), gas storage, and as a hard-template to generate other materials, preferably with chiral structures.

Chiral or achiral, mesoporous carbon

In this invention, we disclose a method as well as silica and/or organosilica mesoporous materials obtained by templating using nanocrystalline cellulose and removal of the latter using acidic conditions. The resultant mesoporous silica materials are characterized by having high surface area with tunable iridescence resulting from the long-range chiral nematic organization. This invention is an improvement over the formation of composite materials formed with nanocrystalline cellulose (NCC) and silica, where the calcination of the materials led to removal of the cellulose and formation of a mesoporous silica material. Characteristically, the removal of the NCC template using acidic conditions differentiates the silica materials thus obtained in two ways: (1) It does not lead to as significant contraction of the materials as from calcination thereby giving access to materials with larger mesopores; and (2) it allows the formation of mesoporous chiral nematic compositions that include heat-sensitive components. This approach may be used to prepare the first example of a mesoporous organosilica material with a chiral nematic pore structure. Examples of possible applications of this material include optical filters, adsorbents, chiral stationary phases for chromatography, sensors, composite materials, membranes, and templates for creating other chiral materials.

Process for preparation of mesoporous silica and organosilica materials

The present invention describes a composition and a method for producing mesoporous silica materials with a chiral organization. In the method, a polymerizable inorganic monomer is reacted in the presence of nanocrystalline cellulose (NCC) to give a material of inorganic solid with cellulose nanocrystallites embedded in a chiral nematic organization. The NCC can be removed to give a stable porous structure that retains the chiral organization of the NCC template. The new materials may be obtained as iridescent free-standing films with high surface area. Through control of the reaction conditions, the color of the films can be varied across the entire visible spectrum. These are the first materials to combine mesoporosity with long-range chiral ordering that leads to photonic properties. Examples of possible applications of the materials are: lightweight reinforcement materials, low k dielectric materials, tunable reflective filters, adsorbents, stationary phases for chromatography of chiral or achiral substances, supports for catalysts (e.g., for asymmetric synthetic transformations), and as a template to generate other new porous materials (e.g., porous carbon or porous metals), preferably with chiral nematic structures.

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Vancouver, Canada

Mark John Maclachlan