Abstract:
Thin films for use as dielectric in semiconductor and other devices are prepared from silica zeolites, preferably pure silica zeolites such as pure-silica MFI. The films have low k values, generally below about 2.7, ranging downwards to k values below 2.2. The films have relatively uniform pore distribution, good mechanical strength and adhesion, are relatively little affected by moisture, and are thermally stable. The films may be produced from a starting zeolite synthesis or precursor composition containing a silica source and an organic zeolite structure-directing agent such as a quaternary ammonium hydroxide. In one process the films are produced from the synthesis composition by in-situ crystallization on a substrate. In another process, the films are produced by spin-coating, either through production of a suspension of zeolite crystals followed by redispersion or by using an excess of the alkanol produced in preparing the synthesis composition. Zeolite films having patterned surfaces may also be produced.
Abstract:
Oxygen reduction catalysts for fuel cells are provided. The catalyst can be based on platinum-coated palladium nanotubes, or multiple twinned, crystalline silver nanowires. Also provided is a method of removing carbon dioxide using a membrane having basic functional groups, and a method of water electrolysis using a membrane having basic functional groups.
Abstract:
A hydrophilic coating can be optionally corrosion resistant and/or microbial resistant for a substrate such as a heat exchanger. The coating is provided by a zeolite layer that can be formed from a synthesis solution comprising a structure directing agent, a base, a silicon source, an aluminum source, and a solvent. In one preferred embodiment, the synthesis solution comprises tetrapropylammonium hydroxide, sodium hydroxide, aluminum oxide, tetraethylorthosilicate, and water. The layer is characterized by a zeolite MFI structure and by a composition having the formula of Mn/m[AlnSi(96−n)O192], or [AlnSi(96−n)O192]·4[(CH3CH2CH2)4N—OH] wherein M is a metal ion of valence m+ (e.g., Na+) and 27>n>=0. After formation of the coating, the organic structure directing agent can be left intact inside the zeolite coating to make the coating corrosion resistant. Alternatively, and after removal of the organic structure directing agent, a biocidal metal ion can be incorporated into the coating by an ion exchange process to render the coating microbial resistant. A hydrophilic coating that is also corrosion resistant and microbial resistant can be made by a zeolite coating with two sub-layers—the bottom sub-layer being corrosion resistant and the top sub-layer being microbial resistant.
Abstract:
A family of functionalized polymers is provided capable of forming membranes having exceptional OH− ionic conductivity as well as advantageous mechanical properties, which may be applied to membranes including such polymers for use in, e.g., AEMFC/HEMFC fuel cells. Preferred functional groups include a quaternary phosphonium, and the polymer may specifically be (tris(2,4,6-trimethoxyphenyl) phosphine)3 functionalized phosphonium polysulfone hydroxide, ECL-PVBC-QPOH, or QPOH based on any of the commercial polumers including polycarbonate (PC), poly(2,6-dimethyl-1,4-phenylene oxide) (PPO), polyetherimine (PEI), poly(ether sulfone) (PES), poly(phenylene sulfoxide) PPS, poly(ether ether ketone) (PEEK), or polybenzimidazole (PBI), polyvinyl chloride (PVC). An ionomer membrane may include polysulfone based TPQPOH, ECL-PVBC-QPOH, and/or PPO.
Abstract:
The disclosure provides biocompatible metal compositions, methods of making such compositions and uses thereof, including a method of synthesizing zeolite coatings. The disclosure further provides the zeolite-hydroxyapatite composite coatings and methods of making them, which includes forming a base zeolite layer, forming a hydroxyapatite layer on the base zeolite layer, and interlocking the hydroxyapatite layer with an outer zeolite layer. The composite can be formed on a metal substrate for bioimplants, such as titanium alloy and/or stainless steel, which is used for bioimplants.
Abstract:
A method of silylating porous silica films comprises: preparing a porous silica film; and grafting the film with a hydrophobic functional group while annealing the film. The porous silica film is a sol-gel silica film, a mesoporous silica film, in situ crystallized polycrystalline pure-silica zeolite (PSZ), spin-on PSZ, and spin-on PSZ MEL (or PSZ MEL-structural type) films. The hydrophobic functional group is trimethylchlorosilane (TMCS); dimethyldichlorosilane; methyltrichlorosilane; alkylchlorosilanes, such as (CH3(CH2)n)xSiCl4-x, where x is 1, 2, or 3; alkoxychlorosilanes; hexamethyldisilazane (HMDS), and/or aminosilanes. In addition, the steps of grafting and annealing the film are performed simultaneously, which imparts hydrofluoric acid resistance and reduces moisture adsorption to the film.
Abstract:
A method for producing zeolite films or membranes at essentially ambient pressure, which includes preparing a synthesis mixture comprising an ionic liquid solvent and an aluminum and/or silicon and/or phosphate source and converting the synthesis mixture to form a continuous zeolite layer. In addition, a method of synthesizing zeolite nanocrystals, which includes preparing a synthesis mixture, the synthesis mixture having a silica or a silica and alumina source, and a template; and synthesizing the synthesis mixture to form zeolite nanocrystals.
Abstract:
A hydrophilic coating can be optionally corrosion resistant and/or microbial resistant for a substrate such as a heat exchanger. The coating is provided by a zeolite layer that can be formed from a synthesis solution comprising a structure directing agent, a base, a silicon source, an aluminum source, and a solvent. In one preferred embodiment, the synthesis solution comprises tetrapropylammonium hydroxide, sodium hydroxide, aluminum oxide, tetraethylorthosilicate, and water. The layer is characterized by a zeolite MFI structure and by a composition having the formula of Mn/m[AlnSi(96-n)O192], or [AlnSi(96-n)O192].4[(CH3CH2CH2)4N—OH] wherein M is a metal ion of valence m+ (e.g., Na+) and 27>n>=0. After formation of the coating, the organic structure directing agent can be left intact inside the zeolite coating to make the coating corrosion resistant. Alternatively, and after removal of the organic structure directing agent, a biocidal metal ion can be incorporated into the coating by an ion exchange process to render the coating microbial resistant. A hydrophilic coating that is also corrosion resistant and microbial resistant can be made by a zeolite coating with two sub-layers—the bottom sub-layer being corrosion resistant and the top sub-layer being microbial resistant.
Abstract:
Thin films for use as dielectric in semiconductor and other devices are prepared from silica zeolites, preferably pure silica zeolites such as pure-silica MFI. The films have low k values, generally below about 2.7, ranging downwards to k values below 2.2. The films have relatively uniform pore distribution, good mechanical strength and adhesion, are relatively little affected by moisture, and are thermally stable. The films may be produced from a starting zeolite synthesis or precursor composition containing a silica source and an organic zeolite structure-directing agent such as a quaternary ammonium hydroxide. In one process the films are produced from the synthesis composition by in-situ crystallization on a substrate. In another process, the films are produced by spin-coating, either through production of a suspension of zeolite crystals followed by redispersion or by using an excess of the alkanol produced in preparing the synthesis composition. Zeolite films having patterned surfaces may also be produced.