A sensor system that detects a current representative of a compound in a liquid mixture features a two-electrode strip adapted for releasable attachment to signal readout circuitry. The strip comprises an elongated support (preferably flat) adapted for releasable attachment to the readout circuitry; a first conductor and a second conductor each extend along the support and comprise means for connection to the circuitry. An active electrode, positioned to contact the liquid mixture and the first conductor, comprises a single layer deposit of an enzyme capable of catalyzing a reaction involving the compound, a conductive material, and an electron mediator, capable of transferring electrons between the enzyme-catalyzed reaction and the first conductor. A reference electrode is positioned to contact the mixture and the second conductor. The system includes circuitry adapted to provide an electrical signal representative of the current. The two-electrode strip is manufactured, e.g., by screen printing, an admixture of an enzyme a conductive material, and a mediator as a single layer onto the substrate.

Strip electrode with screen printing

Disclosed are improved polymer materials. Also disclosed are fine fiber materials that can be made from the improved polymeric materials in the form of microfiber and nanofiber structures. The microfiber and nanofiber structures can be used in a variety of useful applications including the formation of filter materials.

Polymer, polymer microfiber, polymer nanofiber and applications including filter structures

A flat-panel liquid crystal display (10). The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements. The driver circuitry activates the liquid crystal domains with various drive schemes which have any number of different phases (300, 312, 318, and 320) to attain various addressing sequence times. At the end of each drive scheme, the texture of the liquid crystal material is allowed to provide either focal conic or twisted planar end states (320) across the two-dimensional array of picture elements. Each drive scheme employs at least a preparation phase (300) and a selection phase (318) to predispose the liquid crystal material to one of the end states.

Dynamic drive methods and apparatus for a bistable liquid crystal display

Described are fluorochemical surfactants derived from nonafluorobutanesulfonyl fluoride that contain polyalkyleneoxy side chains and may be copolymerized with acrylic acid or methacrylic acid to form polyacrylates or polymethacrylates. The surfactants surprisingly lower the surface tension of water and other liquids in the same or similar low values achieved by premier surfactants such as those derived from perfluorooctane sulfonyl fluoride.

Fluorochemical sulfonamide surfactants

Thermoplastic bicomponent binder fiber can be combined with other media, fibers and other filtration components to form a thermally bonded filtration media. The filtration media can be used in filter units. Such filter units can be placed in the stream of a mobile fluid and can remove a particular load from the mobile stream. The unique combination of media fiber, bicomponent binder fiber and other filtration additives and components provide a filtration media having unique properties in filtration applications.

Filter medium and structure

Fluorocarbon acrylate and methacrylate esters and polymers

Fluorocarbonsulfonamidoalkanols and sulfates thereof

Perfluoro amine compounds and quaternary derivatives

The invention includes a polymer of a vinyl or allyl fluorocarbon ester of the formula: Rf.SO2.N(R1)R.COOCH=CH2 or Rf.SO2.N(R1)R.COOCH2CH=CH2 where Rf is a perfluoroalkyl group of 4 to 12 carbon atoms, R1 is hydrogen or an alkyl group of 1 to 6 carbon atoms and R is an alkylene bridging group of 1 to 12 carbon atoms. The vinyl and allyl esters may be bulk, solution, e.g. toluene, or emulsion polymerized using peroxide catalysts, e.g. acetyl or benzoyl peroxides, either alone or together or with other ethylenic monomers such as maleic anhydride, acrylonitrile, vinyl chloride, vinyl acetate, vinyl silicones, styrene, methyl acrylate, methyl methacrylate, ethylene, isoprene and butadiene. The polymer may be modified by the use of plasticizers, carbon black, zinc oxide or by copolymerization with polyfunctional compounds which cause cross-linking. Examples describe the polymerization of N-ethyl- and N-methyl- N-perfluoro-octanesulphonyl glycine vinyl ester and the copolymeriation of N-methyl-N-perfluoro-octanesulphonyl-11-amino-undecanoic acid allyl ester and maleic anhydride. Specifications 758,467 and 857,335 are referred to.ALSO:The invention comprises vinyl and allyl esters of a perfluoroalkanesulphonamido alkylene-monocarboxylic acid having the formula: Rf SO2 N(R1)R-COOCH=CH2 or RfSO2N(R1)R-COOCH2-CH=CH2 where Rf is a perfluoroalkyl group containing 4 to 12 carbon atoms, R is an alkylene bridging group containing 1 to 12 carbon atoms and R1 is hydrogen or an alkyl group containing 1 to 6 carbon atoms. They may be prepared by esterifying the corresponding acid or prepared directly by condensing an alkali metal salt of a perfluoroalkylsulphonamide with a vinyl or alkyl ester of an omega halogenated carboxylic acid. These esters may be polymerised or copolymerised with other ethylenic compounds (see Group IV(a)) to yield a polymer that, when coated on the surface of an article, gives both a water and oil repellent surface. The monomeric esters may be used in a similar manner. In Examples (1) the sodium salt of N-ethyl-perfluoro-octanesulphonamide is condensed with vinyl chloroacetate. (2) the N-methylcompound is similarly used. (3) N-methyl-N-perfluoro-octanesulphonyl-11-amino-undecanoic acid is esterified with vinyl acetate in the presence of sulphuric acid and mercuric acetate. (4) N-perfluoro-octanesulphonyl glycine is esterified with allyl alcohol in the presence of betanaphthalene sulphonic acid. (5) N-methyl-N-perfluoro-octanesulphonyl - 11 - amino - undecanoic acid is similarly esterified. Specifications 758,467 and 857,335 are referred to.

Fluorocarbon vinyl-type esters and polymers

A composition for use in thermally-addressable liquid crystal display devices, comprising a smectic liquid crystal material and a helichromic compound possessing both a chromophoric moiety and an optically-active moiety. The helichromic compound is a circularly dichroic dye capable of propagating incident visible light in a circularly polarized manner so that all polarizations of the incident light are absorbed. The composition comprising the helichromic compound can be utilized in thermally-addressable liquid crystal display devices to provide a display which operates at lower voltages, with faster response times, and higher contrast ratios.

Harvey A Brown

Papers

Fluorocarbon acrylate and methacrylate esters and polymers

Fluorocarbonsulfonamidoalkanols and sulfates thereof

Perfluoro amine compounds and quaternary derivatives

Fluorocarbon vinyl-type esters and polymers

Helichromic-smectic liquid crystal compositions and display cells