Abstract: The invention relates to a composition comprising between 30 and 95% by volume of aerogel particles and at least one aqueous binder, where the particle diameter of the aerogel particles is less than 0.5 mm and the aerogel particles preferably have hydrophobic surface groups, a process for the preparation thereof, and the use thereof.

Abstract: To produce a composite membrane, the solution of a polymer in a volatile organic solvent is spread on water, the solvent is allowed to evaporate, the polymer is crosslinked and the polymer film formed is transferred to a porous support membrane. The polymer is preferably a polysiloxane which is cross-linked via polymer-bonded OH groups. The composite membrane is suitable, inter alia, for pervaporation.

Abstract: Compounds of the formula I ##STR1## in which R is a C.sub.1 - to C.sub.22 -alkyl radical,A.sup.1 and A.sup.2 are hydrogen or methyl or,A.sup.1 is hydrogen and A.sup.2 is the nitro group, andB is the cyano group, the nitro group or an electron-attracting organic group having a double bond which is in conjugation with the thieno?3,2-b!thiophene ring system,have a high dipole moment and a high polarizability and are suitable for purposes of nonlinear optics. If R in the formula I is a C.sub.12 - to C.sub.22 -alkyl radical, monomolecular layers can be applied to a substrate by the Langmuir-Blodgett method. The resulting layer elements are suitable, inter alia, as waveguides.

Abstract: A composite membrane comprises a porous carrier membrane (A) and a fluorine-containing permselective layer (C) which is a copolymer and has a thickness of 10 to 500 nm. The copolymer of layer (C) comprisesa) 10 to 80 mol % of monomer units of a vinyl ester of the formula (I) ##STR1## in which R.sup.1, R.sup.2 and R.sup.3 are hydrogen, alkyl radicals, cycloalkyl radicals or aryl radicals, and these radicals together have at least 5 and not more than 30 carbon atoms,b1) 5 to 50 mol % of monomer units of a vinyl alcohol of the formula (II) ##STR2## in which R.sup.4 is the hydroxyl group and up to 10% of the groups R.sup.4 can be replaced by radicals of the formula OCOR.sup.5, in which R.sup.5 is methyl, ethyl or propyl, orb2) 5 to 50 mol % of monomer units of the formula (III) ##STR3## in which R.sup.

Abstract: An optical component comprises an electromagnetic radiation-transparent polymeric medium having a second-order susceptibility of at least 10.sup.-9 electrostatic units where this polymeric medium comprises compounds having polar-aligned noncentrosymmetric molecular dipoles which have as structural element an electron acceptor which is bound to an electron donor via a conjugated .pi.-electron system, which makes possible an oscillation of the molecular dipole between a ground state having a first dipole moment and an electronically excited state having a second dipole moment different from the first, and the nonionic polymeric medium comprises an alternating arrangement of at least one Langmuir-Blodgett film each of at least two different nonionic polymers having nonlinear optical properties. Besides high mechanical and chemical stability the optical component of the invention has excellent nonlinear optical properties, for example frequency-doubling.

Abstract: A transparent molded article for optical applications made from silicon nitride and a coating thereon of oxidic silicon nitride formed by chemical reaction of the silicon nitride with oxygen. The moldings can be shaped, depending on the area of application, to give various articles, for example optical waveguides, prisms, sensor elements or lenses, and are used in all areas where high optical demands are made.

Abstract: Substituted thieno[3,2-b]thiophenes, processes for their preparation and their useCompounds of the formula I ##STR1## in which R is a C.sub.1 - to C.sub.22 -alkyl radical,A.sup.1 and A.sup.2 are hydrogen or methyl orA.sup.1 is hydrogen and A.sup.2 is the nitro group, andB is the cyano group, the nitro group or an electron-attracting organic group having a double bond which is in conjugation with the thieno[3,2-b]thiophene ring system,have a high dipole moment and a high polarizability and are suitable for purposes of nonlinear optics. If R in the formula I is a C.sub.12 - to C.sub.22 -alkyl radical, monomolecular layers can be applied to a substrate by the Langmuir-Blodgett method. The resulting layer elements are suitable, inter alia, as waveguides.

Abstract: In order to continuously produce an ultrathin, ordered layer of amphiphilic molecules on the surface of a polar liquid a directed flow of the polar liquid is produced in a duct which contains the amphiphilic molecules in dissolved or undissolved form on the surface in spread form. In the duct, a duct section having a relatively high flow rate on the surface and comprising a ramp which is arranged at the bottom of the duct and washed over by the polar liquid is provided. This is followed by a duct section having a relatively low flow rate on the surface, in which the flow is dammed up at an obstacle at a liquid level constant with time, so that an ultrathin, ordered layer of amphiphilic molecules is continuously formed in these duct sections at the polar liquid/air interface by compression of the flow. The washed over ramp is movable.

Abstract: A layer element comprises a plurality of monomolecular layers in a regular and alternating arrangement ABABAB . . . on a substrate, wherein A is a layer of a dye whose chromophore has a donor-acceptor structure and B is a layer of cellulose whose hydroxyl groups are at least partly substituted by the radical ##STR1## where R.sup.1 and R.sup.2 are each independently of the other an alkyl radical of from 1 to 4 carbon atoms and R.sup.3 is an alkyl radical of from 1 to 18 carbon atoms or phenyl, tolyl or benzyl. It is useful for nonlinear optics.

Abstract: A process for the preparation of optical materials from silicon nitride by pyrolysis of polymeric silazanes, by pressing the pulverulent polymeric silazanes to give moldings before the pyrolysis or first dissolving the polymeric silazanes in an organic solvent, drawing fibers from this solution and pyrolyzing these fibers after evaporation of the solvent, or by melting polymeric silazanes, casting, injection-molding or extruding this melt to give moldings and subsequently pyrolyzing the moldings. An oxidic coating is produced on the silicon nitride molding in an oxygen-containing atmosphere during or after the pyrolysis. The pyrolysis can be carried out at 800.degree.-1000.degree. C. in an atmosphere containing ammonia or an ammonia/inert gas mixture.

Abstract: Radiation-sensitive film composed of at least one monomolecular layer of fluorine-containing amphiphiles. If a vinyl monomer containing fluoroalkyl side groups is copolymerized with a vinyl monomer containing oxirane groups, an amphiphilic polymer is obtained. To prepare a sandwich, a polymer is dissolved in a volatile organic solvent which is immiscible with water, the solution is spread on the water/air boundary surface, the resultant layer is compressed after the solvent has evaporated and transferred to a solid layer support by the Langmuir-Blodgett technique. The oxirane rings are cleaved and the film crosslinked by the action of high-energy radiation on the film.

Abstract: Amphiphilic copolymers containing silanyl groups and composed of derivatives of acrylic and/or methacrylic acid are described, which copolymers are suitable for the production of layer elements by the Langmuir-Blodgett method. Layer elements of this type can be used for optical waveguide systems and for the production of optical filters and for lithographic purposes.

Abstract: Polyamides of the general formula [N(A)-X-N(B)-CO-Y-CO-].sub.n are described, in which Y denotes a divalent group, X a divalent radical whose chain contains at least two carbon atoms, A and B independently of one another denote H or a C.sub.1 to C.sub.26 alkyl group and n denotes an integer greater than 4. The said polyamides contain at least one alkyl group of C.sub.6 to C.sub.26 per repeating unit. The groups X and/or Y contain at leat one CH.sub.2 group in the chain. The polyamides are prepared by reaction of a diamine of the formula NHA-X-NHB with an about equimolar amount of a reactive derivative of a dicarboxylic acid of the formula COOH-Y-COOH. The polyamides obtained can be used in order to prepare highly ordered monomolecular LB films on a support. For this purpose, the polyamide is dissolved in a volatile organic solvent which is immiscible with water and the solution is spread on the water/air interface.

Abstract: An electrically conductive resist material is disclosed, comprising at least one polymer which is sensitive to ionizing radiation and a soluble electrically conductive oligomer or polymer. A process for producing the resist material is also described, comprising admixing an electrically conductive oligomer or polymer dissolved in a solvent to at least one polymer which is sensitive to ionizing radiation. The resist material is useful in preparing electron beam resists which prevent electrostatic charging and resultant electrostatic fields.

Abstract: Amphiphilic monomers with mixed-chain structures of the formula ##STR1## in which Y denotes --O-- or --NH--X denotes a group of the formula --(CH.sub.2).sub.n -- or --(CH.sub.2 --O--CH.sub.2).sub.n --l denotes an integer from 0 to 10,n denotes an integer from 1 to 10,R.sup.1 denotes hydrogen, methyl, chlorine, cyano, fluorine or bromine,R.sup.2 denotes C.sub.1 -C.sub.24 -alkyl or C.sub.1 -C.sub.24 -fluoroalkyl andR.sup.3 denotes C.sub.8 -C.sub.24 -alkyl or C.sub.8 -C.sub.24 -fluoralkyl, with the proviso that the groups R.sup.2 and R.sup.3 contain a different number of carbon atoms. The monomers are polymerized on their own or together with other comonomers. The polymers obtained are suitable for the preparation of ultra-thin layers on a suitable layer support.

Abstract: Amphiphilic monomers having mixed-chain structures of the general formulae (I) or (II) ##STR1## where Y is --O-- or --NH--,X is a group of the formula --(CH.sub.2).sub.n -- or --(CH.sub.2 --O--CH.sub.2).sub.n --,l is an integer from 0 to 10,m is an integer from 10 to 26,n is an integer from 1 to 10,R.sup.1 is hydrogen, methyl, chlorine, cyano, fluorine or bromine, andR.sup.2 is O-alkyl or NH-alkyl,are polymerized alone or together with other comonomers. The polymers obtained are suitable for preparing ultra-thin films on a suitable base material.

Abstract: A polyurea of the general formula ##STR1## where X and Y are. independently of one another, a divalent radical whose chain contains in each case at least two carbon atoms, and A and B are, independently of one another, H or (C.sub.1 -C.sub.26)alkyl, and n is an integer greater than 4, which polyurea contains at least one (C.sub.6 -C.sub.26) alkyl group per repeating unit, is prepared by reacting the diamine NHA-X-NHB with roughly the equimolar amount of a diisocyanate OCN-Y-NCO. The polyurea is suitable for preparing ordered monomolecular LB films on a base (film-substrate-system). For this purpose it is dissolved in a volatile organic solvent which is not miscible with water, the solution is spread at the water/air interface, and the layer formed is compressed after the solvent has evaporated and it is transferred to a solid layer base by the Langmuir-Blodgett technique.

Abstract: A film for use in nonlinear optics comprises at least one Langmuir-Blodgett layer, the layer containing or comprising a dye of the formula ##STR1## in which R.sup.1 denotes a long-chain alkoxy, acyloxy, alkylamino or acylamino group. In particular when the film contains alternating layers of unsaturated amphiphilic compounds, it produces a stable multilayer having good nonlinear optical properties and is suitable, for example, for electrooptical switches, diode laser frequency amplifiers or optical parametric amplifiers.Besides the dye indicated, the unimolecular layer can additionally contain at least one second amphiphilic compound. In this case, the unimolecular layer comprises amphiphilic compounds.

Abstract: The film consists of one or more Langmuir-Blodgett layers, the layer containing an organic polymer having long-chain fluoroalkyl side groups or consisting of this compound. The film is distinguished by a multilayer structure having few defects and is, for example, suitable for optical purposes and for surface treatment. The order of the molecules in the multilayer can be improved by annealing and by heating the film through the phase transition and cooling again.