Abstract:
Verwendung der Verbindungen der Formel R1 C12-C26-Alkyl oder C12-C26-Alkenyl, n eine Zahl von 0 bis 5, C1-C3-Alkyl, R3 C1-C3-Alkyl oder eine Gruppe der Formel -(C2H4O)xH, x eine Zahl von 1 bis 3, A ein Anion, R9 eine Gruppe der Formel R1'-(OCH2CH2)n-, C8-C18-Alkylaryl oder Aryl-C8-C18-alkyl, R1' C14-C22-Alkyl oder C14-C22-Alkenyl, n eine Zahl von 0 bis 5 und die Reste R10 gleich sind und C1-C4-Alkyl oder C1-C4-Hydroxialkyl bedeuten, als Korrosionsschutzmittel für metallische Werkstoffe in wässrigen Medien.
Abstract:
Switching and display elements based on ferroelectric liquid-crystals often exhibit a pronounced optical hysteresis which results in the appearance of so-called ghost images. This phenomenon can be markedly reduced or even suppressed if at least one of the two orienting layers are in direct contact with the electrodes and is composed of an electrically conductive polymer of the formula (I): (I) in which R1, R2=independently of each other, H, or straight-chain or branched alkyl or alkoxy containing 1-16 carbon atoms, or halogen, X=S, NH, Y-=BF4-, PF6-, PO43-, AsF6-, SbCl6-, SO42-, HSO4-, alkyl-SO3-, perfluoroalkyl-SO3-, aryl-SO3, F- or Cl-, and n is an integer from 4 to 100 and m is an integer from 1 to 30.
Abstract:
The novel silylalkyl or -alkenyl compounds conform to the general formula (I) in which A , A and A are aromatic or heteroaromatic molecular units such as 1,4-phenylene or pyrimidine-2,5-diyl which are linked via a single bond (where k and m are zero) or via functional groups M and M , such as CO-O or CH2-O; j, k, l, m and n are zero or 1 (j + l + n = 2 or 3), the radicals R , R , R and R are H or alkyl/alkenyl or cycloalkyl, the radicals R , R and R have a comparable meaning (H); R is alkyl/alkenyl or a substituent known from LC chemistry, such as an alpha -haloalkanoic acid radical. The compounds have liquid-crystalline phases, which are in some cases broad and polymorphous.
Abstract:
Use of the compounds of the formula in which R1 denotes C12-C26-alkyl or C12-C26alkenyl, n denotes a number from 0 to 5, K(+) denotes a group of the formulae or a group of the formula -(C2H4O)xH, x denotes a number from 1 to 3, A(-denotes an anion, R9 denotes a group of the formula R1'-(OCH2CH2)n-, C8-C18-alkylaryl or aryl-C8-C18-alkyl, R1' denotes C14-C22-alkyl or C14-C22-alkenyl, n denotes a number from 0 to 5 and the radicals R10 are identical and denote C1-C4-alkyl or C1-C4-hydroxyalkyl, as corrosion protection agents for metallic materials in aqueous media.
Abstract:
The novel liquid crystalline mixtures, which additionally contain an optically active compound as a dopant in the case of ferroelectric behaviour are based on at least 2 components of the general formula (I) and at least one carboxylic ester of the general formula (XI) or (XII) in which x is an integer of from 2 to 14 and n is an integer of from 6 to 14 in which a and b independently of one another may denote an integer of from 2 to 14 and -X- may denote an or an -O- group; in which A denotes, for example, pyrimidine-2,5-diyl, -Y- denotes, for example, -O- or -S-, -M- denotes, for example, -O- or -CH2-, -R denotes, for example, CH3 and c, d and e denote, for example, integers such as 2, 3 or 4. The mixtures, which may also contain further components, have advantageous properties for use in electrooptical display elements, such as low melting points and low crystallisation temperatures.
Abstract:
Optically active 1,3 dioxolane derivatives containing a mesogenic residue, of the general formula (I), are suitable as doping agents especially in ferro-electrical liquid crystal mixtures. The meanings of the symbols in the general formula are: R is constructed similarly to the part of the general formula to the right of X or an alkyl or alkylene residue which may be substituted; R , R , R = H or alkyl (R may also be alkenyl) which may also be substituted [R , R together with the C(2) of the dioxolane ring may be a cycloaliphate or a keto group]; j, l, n = zero, 1 or 2 and k, m = zero or 1 provided that if k = zero, n = zero also, if n = zero, m = zero also and l , -A , -A = aromatic, heterocyclic or aliphatic ring system; -M ,- M = -CO-O, -O-CO, -CH2CH2, -CH=CH, -CH2O, -OCH2, -C=C and X = CH=CH, CH2-CH2. The special advantage of the compounds with the general formula (I) is that they can induce a high twisting capacity in a cholesteric phase without substantially affecting in the smectic C* phase the value of the spontaneous polarisation already in the mixture. They are therefore suitable for pitch compensation, especially for ferro-electrical liquid crystal mixtures.
Abstract:
The novel silylalkyl or -alkenyl compounds conform to the general formula (I) in which A , A and A are aromatic or heteroaromatic molecular units such as 1,4-phenylene or pyrimidine-2,5-diyl which are linked via a single bond (where k and m are zero) or via functional groups M and M , such as CO-O or CH2-O; j, k, l, m and n are zero or 1 (j + l + n = 2 or 3), the radicals R , R , R and R are H or alkyl/alkenyl or cycloalkyl, the radicals R , R and R have a comparable meaning (H); R is alkyl/alkenyl or a substituent known from LC chemistry, such as an alpha -haloalkanoic acid radical. The compounds have liquid-crystalline phases, which are in some cases broad and polymorphous.
Abstract:
Optically active tetrahydrofuran-2-carboxylic acid esters containing a mesogenic molecular building block are suitable as dopes in liquid-crystal mixtures. They result in liquid-crystalline ferroelectric phases having short switching times and in electroclinic phases having high electroclinic coefficients. A further advantage is that they induce a helix of very low pitch, so they are also suitable for helix compensation in LC mixtures. The compounds are symbolised by the general formula in which the symbols and indices essentially have the following meanings: R = alkyl/alkenyl or tetrahydrofurancarbonyloxy or -thio; j, l and n = zero, 1 or 2; k and m = zero or 1; -A , -A and -A = phenylene, cycloalkylene or corresponding N-, O- or S-containing heterocycles; -M and -M = bridges, such as -CO-O-, -OCH2- or -CH=CH-; and X = O or S.