Materials Literature
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A novel two-step method combining rubbing and UV-irradiation based on ladderlike polysilsesquioxanes (LPS) containing cinnamate and azobenzene side chains was developed to obtain alignment layers which features a high surface pretilt angle and good stability. At the first step, a low pretilt angle of 1–3° was generate…
We have performed a preliminary study by light transmission of the electro-optical behaviour of several cells prepared either from hydroxypropylcellulose (HPC) or HPC with cellulose acetate (CA) (1% w/w) cross linked in both cases with 1,4-diisobutanocianaie (BDI) (7%w/w) and different concentrations of a commercial n…
Preparation of silicon-organic films for LC alignment is described. Effect of the molecular structure of organic substituents in siloxane chains on type of LC the alignment (homeotropic, tilted, planar) is considered. Contribution of polar and dispersion parts of the surface energy of siloxane films is discussed.
Using the continuum theory the influence of the external magnetic field on the ferrocholesteric — ferronematic phase transition is analyzed. The field being applied normal to the helix. Soft homeotropic coupling between the magnetic particles and the cholesteric molecules is assumed. The diamagnetic anisotropy of the…
The method presented in this paper pertains to an optical roughness meter that considers a fabric in all surface directions. A previous paper presented a tribological method for investigating textile fabrics, which used a roughness meter with a contact between the probe and the surface. However, a contact is not alway…
Anisotropy induction in the azo-polymer introduced into microporous glass under irradiation with polarised UV light is investigated. Practically pure “angular hole burning” mechanism is realised. Influence of the porous matrix on the life-time of cis-isomers, dipol-dipol interaction of polymer side chains, main-chain…
Thermoluminescence (TL) and thermally stimulated exoelectron emission (TSEE) in calcium phosphate doped with rare earth ions, such as Dy or Tm, have been studied, because its effective atomic number is close to that of human bones and teeth. It is found that Ca3(PO4)2 doped activators show the TL and TSEE sensitivity…
tert -Butylcatechol (TBC) is an efficient inhibitor of parasitic polymerization of many monomers during their transportation and storage. Just before the monomers are used, removal of the inhibitor is often necessary and can easily be achieved by adsorption on alumina. The influence of the main physical parameters of…
New liquid crystalline materials of the general formula have been synthesized (R1, R2 are alkyl chains). Mesomorphic properties were determined using polarizing microscopy. All compounds showed very broad smectic C* phase (about 70–90 K) and the cholesteric phase. No smectic A phase was observed. In the smectic C* pha…
Treatment of [Fe(OEP)]2O with trichloroacetic acid (2.5-fold excess) results in the formation of (octaethylporphinato)(trichloroacetato)iron(III). Various crystalline solvates can be isolated, depending on the crystallization solvent. Initial crystallization with CHCl3/hexanes resulted in the isolation of a monoclinic…
Five new polyamideimides (PAI) were synthesized from five diacid chlorides with preformed imide rings and a telechelic α,ω-diamino-polyoxyethylene (Jeffamine JFA ED600). The diacid chloride monomers could be obtained in high yields (77–92%) from chlorinating the corresponding diacids which were obtained from the react…
The synthesis and properties of a new mesogenic/nonmesogenic copolymer system, namely the poly[6-(4′-methoxyazobenzene-4′-oxy)hexyl methacrylate]-co-poly[methyl methacrylate]s, are described. Copolymers containing 0.59 or greater mol fraction of the mesogenic side-groups exhibit nematic behaviour while those containin…
Nowadays, a modern physical theory becomes of a principle importance in understanding the complexities of the living world: the physics of lyotropic states of matter. We demonstrate here what kind of specification is necessary in the molecular description of lyomesogens, in the theory of elastic and flexoelectric phen…
High‐temperature (1200–1550 K) mechanical‐loss and shear‐modulus measurements were performed on fine‐grained magnesia‐ and magnesia/ytrria‐doped alumina at low frequency (10 −4 −10 1 Hz), using a forced‐vibration torsion pendulum. Anelastic and viscoplastic relaxation phenomena were observed, which may be associated w…
A new, high sensitive, thermoluminescent material SrSO4:Mo, Tb is reported. TL sensitivity is three times that of widely used CaSO4:Dy. Emission of the phosphor is in the near UV-blue region of the spectrum which falls in the most sensitive region of the common photomultiplier tubes. In addition to this, good linearit…
A new calorimeter is constructed to precisely measure the heat of wetting of cotton, regular viscose rayon, high wet strength viscose rayon, and Tencel®. Our purpose is to investigate the relationship between the heat of wetting and structural characteristics of fibers such as crystal and fiber structure, degree of cr…
An ellipsometric method is used to study the dispersion of the real ɛ 1 ( ω ) and imaginary ɛ 2 ( ω ) parts of the complex dielectric permittivity of single-crystal La 1− x Sr x MnO 3 ( x =0.1, 0.2, and 0.3) for energies from 100 meV to 5 eV at room temperature. It is found that, when lanthanum is replaced by strontiu…
Characterization of the structure and chemical composition of nickel oxide films formed on AISI 316L stainless steel by electrochemical anodic treatment in an aqueous electrolyte containing 560 g l−1 NaOH was made by electron microscopy and x-ray photoelectron spectroscopy (XPS). The depth chemical composition, thickn…
The theory of the torque balance method for azimuthal anchoring energy measurements is investigated in detail under a general case of anchoring strength relationships between two substrates and a generalized relationship equation is deduced. As an example, azimuthal anchoring energies of several polyimide (PI) materia…
Abstract Complexes of vinylene-bridged bis- and tris(octaethylporphyrin)s (bis(OEP)–M and tris(OEP)–M) with d8 transition-metal ions (M = Ni(II), Pd(II), and Pt(II)) were synthesized. Metalation of (E)-bis(OEP)–H2 was carried out under the same conditions as for the corresponding octaethylporphyrin complex (OEP–M), to…