Liquid crystalline matrix

The host liquid crystalline matrix was composed of water, sodium octanoate and octanol. This combination was chosen in order to create an environment as closely matching the specific requirements of the problem as possible. In the first instance, the surfactant was Identical to the one used for the solubilization determinations (12) and the alcohol was present in order to resemble actual laundering conditions with "oily dirt" molecules present (12). 

Employing x-ray methods, Flaim and Friberg (2 ) studied the conformation of C21-DA as the acid or monosoap in a lamellar liquid crystalline matrix. At low water concentrations, the conformations are the same (extended). At somewhat higher water... 

Liquid crystals are classified into lyotropic and thermotropic crystals depending on the way in which the mesomorphic phase is generated. Lyotropic liquid-crystalline solvents are formed by addition of controlled amounts of polar solvents to certain amphiphilic compounds. Thermotropic liquid-crystalline solvents, simply obtained by temperature variations, can be further classified into nematic, smectic, and cholesteric solvents depending on the type of molecular order present. Liquid crystals are usually excellent solvents for other organic compounds. Nonmesomorphic solute molecules may be incorporated into liquid-crystalline solvents without destruction of the order prevailing in the liquid-crystalline matrix (Michl and Thulstrup, 1986). Ordered solvent phases such as liquid crystals have also been used as reaction media, particularly for photochemical reactions (Nakano and Hirata, 1982). 

Usually the surfactant concentration in ointments and creams is significantly lower than in surfactant gels. Ointments are non-aqueous preparations, whereas creams result from ointments by adding water. The microstructure of both ointments and creams may consist of liquid crystals, as long as a liquid crystalline network or matrix is formed by amphiphilic molecules. In a liquid crystalline matrix, it is easier to deform the system by shear such formulations show plastic and thixotropic flow behavior on shear. In comparison to systems with a crystalline matrix which are usually destroyed irreversibly by shear, those with a liquid crystalline matrix exhibit a short regeneration time of... 

Munzenmaier A, Rosch N, Weber S, FeUer C, Ohmes E and Kothe G (1992) Transient EPR of the spin-polarized triplet states of chlorophyll and retinal in liquid crystalline matrix Characterization of the overall and librational pigment dynamics. J Phys Chem 96 1(X)46-10653... 

Lee, K.W.Y. Nguyen, T.H. Hanley, T. Boyd, B.J. Nanostructure of liquid crystalline matrix determines in vitro sustained release and in vivo oral absorption kinetics for hydrophilic model drugs. Int. J. Pharm. 2009, 365 (1-2), 190-199. 

Boyd, B.J. Khoo, S.M. Whittaker, D.V. Davey, G. Porter, C.J.H. A lipid-based liquid crystalline matrix that provides sustained release and enhanced oral bioavailability for a model poorly water soluble drug in rats. Int. J. Pharm. 2007, 340 (1-2), 52-60. 

This reaction has been modified extensively to proceed under different conditions. For example, it has been performed in liquid crystalline matrixes, sg in zeolite,in supercritical C02, on a silica gel surface, or in the presence of cyclo-dextrin. In addition, this reaction has been catalyzed by photoacid. Moreover, this reaction has been extended to various substrates other than the regular phenyl (or aryl) esters as described earlier. 

This effect is a version of the splay-bend Frederiks transition, but it is observed in liquid crystals doped with dyes. The liquid crystalline matrix (the host) is subjected to the influence of a field the function of the dye (the guest) is to enable the effect to be seen with only one polarizer or even without any. 

Ferrocene-modified SWCNTs and ABTS-modified SWCNTs were deposited onto one of each electrode using a liquid-crystalline matrix-monoolein cubic phase. The GBFC delivered 100 pW cm— with an OCP of 0.43 V in 20 mM glucose in quiescent solution... 

Exclusively submicron particles obtained by high pressure homogenization were used in a study which compared skin interaction of GMO-based cubic nanoparticles (with additional vesicular structures as observed by cryo-TEM) with that of other lipidic nanoparticles with compact liquid, crystalline or thermotropic liquid crystalline matrix structure. The cubic nanodispersion, which was stable with respect to particle size for 15 months of storage at room temperature, increased skin permeation of the model substance corticosterone (used in trace amounts in this study) compared to the other types of lipid nanoparticles. Permeation from all lipidic dispersions was, however, lower than from an aqueous solution which was attributed to the retention of a certain fraction of the drug in the lipid nanoparticles. Considering only the drug present in the aqueous phase of the dispersion as available for transport through the epidermis, the presence of cubic GMO particles increased permeation by the factor 2.4. 

FIGURE 2.15. Absorption spectra of anthracene in a liquid crystalline matrix [29]. 

Liquid Crystalline Matrix Polymers for Speciality Application... 

Cellulose is the most abundant biopolymer on earth. It can be used in different applications, namely in the form of fibers, and cellulose can be converted into numerous cellulose derivatives. Cellulose micro- and nanofibers have been the subject of intense research in the field of composites. Cellulose derivatives can show liquid crystalline chiral nematic phases, which can be used for the production of diverse composite systems. All-cellulosic composites based on liquid crystalline cellulosic matrices reinforced by cellulose micro- and nanofibers can show enhanced mechanical properties due to fiber orientation induced by the liquid crystalline matrix. Cellulose-based fibers electrospun from liquid crystalline phases can develop different structures, which are able to mimic the shape of plant tendrils on the nano- and microscale, opening new horizons for ceDulosic membrane applications. 

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