Showing papers on "Lyotropic liquid crystal published in 1997"
TL;DR: In this article, the authors summarized the current understanding of Langmuir-blodgett (LB) films from a physical/structural point of view, including discussions of the deposition process, the layered nature of LB films, intralayer molecular packing, defects, stability, and phase transitions.
257 citations
TL;DR: In this article, the authors used multinuclear (2H, 13C, 29Si, 81Br) magnetic resonance spectroscopy, small-angle X-ray scattering, and polarized optical microscopy techniques to investigate molecular and mesoscopic organization in silicate−surfactant lyotropic liquid crystals with hexagonal and lamellar morphologies under highly alkaline conditions.
Abstract: Multinuclear (2H, 13C, 29Si, 81Br) magnetic resonance spectroscopy, small-angle X-ray scattering, and polarized optical microscopy techniques have been used to investigate molecular and mesoscopic organization in silicate−surfactant lyotropic liquid crystals with hexagonal and lamellar morphologies under highly alkaline conditions. Such systems cooperatively self-assemble following the addition of a basic aqueous solution containing anionic silicate oligomers (e.g., double-four-ring species) to an isotropic micellar solution of cationic surfactant molecules (e.g., cetyltrimethylammonium bromide). Important similarities and differences are shown to exist between multicomponent silicate−surfactant and conventional binary lyotropic liquid crystals. Under highly alkaline conditions, the silicate−surfactant systems possess the characteristics of ordinary lyotropic liquid crystalline systems, though the balance of forces underlying their self-assembly is complicated by the richness of the aqueous silicate chemi...
230 citations
TL;DR: The location of the oils in the different self-assembled microstructures has been deduced from the structural dimensions obtained from SAXS and the constraints imposed by the copolymer total volume fraction and interfacial area.
Abstract: Amphiphilic block copolymers can self-assemble in the presence of selective solvents (water and oil) into a variety of different microstructures. The role that oil plays in the phase behavior and structure of copolymer-oil-water systems is the focus of the present investigation. We examined a poloxamer-type poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) triblock copolymer (Pluronic F127: E 100 P 70 E 100 ) in ternary isothermal systems with water and each of three oils (of varying polarity), p-xylene, n-butyl acetate and butan-1-ol. A total of six phases with different microstructures have been identified in the ternary systems studied here: normal (oil-in-water) micellar cubic (I 1 ), normal hexagonal (H 1 ), lamellar (L α ), and reverse (water-in-oil) hexagonal (H 2 ) lyotropic liquid crystals, and normal micellar (L 1 ) and reverse micellar (L 2 ) solutions. The number and types of phases, as well as the composition range of their stability, are different for each ternary system, reflecting the effects of oil. Systematic small-angle X-ray scattering (SAXS) measurements have been performed in order to establish the structure of the phases and determine their characteristic length-scales. The location of the oils in the different self-assembled microstructures has been deduced from the structural dimensions obtained from SAXS and the constraints imposed by the copolymer total volume fraction and interfacial area: all xylene is present in the interior (apolar core) of the oil-in-water microdomains and butanol is located at the interfacial region between poly(propylene oxide) and poly(ethylene oxide), while butyl acetate contributes to both the core and the interfacial domains.
128 citations
TL;DR: In this paper, an amphiphilic diblock copolymer composed of poly(ethylene oxide) and poly(butylene oxide) in the presence of water (selective solvent for PEO) and p-xylene, a selective solvent for poly(xylene), was shown to form six lyotropic liquid crystalline and two solution (equilibrium) phases.
Abstract: Six lyotropic liquid crystalline and two solution (equilibrium) phases can be formed (at 25 °C) by an amphiphilic diblock copolymer composed of poly(ethylene oxide) and poly(butylene oxide) in the presence of water (selective solvent for PEO) and “oil” (p-xylene, a selective solvent for PBO). Oil-in-water (“normal”) micellar solution (L1), micellar cubic liquid crystals (I1), hexagonal liquid crystals (H1), and a lamellar structure (Lα) are formed with an increase of the copolymer concentration along the oil-lean side of the ternary phase diagram. A micellar solution (L2), micellar cubic liquid crystals (I2), hexagonal liquid crystals (H2), and bicontinuous cubic liquid crystals (V2), all of the water-in-oil (“reverse”) morphology, are formed in the water-lean part of the phase diagram with increasing copolymer concentration and in the presence of some water. The oil-in-water [water-in-oil] structures can accommodate up to 0.33 [0.40] g of oil [water]/g of copolymer. The formation of a reverse micellar cu...
127 citations
TL;DR: In this paper, a three dimensional continuous space Monte Carlo computer simulation study is presented to discuss the extension of flexible, linear polymer chains due to the presence of equally flexible side chains.
Abstract: A three dimensional continuous space Monte Carlo computer simulation study is presented to discuss the extension of flexible, linear polymer chains due to the presence of equally flexible side chains. We consider the enhancement of the persistence length of bottle-brush structures in an athermal solution due to steric interactions between the side chains, The largest structure studied consists of a backbone of 100 beads with 50 side chains of 20 beads each, The persistence length lambda is evaluated in two different ways using the radius of gyration of the backbone and the bond angle correlation function, respectively. A correct description of the backbone conformations is shown to require at least two characteristic lengths. At a small length scale the backbone behaves flexible; the extension occurs at a larger length scale. There is a strong indication that the ratio between the persistence length and the diameter, which is the determining factor for lyotropic behavior of conventional semiflexible chains, levels off as a function of the side chain length. The value of this ratio is, moreover, too small to induce lyotropic behavior along this line. Recent experimental observations of lyotropic behavior of polymacromonomers are discussed in terms of these findings. (C) 1997 American Institute of Physics.
120 citations
TL;DR: The thermotropic mesophases of these compounds were studied by thermal polarizing optical microscopy and differential scanning calorimetry, and some also by X-ray scattering as mentioned in this paper.
Abstract: Novel amphiphilic glucamine derivatives have been synthesized. These are N-benzoyl-1-deoxy1-methylamino-D-glucitols and N-benzoyl-1-amino-1-deoxy-D-glucitols carrying one, two or three aliphatic chains (CnH2n 1O- with n 3, 6 and 12) grafted to the benzamido group. The thermotropic mesophases of these compounds were studied by thermal polarizing optical microscopy and differential scanning calorimetry, and some also by X-ray scattering. Depending on the number and the length of the alkyl chains lamellar, bicontinuous cubic, hexagonal columnar or inverted micellar cubic mesophases were detected by analogy with lyotropic systems. In the contact region between lamellar phases of the single chain amphiphiles and micellar cubic phases of the mesomorphic triple chain compounds, hexagonal columnar phases can be induced. A hexagonal columnar phase was also induced in the contact region between a bicontinuous and a micellar cubic mesophase. The lyotropic liquid crystalline behaviour of the dodecyloxy substituted N-...
101 citations
Journal Article•
TL;DR: In this article, an amphiphilic diblock copolymer composed of poly(ethylene oxide) and poly(butylene oxide) in the presence of water (selective solvent for PEO) and p-xylene, a selective solvent for poly(xylene), was shown to form six lyotropic liquid crystalline and two solution (equilibrium) phases.
Abstract: Six lyotropic liquid crystalline and two solution (equilibrium) phases can be formed (at 25 °C) by an amphiphilic diblock copolymer composed of poly(ethylene oxide) and poly(butylene oxide) in the presence of water (selective solvent for PEO) and “oil” (p-xylene, a selective solvent for PBO). Oil-in-water (“normal”) micellar solution (L1), micellar cubic liquid crystals (I1), hexagonal liquid crystals (H1), and a lamellar structure (Lα) are formed with an increase of the copolymer concentration along the oil-lean side of the ternary phase diagram. A micellar solution (L2), micellar cubic liquid crystals (I2), hexagonal liquid crystals (H2), and bicontinuous cubic liquid crystals (V2), all of the water-in-oil (“reverse”) morphology, are formed in the water-lean part of the phase diagram with increasing copolymer concentration and in the presence of some water. The oil-in-water [water-in-oil] structures can accommodate up to 0.33 [0.40] g of oil [water]/g of copolymer. The formation of a reverse micellar cu...
84 citations
Patent•
13 Aug 1997TL;DR: A new structural class of amphiphilic molecules which incorporate a hydrophilic material or polymer attached, at spatially distinct sites, to at least two hydrophobic residues is described in this article.
Abstract: Disclosed is a new structural class of amphiphilic molecules which incorporate a hydrophilic material or polymer attached, at spatially distinct sites, to at least two hydrophobic residues. Certain of the amphiphilic molecules comprise a plurality of hydrophobic moieties. All such amphiphilic molecules have a common structural motif and, in contact with water, display surface activity and self-assemble into multimolecular aggregates and liquid crystalline phases. Also disclosed are enhanced stability liposomes that incorporate such amphiphilic molecules via unique interactions, and methods of using such formulations in a variety of applications including drug delivery, nutrition, bio-diagnostics, cosmetics, blood products and related applications.
74 citations
TL;DR: In this article, the authors presented neutron diffraction data from a novel, biologically relevant, lyotropic membrane system which is highly alignable (#1.0± mosaic) in a magnetic field and gives rise to a number of welldefined Bragg reflections.
Abstract: This Letter presents neutron diffraction data from a novel, biologically relevant, lyotropic membrane system which is highly alignable (#1.0± mosaic) in a magnetic field and gives rise to a number of welldefined Bragg reflections. The system, composed of two different phosphorylcholine lipids, undergoes a rare nematic ! smectic phase transition upon doping the system with paramagnetic ions (e.g., 2.7 wt % Tm31). In addition, the isotropic phase occurs at a lower temperature than the smectic phase, in contrast to other lyotropic systems and in contrast to the phase behavior predicted by the McMillan model [Phys. Rev. A 4, 1238 (1971)] of smectic ordering. [S0031-9007(96)02290-9]
64 citations
57 citations
TL;DR: In this article, a review of the self-assembly of lecithin in non-aqueous media is presented, focusing on the dependence of selfassembly at the macroscopic level on interactions at the molecular level, shape of molecules, and their solvation and packing at the interface.
Abstract: Modern concepts of the self-assembly of amphiphiles are considered on the example of self-organising structures of the natural lecithin. Binary, ternary and multicomponent systems are discussed. A considerable part of the review is devoted to the peculiarities of self-organisation of this phospholipid in non-aqueous media and to the role of polar inorganic solvents. Virtually all of the structures formed by lecithin are examined: micelles, swollen micelles, microemulsions, emulsions, organogels, vesicles (liposomes), and lyotropic liquid crystals. In each specific case, attention is drawn to the dependence of self-assembly at the macroscopic level on interactions at the molecular level, shape of molecules, and their solvation and packing at the interface. The self-organising lecithin structures formed in the interfacial area of immiscible liquids in the course of unrestricted adsorption from the bulk of non-aqueous solution are considered. The bibliography includes 282 references.
TL;DR: In this article, the synthesis of cadmium sulfide containing a periodic array of nanometer-sized cylindrical pores was reported. But the results were limited to a hexagonal lyotropic liquid crystal.
Abstract: We report the synthesis of cadmium sulfide containing a periodic array of nanometer-sized cylindrical pores. The nanostructured cadmium sulfide was synthesized in a hexagonal lyotropic liquid crystal by the reaction between H2S and various cadmium salts. Interestingly, the counterion of the cadmium salt had a pronounced effect on the regularity and periodicity of the pores. The dimension of the pores is commensurate with the hydrophobic cores of the liquid crystal, and one counterion even leads to hexagonally faceted nanostructured particles.
TL;DR: In this article, the phase equilibria in mixtures of egg lecithin and cetyltrimethylammonium chloride in brine (100 mM sodium chloride) were studied with particular emphasis on the behavior of the lamellar phase.
Abstract: The phase equilibria in mixtures of egg lecithin and cetyltrimethylammonium chloride in brine (100 mM sodium chloride) were studied with particular emphasis on the behavior of the lamellar phase. The solvent corner of this pseudoternary system features an extensive lamellar phase which we have characterized by means of cryo-transmission electron microscopy (cryo-TEM), small-angle X-ray diffraction, and 2H and 31P NMR. The cryo-TEM micrographs illustrate a smooth transition in aggregate microstructure between lamellar and micellar structures with a perforated lamellar structure as an intermediate state. The findings from X-ray diffraction and NMR spectroscopy also indicate a deviation from ordinary bilayer structures in the solvent rich region of the lamellar phase. This is concluded from strongly nonideal swelling and progressively decreasing 2H NMR quadrupole splittings of the deuterated cetyltrimethylammonium chloride inside the lamellar region. The correlation between the observed aggregate structures ...
TL;DR: The phase behavior and microstructure in ternary systems composed of an amphiphilic copolymer, an aqueous solvent (water) and an organic solvent (oil) are the subjects of an ongoing investigation by as mentioned in this paper.
TL;DR: The synthesis and properties of mesogen-jacketed liquid crystal polymers are reported in this article, showing that the polymers have very high glass transition temperatures as well as very low critical concentrations for the formation of the lyotropic liquid crystal phase.
Abstract: The synthesis and property of a new series of "mesogen-jacketed liquid crystal polymers" are reported. These polymers have aromatic amide structures as the mesogenic groups and are represented by poly-2,5-bis(4-methoxy- benzamido)styrene. The preliminary study on properties shows that the polymers have very high glass transition temperatures as well as very low critical concentrations for the formation of the lyotropic liquid crystal phase. The results indicate a high degree of chain rigidity. However, the liquid crystalline order of molecular organization in bulk samples disappears upon heating to the glass transition temperature as revealed by polarizing microscopy and by X-ray diffractometer. Therefore, the liquid crystalline order of these polymers forms only through solution but not through heating. This behavior is different from that of the previously studied poly-2,5-bis[(4-methoxybenzoyl)oxy]styrene and its homologs. The latter polymers are liquid crystals both lyotropically and thermotropically. © 1997 John Wiley & Sons, Ltd.
TL;DR: In this paper, the authors developed a specific cell for X-ray diffraction in order to determine the gel structure, which has a two-dimensional hexagonal structure similar to the inverted hexagonal phase of lyotropic liquid crystals.
Abstract: Bis[1,2-bis(3,4-di-n-alkoxyphenyl)ethanedione dioximato]palladium(II) complexes (abbreviated as [Pd{(CnO)4dpg}2]; n = 7—12) form gels in an over-concentrated n-hexane solution. We have developed a specific cell for X-ray diffraction in order to determine the gel structure. The gel has a two-dimensional hexagonal structure which is similar to the inverted hexagonal phase of lyotropic liquid crystals. The electronic spectra were measured for the gel and for a chloroform solution, which dose not form a gel. As a result, it has become apparent that a 4dz2–5pz intermolecular charge-transfer transition between the neighboring palladium ions is the main driving force of the gel formation. The circular dichroism and magnetic circular dichroism of the gel suggested that this complex has a stack of left-handed helicity. The complex also has a thermotropic liquid-crystalline state, as previously reported. Hence, these three kinds of states are closely related to each other in terms of the formation of molecular aggr...
TL;DR: In this article, the cholesteric phase in aqueous lyotropic liquid crystals doped with cellulose derivatives has been studied utilizing hot stage polarized microscopy, where three ionic surfactantssodium decyl sulfate, cesium pentadecafluorooctanoate, and myristyltrimethylammonium bromidewere employed to obtain anionic or cationic lyonematics.
Abstract: Formation of the cholesteric phase in aqueous lyotropic liquid crystals doped with cellulose derivatives has been studied utilizing hot stage polarized microscopy. Three ionic surfactantssodium decyl sulfate, cesium pentadecafluorooctanoate, and myristyltrimethylammonium bromidewere employed to obtain anionic or cationic lyonematics. After addition of chiral polymers (at polymer concentration ∼0.05−0.750 wt %) the samples were sealed in flat glass capillaries, and a magnetic field was applied to enhance the homogeneous orientation and formation of the fingerprint texture. Out of seven various cellulosic derivatives (five nonionic, one cationic, and one anionic), nonionic hydroxypropyl cellulose was the only compound that induced the cholesteric phase. The effective helical twisting power (HTP) of hydroxypropyl cellulose is 3−4 times higher in anionic lyonematics than in cationics. In both cationic and anionic media, the HTP decreases with an increase in the molecular weight of the chiral polymer. This beh...
TL;DR: In this paper, the geometry of the structures, based on frustration analysis, can account for the sequence of phases observed in these systems, independent of the chemical nature of the amphiphilic molecules.
TL;DR: In this article, a series of novel aromatic polyamides containing 2,2′-bipyridine moiety were synthesized by polycondensation of 2.2.bipridine-5,5′-dicarboxylic acid (2) with various aromatic diamines in hexamethylphosphoramide (HMPA) containing lithium chloride.
Abstract: A series of novel aromatic polyamides containing 2,2′-bipyridine moiety were synthesized by polycondensation of 2,2′-bipyridine-5,5′-dicarboxylic acid (2) with various aromatic diamines in hexamethylphosphoramide (HMPA) containing lithium chloride. The resulting polyamide solutions in 98% sulfuric acid and in HMPA-LiCl exhibited lyotropic liquid crystal phases. The phase transition behaviors were studied by polarizing microscopy and X-ray diffraction. The polyamides also formed metal complexes with cis-dichlorobis(bipyridine)ruthenium dihydrate [cis-Ru(bpy)2Cl2 · 2H2O] which was supported by changes in electronic spectra.
TL;DR: The discotic amphiphile TP6EO2M, in aqueous solution, assembles into columnar aggregates which in turn undergo self-organisation on longer length scales to produce a rich variety of mesophases as mentioned in this paper.
Abstract: The discotic amphiphile TP6EO2M, in aqueous solution, assembles into columnar aggregates which in turn undergo self-organisation on longer length scales to produce a rich variety of mesophases.1-3 Adding an electron deficient dopant such as TNF or TAPA leads to the stabilisation of these mesophases and has the potential to introduce new properties such as chirality.
TL;DR: In this paper, the twist-grain-boundary phase of chiral lamellar phases as well as the isolated helicoidal defects were described, and the authors showed that the centers of these defects are hollow and thus their energy cost comes from the line energy of an exposed laminate surface.
Abstract: The molecules in lyotropic membranes are typically aligned with the surface normal. When these molecules are chiral, there is a tendency for the molecular direction to twist. These competing effects can reach a compromise by producing helicoidal defects in the membranes. Unlike thermotropic smectics, the centers of these defects are hollow and thus their energy cost comes from the line energy of an exposed lamellar surface. We describe both the twist-grain-boundary phase of chiral lamellar phases as well as the isolated helicoidal defects.
Patent•
04 Jun 1997
TL;DR: In this paper, the problem of aligning a photo-active molecule layer is solved by diagonal irradiation with light including light which is absorbed in the photoactive molecules or by irradiation of linear polarized light and a lyotropic liq. crystal is brought into contact with the oriented photoactive molecular layer.
Abstract: PROBLEM TO BE SOLVED: To finely and stably orient a lyotropic liq. crystal contg. a solvent by bringing the liq. crystal into contact with an oriented photo-active molecule layer. SOLUTION: A photo-active molecule layer is oriented by diagonal irradiation with light including light which is absorbed in the photo-active molecules or by irradiation with linear polarized light and a lyotropic liq. crystal is brought into contact with the oriented photo-active molecule layer. The photo-active molecule layer is usually formed on a substrate. This substrate may be any substrate to which clichroic molecules can bond and a sheet of silica glass, hard glass, quartz or plastic optionally surface-coated with a metal oxide such as silicon dioxide or tin oxide, silicon nitride or silicon carbide may be used. The dichroic molecules can cause to vary orientation of molecular axes by the action of light. COPYRIGHT: (C)1998,JPO
TL;DR: In this article, the influence of a ferrofluid on the surface properties of lyotropic liquid crystals doped with magnetic particles was investigated. But the experimental results were limited to the case of a single particle.
Abstract: We report the first experimental investigation devoted to analyze the influence of a ferrofluid on the surface properties of lyotropic liquid crystals doped with magnetic particles. By means of optical methods, the bulk orientation of the director vs the temperature is determined. The theoretical analysis shows that near the nematic–isotropic transition, the thermodynamical model for the temperature surface transition works reasonably well. On the contrary, in the low temperature region near the lamellar–nematic transition, important deviations from the theoretical behavior are observed. In order to interpret our experimental data, we propose a simple phenomenological extension of the thermodynamical model that takes into account the different contributions to the surface energy and of the residual lamellar order in the nematic phase. We show, furthermore, that the effective splay-bend elastic constant depends on the ferrofluid doping concentration, in agreement with a recently proposed theory.
TL;DR: In this article, small particles were obtained by the chemical reaction of CUSO4 and urea in aqueous solution, anionic AOT-water and cationic CTAB-hexanol-water lamellar liquid crystals.
Abstract: Inorganic small particles were obtained by the chemical reaction of CUSO4 and urea in aqueous solution, anionic AOT-water and cationic CTAB-hexanol-water lamellar liquid crystals. X-ray diffraction and IR spectrum showed that different product were obtained from different systems. The product were CU4(OH)6SO4 for aqueous solution, an inorganic mixture for CTAB system and microcrystal containing organic groups for AOT system. The the products formed in liquid crystals are particles or sheet in shape and have narrow size distribution. Particle size increased with reaction time, but the rate of growth of the particle in aqueous solution is faster than in liquid crystals. Comparing the average diameter of the particles formed in three systems, the size was reduced in the following order: D(water)>D(CTAB-hexanol-water)>D(AOT-water).
TL;DR: In this paper, a theory of the reorientational phase transition in the biaxial surface layer of a lyotropic liquid crystal is proposed, which is induced by the calamitic-biaxial transformation in the bulk and is accompanied with qualitative changes in the orientation and dynamic behaviour of the gliding director which can be followed experimentally.
TL;DR: In this paper, small angle neutron scattering (SANS) was used to investigate the flow properties of the discotic micellar isotropic (I), nematic (N) and lamellar (L α) phases in aqueous solutions of cesium perfluoro-octanate.
Abstract: Small angle neutron scattering (SANS) has been utilized to investigate the flow properties of the discotic micellar isotropic (I), nematic (N) and lamellar (L α) phases in aqueous solutions of cesium perfluoro-octanate. Under simple shear, no preferred orientation was observed in the I phase. The N phase aligned with the nematic director along the shear gradient velocity, providing the first evidence for a positive value of the viscosity parameter, α2. The L α phase oriented with lamellae parallel to the shear plane. A reorientation of the director near the N-L α transition was witnessed upon cooling from the N phase at a constant shear rate and is attributed, primarily to a change in the value of α2 as a result of increasing lamellar correlations in the nematic phase. The application of oscillatory shear induced significant shifts in the phase boundaries, including nematic-like order some 7 K into the quiescent I phase.
Patent•
23 Jan 1997
TL;DR: In this paper, a method for improving a gas barrier property for holding performance of moisture proof property, pressure resistance, moisture keeping property, oxidation prevention, etc., and heat resistance, nonshrink property, strength, flexibility by a method wherein a metal or nonorganic oxide layer is formed on a side face or both faces of a liquid crystal polymer base material.
Abstract: PROBLEM TO BE SOLVED: To improve a gas barrier property for holding performance of moisture proof property, pressure resistance, moisture keeping property, oxidation prevention, etc., and heat resistance, nonshrink property, strength, flexibility by a method wherein a metal or nonorganic oxide layer is formed on a side face or both faces of a liquid crystal polymer base material. SOLUTION: A metal or an inorganic oxide layer 2 is provided on at least one face of a liquid crystal resin layer 1. As the liquid crystal layer 1, a lyotropic liquid crystal resin or thermoplastic liquid crystal resin is used. As the lyotropic liquid crystal resin, aromatic polyamide, polyphenylenebisbenzothiazol, etc., is used. As the thermoplastic liquid crystal resin, that which is obtained by copolimerization of aromatic diol, aromatic dicarboxylic acid, hydroxy carboxylic acid, aliphatic glycol, etc., is used. As the metal or inorganic oxide 2, oxides of silicon, titanium, magnesium, zirconium, etc., can be formed by a vacuum deposition method or the like.
TL;DR: In this article, a new approach to create mesomorphic ordered systems is discussed based on the idea to use noncovalent interactions in the designing of thermotropic structures by modelling lyotropic liquid crystal (LC) when the water interlayer is changed by appropriate solid substances that are able to interact with the polar part of an amphiphilic molecule without any strong change in the intermolecular interactions between the non-polar tails.
Abstract: A new approach to create mesomorphic ordered systems is discussed. It is based on the idea to use noncovalent interactions in the designing of thermotropic structures by modelling lyotropic liquid crystal (LC) when the water interlayer is changed by appropriate solid substances that are able to interact with the polar part of an amphiphilic molecule without any strong change in the intermolecular interactions between the non-polar tails.
TL;DR: In this paper, the authors measured the fluctuations of a lyotropic liquid crystal lamellar (Lα) phase in dilute surfactant concentration and a sponge (L3) phase by dynamic light scattering technique.
Abstract: We measured the fluctuations of a lyotropic liquid crystal lamellar (Lα) phase in dilute surfactant concentration and a sponge (L3) phase by dynamic light scattering technique. We observed the concentration fluctuation induced by the thermal undulation of layers in the Lα phase and obtained the dependence of the effective rigidity kc of layers on the repeat distance d, which reflected the fluctuation-induced layer softening. In the L3 phase, two kinds of fluctuation modes were observed.