X-ray scattering data of a three-component lamellar phase composed of oil (octane), water and a non-ionic surfactant (C l2 E 5 ) are shown for various surfactant concentrations as well as oil/water volume ratios, in order to study the periodicity of the layers as well as the effect of structural symmetry on their interactions and organization of the layers. The data are fitted with a recently proposed model which takes into account the geometry and the fluctuations of these repeated structures and gives a good fit for a highly fluctuating non-charged and non-oriented lamellar phase. The variation of the exponent n which characterizes the quasi-long range order indicates that the structure is more ordered for the most symmetrical system: i.e. for an oil/water ratio of 1.
{"title":"Effect of Symmetry on a Three-Component Lamellar Phase: X-ray Scattering Study","authors":"R. Oda, J. Litster","doi":"10.1051/JP2:1997153","DOIUrl":"https://doi.org/10.1051/JP2:1997153","url":null,"abstract":"X-ray scattering data of a three-component lamellar phase composed of oil (octane), water and a non-ionic surfactant (C l2 E 5 ) are shown for various surfactant concentrations as well as oil/water volume ratios, in order to study the periodicity of the layers as well as the effect of structural symmetry on their interactions and organization of the layers. The data are fitted with a recently proposed model which takes into account the geometry and the fluctuations of these repeated structures and gives a good fit for a highly fluctuating non-charged and non-oriented lamellar phase. The variation of the exponent n which characterizes the quasi-long range order indicates that the structure is more ordered for the most symmetrical system: i.e. for an oil/water ratio of 1.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"236 1","pages":"815-824"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90532288","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The behavior of solutions of polymer chains with anisotropic rigidity is considered theoretically. The diagrams of different scaling regimes and the phase diagrams for polymers with arbitrary contour length L, inplane rigidity l, and out of plane rigidity l2 are obtained. Two new types of nematic structures in addition to ordinary nematic with ordering of tangent vectors are found for the regime of moderate second rigidity $l_2~(l lesssim l_2 lesssim l^3/d^2 )$: a pancake nematic (with ordering of the normals to the planes of main flexibility of the chains) and a biaxial nematic (when both tangent and normal vectors are ordered). We also found smectic A and smectic C phases in addition to three nematic phases. The scaling (modified blob) and mean-field with correlation corrections approaches are developed and used when appropriate. Order parameters, correlation radii and chain sizes are discussed for most of the regimes.
{"title":"Highly anisotropic rigidity of ribbon-like polymers : III. Phase diagrams for solutions","authors":"I. Nyrkova, A. Semenov, J. Joanny","doi":"10.1051/JP2:1997159","DOIUrl":"https://doi.org/10.1051/JP2:1997159","url":null,"abstract":"The behavior of solutions of polymer chains with anisotropic rigidity is considered theoretically. The diagrams of different scaling regimes and the phase diagrams for polymers with arbitrary contour length L, inplane rigidity l, and out of plane rigidity l2 are obtained. Two new types of nematic structures in addition to ordinary nematic with ordering of tangent vectors are found for the regime of moderate second rigidity $l_2~(l lesssim l_2 lesssim l^3/d^2 )$: a pancake nematic (with ordering of the normals to the planes of main flexibility of the chains) and a biaxial nematic (when both tangent and normal vectors are ordered). We also found smectic A and smectic C phases in addition to three nematic phases. The scaling (modified blob) and mean-field with correlation corrections approaches are developed and used when appropriate. Order parameters, correlation radii and chain sizes are discussed for most of the regimes.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"155 7 1","pages":"847-875"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83150708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The influence of solubilized benzene on the viscosity of polysoaps is explained on the basis of a simple association model for the polysoap. This model assumes aggregation of the hydrophobic side chains into cylinders disposed along the chain backbone. Modification of the interfacial energies of the domains by adsorption of the aromatic molecules leads to a non-monotonic behaviour of the mean aggregate size, and a corresponding non-monotonic behaviour of the reduced viscosity of the polysoap solutions.
{"title":"Pollutant-Polysoap Interactions","authors":"Y. Rouault, C. Marques","doi":"10.1051/JP2:1997161","DOIUrl":"https://doi.org/10.1051/JP2:1997161","url":null,"abstract":"The influence of solubilized benzene on the viscosity of polysoaps is explained on the basis of a simple association model for the polysoap. This model assumes aggregation of the hydrophobic side chains into cylinders disposed along the chain backbone. Modification of the interfacial energies of the domains by adsorption of the aromatic molecules leads to a non-monotonic behaviour of the mean aggregate size, and a corresponding non-monotonic behaviour of the reduced viscosity of the polysoap solutions.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"14 1","pages":"903-911"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74802305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Various extensions of Onsager theory based on the second virial approximation are constructed in order to describe nematic P-phases in ribbon polymer solutions. If the average coil shape is anisotropic and the concentration is not too high, the coils can be considered as anisotropic solid objects and an ordinary expansion over the coil concentration can be performed. This first approach can be applied to study pancake nematic ordering. At higher concentrations and when the polymer chains are rather long, the polymer solution can be considered as a solution of short fragments connected into chains with a particular statistics reflecting the polymer structure with two rigidities: a similar virial expansion can be constructed. This last approach allows the consideration of the various symmetries of the nematic phases simultaneously. We also take into account the correlation correction to the mean field result which provides an essential additional angular dependence to the interaction free energy. Scaling arguments are applied in the case where the intra-coil correlations are very strong, or if the coils interact as opaque objects. The methods developed here will be used in further publications to study liquid crystalline ordering in solutions of ribbon chains.
{"title":"Highly Anisotropic Rigidity of \"Ribbon-Like\" Polymers: II. Nematic Phases in Systems between Two and Three Dimensions","authors":"I. Nyrkova, A. Semenov, J. Joanny","doi":"10.1051/JP2:1997158","DOIUrl":"https://doi.org/10.1051/JP2:1997158","url":null,"abstract":"Various extensions of Onsager theory based on the second virial approximation are constructed in order to describe nematic P-phases in ribbon polymer solutions. If the average coil shape is anisotropic and the concentration is not too high, the coils can be considered as anisotropic solid objects and an ordinary expansion over the coil concentration can be performed. This first approach can be applied to study pancake nematic ordering. At higher concentrations and when the polymer chains are rather long, the polymer solution can be considered as a solution of short fragments connected into chains with a particular statistics reflecting the polymer structure with two rigidities: a similar virial expansion can be constructed. This last approach allows the consideration of the various symmetries of the nematic phases simultaneously. We also take into account the correlation correction to the mean field result which provides an essential additional angular dependence to the interaction free energy. Scaling arguments are applied in the case where the intra-coil correlations are very strong, or if the coils interact as opaque objects. The methods developed here will be used in further publications to study liquid crystalline ordering in solutions of ribbon chains.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"51 1","pages":"825-846"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83187182","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We calculate the contribution, l pA , to the persistence length arising from charge fluctuations of an intrinsically stiff polyampholyte (PA) chain. The interaction between charges along the PA backbone is taken to be given by the Debye-Huckel potential. When the charges along the chain are uncorrelated the contribution to l pA comes from two sources. One of them is due to the overall charge on the PA chain for which the contribution to l pA OC K -2 where K -1 is the Debye screening length. Surprisingly the contribution to l pA from charge fluctuations (δσ) 2 , namely due to the polyampholyte effect, is proportional to -(δσ) 4 k -1 so that there is a reduction in the total persistence length when PA chain is overall neutral. We also show that the shape of a PA chain is cylindrical with length l p = l 0 + l pA with l 0 being the bare persistence length. The diameter of an overall neutral chain can become of the order of a monomer size which is considerably smaller than that of the corresponding polyelectrolyte. As a consequence, we argue that the interaction between two neutral stiff polyampholyte chains is attractive. The implication of the effective attractive interaction is that a dilute dispersion of neutral polyampholyte PA chains would phase separate into dense (with possible nematic order) and a rare phase. When correlations between the charges are included one gets a polyelectrolyte like behavior with l pA α k -2 even when the chain is neutral. If the range of correlation, λ, is large compared to the screening length (usually difficult to obtain in experiments) there is a large negative contribution to l pA which scales as l pA α -(δσ) 4 λ/k 2 where in is the Bjerrum length.
我们计算了固有刚性聚两性聚合物(pA)链的电荷波动对持续长度的贡献。沿PA主干电荷之间的相互作用被认为是由德拜-哈克势给出的。当链上的电荷不相关时，对l - pA的贡献来自两个来源。其中之一是由于PA链上的总电荷对l PA OC K -2的贡献其中K -1是德拜筛选长度。令人惊讶的是，由于多两性电解质效应，电荷波动(δσ) 2对l pA的贡献与-(δσ) 4 k -1成正比，因此当pA链整体中性时，总持续长度会减少。我们还证明了PA链的形状为圆柱形，长度为lp = l0 + lpa, l0为裸持久性长度。整体中性链的直径可以变成单体大小的数量级，这比相应的聚电解质的直径要小得多。因此，我们认为两个中性的刚性聚两性聚合物链之间的相互作用是有吸引力的。有效吸引相互作用的含义是，中性多两性聚合物链的稀分散将相分离成密集相(可能有向列序)和稀有相。当包括电荷之间的相关性时，即使链是中性的，也会得到与l pA α k -2类似的聚电解质行为。如果与筛选长度(通常在实验中难以获得)相比，相关范围λ较大，则对l pA的负贡献很大，其尺度为l pA α -(δσ) 4 λ/k 2，其中in为比鲁姆长度。
{"title":"Persistence Length of Intrinsically Stiff Polyampholyte Chains","authors":"B. Ha, D. Thirumalai","doi":"10.1051/JP2:1997160","DOIUrl":"https://doi.org/10.1051/JP2:1997160","url":null,"abstract":"We calculate the contribution, l pA , to the persistence length arising from charge fluctuations of an intrinsically stiff polyampholyte (PA) chain. The interaction between charges along the PA backbone is taken to be given by the Debye-Huckel potential. When the charges along the chain are uncorrelated the contribution to l pA comes from two sources. One of them is due to the overall charge on the PA chain for which the contribution to l pA OC K -2 where K -1 is the Debye screening length. Surprisingly the contribution to l pA from charge fluctuations (δσ) 2 , namely due to the polyampholyte effect, is proportional to -(δσ) 4 k -1 so that there is a reduction in the total persistence length when PA chain is overall neutral. We also show that the shape of a PA chain is cylindrical with length l p = l 0 + l pA with l 0 being the bare persistence length. The diameter of an overall neutral chain can become of the order of a monomer size which is considerably smaller than that of the corresponding polyelectrolyte. As a consequence, we argue that the interaction between two neutral stiff polyampholyte chains is attractive. The implication of the effective attractive interaction is that a dilute dispersion of neutral polyampholyte PA chains would phase separate into dense (with possible nematic order) and a rare phase. When correlations between the charges are included one gets a polyelectrolyte like behavior with l pA α k -2 even when the chain is neutral. If the range of correlation, λ, is large compared to the screening length (usually difficult to obtain in experiments) there is a large negative contribution to l pA which scales as l pA α -(δσ) 4 λ/k 2 where in is the Bjerrum length.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"32 1","pages":"887-902"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84918885","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nous etudions experimentalement, par diffusion quasi-elastique de la lumiere, les proprietes dynamiques de phases lamellaires et eponge tres diluees. Les dimensions structurales - periode smectique en phase lamellaire, taille caracteristique de la cellule en phase eponge - peuvent etre accrues de facon continue, par adjonction de solvant, jusqu'a atteindre des echelles de plusieurs milliers d'angstroms, c'est-a-dire comparables a la longueur d'onde de la lumiere. Avec des echantillons de dilution moyenne nous observons le comportement hydrodynamique habituel : relaxation temporelle mono-exponentielle et loi de puissance en q 2 dans l'espace reciproque. Aux dilutions plus elevees, le comportement n'est plus hydrodynamique : une loi de puissance en q 3 est observee en phase lamellaire comme en phase eponge ; la relaxation temporelle suit une loi en exponentielle etiree, avec un exposant universel pour les phases lamellaires non orientees et les phases eponge. Le mode d'ondulation est identifie, dans sa limite hydrodynamique et au-dela, a partir de nos donnees sur les phases lamellaires orientees ce qui donne lieu a une mesure du module k d'elasticite de courbure de la bicouche. Nous proposons une interpretation de nos donnees en phase eponge conduisant egalement a une estimation de k.
{"title":"Quasi-elastic light scattering study of highly swollen lamellar and sponge phases","authors":"É. Freyssingeas, D. Roux, F. Nallet","doi":"10.1051/JP2:1997162","DOIUrl":"https://doi.org/10.1051/JP2:1997162","url":null,"abstract":"Nous etudions experimentalement, par diffusion quasi-elastique de la lumiere, les proprietes dynamiques de phases lamellaires et eponge tres diluees. Les dimensions structurales - periode smectique en phase lamellaire, taille caracteristique de la cellule en phase eponge - peuvent etre accrues de facon continue, par adjonction de solvant, jusqu'a atteindre des echelles de plusieurs milliers d'angstroms, c'est-a-dire comparables a la longueur d'onde de la lumiere. Avec des echantillons de dilution moyenne nous observons le comportement hydrodynamique habituel : relaxation temporelle mono-exponentielle et loi de puissance en q 2 dans l'espace reciproque. Aux dilutions plus elevees, le comportement n'est plus hydrodynamique : une loi de puissance en q 3 est observee en phase lamellaire comme en phase eponge ; la relaxation temporelle suit une loi en exponentielle etiree, avec un exposant universel pour les phases lamellaires non orientees et les phases eponge. Le mode d'ondulation est identifie, dans sa limite hydrodynamique et au-dela, a partir de nos donnees sur les phases lamellaires orientees ce qui donne lieu a une mesure du module k d'elasticite de courbure de la bicouche. Nous proposons une interpretation de nos donnees en phase eponge conduisant egalement a une estimation de k.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"30 1","pages":"913-929"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76560887","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We calculate steady state properties of linear (wormlike) micelles modeled as flexible bead-spring chains from both microscopic and mesoscopic models. The latter model is based on an expression for the free energy of Gaussian chains, modified by a term which takes into account a finite scission energy in order to describe micelles, or breakable polymer chains. In equilibrium, the length distribution then depends on two parameters, namely the micellar concentration and the scission energy. Results of this approach are compared both with previous mesoscopic descriptions and Molecular Dynamics (MD) computer simulation results of the FENE-C model of linear micellar solutions (Phys. Rev. E 53 (1995) 2531). The mesoscopic model is extended to describe flow situations. Implications are discussed and compared with NonEquilibrium MD (NEMD) computer simulation results for the length distribution and flow alignment of linear micelles as well as the corresponding rheological behavior. For the case of steady shear flow both models do predict a decrease of the average micellar size with increasing shear rate.
{"title":"On the Shape and Rheology of Linear Micelles in Dilute Solutions","authors":"W. Carl, R. Makhloufi, M. Kröger","doi":"10.1051/JP2:1997163","DOIUrl":"https://doi.org/10.1051/JP2:1997163","url":null,"abstract":"We calculate steady state properties of linear (wormlike) micelles modeled as flexible bead-spring chains from both microscopic and mesoscopic models. The latter model is based on an expression for the free energy of Gaussian chains, modified by a term which takes into account a finite scission energy in order to describe micelles, or breakable polymer chains. In equilibrium, the length distribution then depends on two parameters, namely the micellar concentration and the scission energy. Results of this approach are compared both with previous mesoscopic descriptions and Molecular Dynamics (MD) computer simulation results of the FENE-C model of linear micellar solutions (Phys. Rev. E 53 (1995) 2531). The mesoscopic model is extended to describe flow situations. Implications are discussed and compared with NonEquilibrium MD (NEMD) computer simulation results for the length distribution and flow alignment of linear micelles as well as the corresponding rheological behavior. For the case of steady shear flow both models do predict a decrease of the average micellar size with increasing shear rate.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"27 1","pages":"931-946"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89368841","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lyotropic mixtures of rodlike and flexible polymers are studied. The rodlike polymer is modelled by a hard rod and the flexible polymer by a self-avoiding walk. The interaction between rodlike and flexible polymers is studied and a tendency for this interaction to force demixing is found. Diameters of the rod which are much larger than the diameter of the segments of the flexible polymer but much smaller than its radius of gyration are considered because of their relevance to mixtures of helical biopolymers and flexible polymers.
{"title":"Phase Behaviour of Athermal Mixtures of Rigid-Rod and Flexible Polymers","authors":"R. Sear","doi":"10.1051/JP2:1997107","DOIUrl":"https://doi.org/10.1051/JP2:1997107","url":null,"abstract":"Lyotropic mixtures of rodlike and flexible polymers are studied. The rodlike polymer is modelled by a hard rod and the flexible polymer by a self-avoiding walk. The interaction between rodlike and flexible polymers is studied and a tendency for this interaction to force demixing is found. Diameters of the rod which are much larger than the diameter of the segments of the flexible polymer but much smaller than its radius of gyration are considered because of their relevance to mixtures of helical biopolymers and flexible polymers.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"10 1","pages":"877-886"},"PeriodicalIF":0.0,"publicationDate":"1997-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74398437","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this paper we use a simple normal form approach of scale invariant fields to investigate scaling laws of passive scalars in turbulence. The coupling equations for velocity and passive scalar moments are scale covariant. Their solution shows that passive scalars in turbulence do not generically follow a general scaling observed for velocity field because of coupling effects.
{"title":"About generalized scaling for passive scalars in fully developed turbulence","authors":"G. He, B. Dubrulle","doi":"10.1051/JP2:1997100","DOIUrl":"https://doi.org/10.1051/JP2:1997100","url":null,"abstract":"In this paper we use a simple normal form approach of scale invariant fields to investigate scaling laws of passive scalars in turbulence. The coupling equations for velocity and passive scalar moments are scale covariant. Their solution shows that passive scalars in turbulence do not generically follow a general scaling observed for velocity field because of coupling effects.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"1 1","pages":"793-800"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91386745","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We study multiple light scattering in ordered nematic liquid crystals from long- range dielectric fluctuations. The mass operator is calculated in the first Born approximation of Dyson's equation for the average amplitude. Ne~v results are found concerning the spectral function. In addition, the average intensity is obtained numerically using a Monte-Carlo simula- tion. We simulated the anisotropic shape of the coherent backscattering cone~ the time-of-flight distribution functions and the polarization in the diffusive regime. In this article we present a vector treatment of the radiative transfer in these materials, which takes polarization correctly into account. The average field amplitude is obtained ana- lytically solving Dyson's equation while a numerical simulation has been employed to determine the average intensity. The latter approach corresponds to the solution of the Bethe-Salpeter equation using Boltzmann~s approximation, without relying upon the diffusion approximation.
{"title":"Multiple Light Scattering in Ordered Nematic Liquid Crystals","authors":"A. Heiderich, R. Maynard, B. Tiggelen","doi":"10.1051/JP2:1997104","DOIUrl":"https://doi.org/10.1051/JP2:1997104","url":null,"abstract":"We study multiple light scattering in ordered nematic liquid crystals from long- range dielectric fluctuations. The mass operator is calculated in the first Born approximation of Dyson's equation for the average amplitude. Ne~v results are found concerning the spectral function. In addition, the average intensity is obtained numerically using a Monte-Carlo simula- tion. We simulated the anisotropic shape of the coherent backscattering cone~ the time-of-flight distribution functions and the polarization in the diffusive regime. In this article we present a vector treatment of the radiative transfer in these materials, which takes polarization correctly into account. The average field amplitude is obtained ana- lytically solving Dyson's equation while a numerical simulation has been employed to determine the average intensity. The latter approach corresponds to the solution of the Bethe-Salpeter equation using Boltzmann~s approximation, without relying upon the diffusion approximation.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"43 1","pages":"765-792"},"PeriodicalIF":0.0,"publicationDate":"1997-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72676830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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