Journal De Physique Ii最新文献_第2页

Structure of Polymer Chains Confined in Vycor 高分子链在Vycor中的结构

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997205

J. Lal, S. Sinha, L. Auvray

{"title":"Structure of Polymer Chains Confined in Vycor","authors":"J. Lal, S. Sinha, L. Auvray","doi":"10.1051/JP2:1997205","DOIUrl":"https://doi.org/10.1051/JP2:1997205","url":null,"abstract":"Nous observons par diffusion de neutrons aux petits angles la structure de chaines de polystyrene en solution semi-diluee confinees dans un milieu poreux modele, le Vycor. La taille des chaines en solution a l'etat libre est toujours superieure au diametre des pores, 70 A. L'utilisation d'un melange adequat de solvants et de polymeres hydrogenes et deuteres nous permet de mesurer directement le facteur de forme d'une seule chaine au milieu des autres. La penetration des chaines dans le milieu poreux est presque totale pour la concentration (Φ = 20%) et la gamme de poids moleculaire (35 000 < M w < 800 000) utilisees. Le rayon de gyration des chaines confinees est toujours inferieur au rayon de gyration des chaines libres dans la solution equivalente. Nos mesures sont en accord avec les predictions theoriques etablies par Daoud et de Gennes pour des chaines confinees dans un pore cylindrique quand les chaines sont enchevetrees et comprimees transversalement mais restent ideales a grande echelle dans la direction du cylindre a cause de l'ecrantage du volume exclus (regime dit de cigares semi-dilues). Les valeurs des coefficients de partage des chaines entre le milieu poreux et la solution libre ainsi que le comportement asymptotique des facteurs de structure montrent que le polystyrene s'adsorbe sur la surface nue du Vycor. Nous montrons que la silanisation du Vycor supprime cette adsorption.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"15 1","pages":"1597-1615"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81702253","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}

引用次数: 28

Adhesion of Latex Spheres to Giant Phospholipid Vesicles: Statics and Dynamics 乳胶球与巨型磷脂囊泡的粘附:静力学和动力学

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997208

Christian, Dietrich, Miglena, Angelova, Bernard, Pouligny

{"title":"Adhesion of Latex Spheres to Giant Phospholipid Vesicles: Statics and Dynamics","authors":"Christian, Dietrich, Miglena, Angelova, Bernard, Pouligny","doi":"10.1051/JP2:1997208","DOIUrl":"https://doi.org/10.1051/JP2:1997208","url":null,"abstract":"We studied the sequence of phenomena which occur when a solid microsphere is brought in contact with an isolated giant lipid vesicle. We used Latex beads, a few microns in diameter, which were manipulated individually by means of a long-working-distance optical trap. The evolution of the bead/vesicle system was characterized in time, from ∼ 1 ms to ∼ 100 s. In this time range, we identified different steps, namely adhesion, ingestion, expulsion and re-capture. In the adhesion step the sphere moves quickly in direction to the vesicle interior and the surface of the particle becomes wetted by lipids. We propose a simple model, based on the counter-balance between adhesion and stretching of the lipid lamella, which explains the experimental equilibrium configuration. The bead/vesicle configuration after the adhesion step pertains to partial or complete wetting, depending on the initial vesicle state. Partial wetting can be followed by a second step, which we named particle ingestion, and which leads to complete (or nearly complete) wetting of the particle surface. Ingestion is characterized by a further penetration of the particle across the vesicle contour, in concomitance with a decrease of the vesicle size. The phenomenon is attributed to the occurrence of a dynamically stabilized pore across the membrane, which allows part of the water initially inside the vesicle to flow out. Ingestion can be followed by a back and forth movement (expulsion and re-capture) of the particle. In the ultimate configuration, the solid surface is totally wetted by lipids, however with a finite contact angle between the membrane and the solid surface.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"25 1","pages":"1651-1682"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83655781","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}

引用次数: 93

Rencontres Physique-Biologie-Chimie de la montagne Sainte-Genevieve 1997 圣吉纳维耶夫山物理-生物-化学会议，1997年

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997203

F. Amblard, P. Silberzan, V. Croquette

引用次数: 0

Effect of a Strong Electric Field on the Reentrant Nematic to Smectic Ad Phase Transition 强电场对可重入向列到单晶相变的影响

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997210

G. Basappa, A. S. Covind, N. V. Madhusudana

引用次数: 8

Mechanical Properties of Freely Suspended Smectic Films 自由悬浮Smectic薄膜的力学性能

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997206

I. Kraus, C. Bahr, P. Pieranski

引用次数: 3

Characterization of Turbulence in a Closed Flow 封闭流动中湍流的表征

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997212

N. Mordant, J. Pinton, F. Chillà

引用次数: 31

Excitation Transfer Process in Penning Ionization of the CO Molecule by Helium Atoms in Singlet Metastable State 单线态亚稳态氦原子对CO分子Penning电离的激发转移过程

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/jp2:1997202

B. Lescop, M. Arfa, G. L. Coz, M. Cherid, G. Sinou, G. Fanjoux, A. Nadan, F. Tuffin

引用次数: 0

Motion of a Probe Ball in the Fluid under Centrifugal Acceleration 在离心加速度作用下测球在流体中的运动

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997211

I. Nyrkova, A. Semenov, A. Khokhlov, K. Linliu, B. Chu

{"title":"Motion of a Probe Ball in the Fluid under Centrifugal Acceleration","authors":"I. Nyrkova, A. Semenov, A. Khokhlov, K. Linliu, B. Chu","doi":"10.1051/JP2:1997211","DOIUrl":"https://doi.org/10.1051/JP2:1997211","url":null,"abstract":"The viscosity of a fluid can be measured by observing the motion of a probe sphere (or ball) in a centrifuge tube filled with this fluid. The hydrodynamic behavior of the probe ball moving in the centrifuge tube has been solved theoretically. We have got the universal relationship (for balls of a given material and size in a given tube) between the terminal ball velocity, the fluid viscosity and the centrifuge acceleration using the only adjustable parameter - the rotational friction coefficient between the ball and the tube. The rotation of the centrifuge tube in the horizontal plane induces an inertia force which is counterbalanced by the friction force acting on the ball. As a result, the ball moves along the tube with some characteristic speed, which is a measure of the viscosity of the fluid. This speed was calculated in the lubrication approximation. The gravitational acceleration causes the ball to move very close to the bottom of the centrifuge tube. In this situation, the gravity is balanced by a levitation force introduced and calculated in the present paper. The origin of this force is the formation of the bubble behind and below the moving ball. The theoretical development on the terminal velocity for the ball moving very near the bottom of the horizontal centrifuge tube is tested by using a specially designed centrifuge for two types of balls and a wide set of viscosity standards. Excellent agreement between theory and experiment suggests that we have developed a new approach to measure high viscosities of fluids at low shear rates which might be especially useful for the investigation of polymer melts.","PeriodicalId":14774,"journal":{"name":"Journal De Physique Ii","volume":"32 1","pages":"1709-1728"},"PeriodicalIF":0.0,"publicationDate":"1997-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88112623","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}

引用次数: 9

Static and Dynamic Light Scattering Near the Liquid Crystalline Blue Phase III – Isotropic Liquid Critical Point 液晶蓝相附近的静态和动态光散射III -各向同性液体临界点

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997209

U. Singh, P. Collings, C. Booth, J. Goodby

引用次数: 3

SiO Evaporated Films Topography and Nematic Liquid Crystal Orientation SiO蒸发薄膜形貌与向列液晶取向

Journal De Physique Ii Pub Date : 1997-11-01 DOI: 10.1051/JP2:1997204

M. Monkade, P. Martinot-Lagarde, G. Durand, C. Granjean

引用次数: 14