Journal ArticleDOI
The effects of shape on the interaction of colloidal particles
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In this article, it was shown that colloids in general are apt to exhibit considerable deviations from Raoult's law and that crystalline phases retaining a fair proportion of solvent may separate from concentrated solutions.Abstract:
Introdzution. The shapes of colloidal particles are often reasonably compact, so that no diameter greatly exceeds the cube root of the volume of the particle. On the other hand, we know many coiloids whose particles are greatly extended into sheets (bentonite), rods (tobacco virus), or flexible chains (myosin, various Iinear polymers). In some instances, a t least, solutions of such highly anisometric particles are known to exhibit remarkably great deviations from Raoult’s law, even to the extent that an anisotropic phase may separate from a solution in which the particles themselves occupy but one or two per cent of the total volume (tobacco virus, bentonite). We shall show in what follows how such results may arise from electrostatic repulsion between highly anisometric particles. Most colloids in aqueous solution owe their stability more or less to electric charges, so that each particle will repel others before they come into actual contact, and effectively claim for itself a greater volume than what it actuaily occupies. Thus, we can understand that colloids in general are apt to exhibit considerable deviations from Raoult’s law and that crystalline phases retaining a fair proportion of solvent may separate from concentrated solutions. However, if we tentatively increase the known size of the particles by the known range of the electric forces and multiply the resulting volume by four in order to compute the effective van der Waal’s co-volume, we have not nearly enough to explain why a solution of 2 per cent tobacco virus in 0.005 normal NaCZ forms two phases.read more
Citations
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Liquid Crystalline Phase Behavior of Protein Fibers in Water: Experiments versus Theory
Jin-Mi Jung,Raffaele Mezzenga +1 more
TL;DR: New method allowing the study of the thermodynamic phase behavior of mesoscopic colloidal systems consisting of amyloid protein fibers in water, obtained by heat denaturation and aggregation of beta-lactoglobulin, a dairy protein is developed.
Journal ArticleDOI
Additive-Free MXene Liquid Crystals and Fibers
Jizhen Zhang,Simge Uzun,Shayan Seyedin,Shayan Seyedin,Shayan Seyedin,Peter A. Lynch,Bilen Akuzum,Zhiyu Wang,Si Qin,Mohamed Alhabeb,Christopher E. Shuck,Weiwei Lei,E. Caglan Kumbur,Wenrong Yang,Xungai Wang,Genevieve Dion,Joselito M. Razal,Yury Gogotsi +17 more
TL;DR: The first experimental observation of self-assembled LC phases in aqueous Ti3C2Tx MXene inks without using LC additives, binders, or stabilizing agents is reported, showing that the transition concentration from the isotropic to nematic phase is influenced by the aspect ratio of MXene flakes.
Journal ArticleDOI
Self-Assembly of Lyotropic Chromonic Liquid Crystal Sunset Yellow and Effects of Ionic Additives
Heung-Shik Park,Shin-Woong Kang,Luana Tortora,Yuriy A. Nastishin,Daniele Finotello,Satyendra Kumar,Oleg D. Lavrentovich +6 more
TL;DR: It is proposed that the aggregates of LCLCs can be more complex than simple rods and contain "stacking faults" such as junctions with a shift of neighboring molecules, 3-fold junctions, etc.
Journal ArticleDOI
Nematic–isotropic transition in polydisperse systems of infinitely thin hard platelets
Martin A. Bates,Daan Frenkel +1 more
TL;DR: In this paper, the phase behavior of model colloidal systems composed of infinitely thin hard platelets, with polydispersity in the size of the particles, was studied using semi-grand Gibbs ensemble simulations.
Journal ArticleDOI
Isotropic-nematic phase transition in suspensions of filamentous virus and the neutral polymer Dextran.
TL;DR: At high ionic strength it is found that adding polymer widens the isotropic-nematic coexistence region with polymers preferentially partitioning into the isotopic phase, while at low Ionic strength the added polymer has no effect on the phase transition.
References
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The Role of Attractive and Repulsive Forces in the Formation of Tactoids, Thixotropic Gels, Protein Crystals and Coacervates
TL;DR: In this paper, it was shown that the Coulomb attraction between the micelles and the oppositely charged ions in the solution gives an excess of attractive force which must be balanced by the dispersive action of thermal agitation and another repulsive force.