The present understanding of how dipolar forces affect the structure and phase behaviour classical fluids is reviewed. We focus mainly on apparent absence a liquid-vapour transition for strongly polar spherical particles, discuss same can be recovered. By concentrating theoretical simulation studies simple models, roles interplay Van der Waals interactions molecular shape clearly discerned. Connection made with experimental work ferrofluids. Finally, we computational challenges that lie ahead.

We propose a simple statistical mechanical theory for strongly dipolar fluid at low densities, based on the analogy between polymer chain and formed by polar particles. The general methods developed in of semiflexible polymers enable one to obtain expressions energy conformational entropy long dipole chain. then consider equilibrium chains different lengths derive expression free as functional length distribution. Both steric interactions are shown be weak result rarefied spheres resembles...

We introduce a microscopic model for particles with dissimilar patches which displays an unconventional "pinched" phase diagram, similar to the one predicted by Tlusty and Safran in context of dipolar fluids [Science 290, 1328 (2000)]. The model-based on two types patch interactions, account, respectively, chaining branching self-assembled networks-is studied both numerically via Monte Carlo simulations theoretically first-order perturbation theory. dense is rich junctions, while less-dense...

Abstract We consider a fluid of hard boomerangs, each composed two spherocylinders joined at their ends an angle ψ. The resulting particle is nonconvex and biaxial. occurence nematic order in such system has been investigated using Straley's theory, which simplificaton Onsager's second-virial treatment long rods, by bifurcation analysis. excluded volume boomerangs approximated the sum volumes pairs constituent spherocylinders, angle-dependent coefficient replaced low-order interpolating...

Helically twisted fibers can be produced by electrospinning liquid-crystalline cellulose solutions. Fiber topographies are studied atomic force microscopy, scanning electron microscopy (see figure) and polarized optical microscopy. The have a nearly universal pitch-to-diameter ratio comprise both right- left-handed helices.

We study a model consisting of particles with dissimilar bonding sites (“patches”), which exhibits self-assembly into chains connected by Y-junctions, and investigate its phase behaviour both simulations theory. show that, as the energy cost εj forming Y-junctions increases, extent liquid-vapour coexistence region at lower temperatures densities is reduced. The diagram thus acquires characteristic “pinched” shape in liquid branch density decreases temperature lowered. To our knowledge, this...

The authors have studied the interfacial properties of a model dipolar fluid using generalization density functional mean-field approximation. consists in weighting configurations average perturbative part energy by low-density approximation radial distribution function. This leads to bulk phase diagram which depends explicitly on strength multipole moments, contrast with results simpler version theory. calculated surface tension and density-orientational profile are fair agreement computer...

We have investigated the phase behavior of ferromagnetic Heisenberg fluid using two versions density-functional theory, viz., mean-field and modified approximations. In latter, configurations in average perturbative part energy are weighted by zero-density approximation pair distribution function. This is known to yield an improved description diagram dipolar fluids. Both theories predict, addition isotropic liquid vapor phases, a ferromagnetically ordered at moderate high (fluid) densities....

We calculate the equilibrium thermodynamic properties, percolation threshold, and cluster distribution functions for a model of associating colloids, which consists hard spherical particles having on their surfaces three short-ranged attractive sites (sticky spots) two different types, A B. The properties are calculated using Wertheim’s perturbation theory fluids. This also allows us to find onset self-assembly, can be quantified by maxima specific heat at constant volume. threshold is...

We describe a novel, low-cost and low-tech method for the fabrication of elastomeric Janus particles with diameters ranging from micrometers to millimeters. This consists UV-irradiating soft urethane/urea elastomer spheres, which are then extracted in toluene dried. The spheres thus composed single material: no coating or film deposition steps required. Furthermore, whole procedure is carried out at ambient temperature pressure. Long, labyrinthine corrugations ("wrinkles") appear on...

We have generalized earlier work on anchoring of nematic liquid crystals by Sullivan, and Sluckin Poniewierski, in order to study transitions which may occur binary mixtures as a function composition. Microscopic expressions been obtained for the energy (i) crystal contact with solid aligning surface; (ii) an immiscible isotropic medium; (iii) mixture surface. For (iii), possible phase diagrams angle versus dopant concentration calculated using simple model. These exhibit some interesting...

We use a simple model of associating fluids which consists spherical particles having hard-core repulsion, complemented by three short-ranged attractive sites on the surface (sticky spots). Two spots are type $A$ and one is $B$; bonding interactions between each pair have strengths ${ϵ}_{AA}$, ${ϵ}_{BB}$, ${ϵ}_{AB}$. The theory applied over whole range results interpreted in terms equilibrium cluster structures phases. In addition to our numerical results, we derive asymptotic expansions for...

We investigate the influence of strong directional, or bonding, interactions on phase diagram complex fluids, and in particular liquid–vapour critical point. To this end we revisit a simple model theory for associating fluids which consist spherical particles having hard-core repulsion, complemented by three short-ranged attractive sites surface (sticky spots). Two spots are type A one is B; between each pair have strengths , . The applied over whole range bonding results interpreted terms...

The structure of a fluid hard Gaussian overlap particles elongation κ = 5, confined between two walls, has been calculated from density-functional theory and Monte Carlo simulations. By using the exact expression for excluded volume kernel (Velasco E Mederos L 1998 J. Chem. Phys. 109 2361) solving appropriate Euler-Lagrange equation entirely numerically, we have able to extend our theoretical predictions into nematic phase, which had up till now remained relatively unexplored due high...

We have evaluated the bulk and surface elastic constants of a nematic liquid crystal composed Gay-Berne particles, using generalization earlier theories by Poniewierski Stecki, Lipkin, Rice Mohanty. The ratios between been plotted as function temperature at nematic-isotropic coexistence. In particular, sign K 13 (splay-bend) constant has shown to depend sensitively on details intermolecular potential. Results contrasted with those obtained from different theory.

Abstract We have used Landau–de Gennes theory to study anchoring and transitions at the interface between a nematic liquid crystal smooth solid substrate. In contrast earlier work by Sen Sullivan, we allow for spatially varying tilt angle solve Euler–Lagrange equations requiring that order parameters be uniform far from wall. found temperature-driven akin those observed experimentally can obtained either as result of change in surface parameter or due competition ordering effects nascent...

We show that suspended nano and microfibres electrospun from liquid crystalline cellulosic solutions will curl into spirals if they are supported at just one end, or, both ends, twist a helix of handedness over half its length the opposite other half, two halves being connected by short straight section. This latter phenomenon, known as perversion, is consequence intrinsic curvature fibres topological conservation law. Furthermore, agreement between theory experiment can only be achieved...

The effect of large amplitude oscillatory shear on two-dimensional stripe patterns formed by block copolymers was investigated using cell dynamics simulations. A global orientational order parameter S and a correlation function for normals $G(\mathbf{r}\ensuremath{-}{\mathbf{r}}^{\ensuremath{'}})$ were used to characterize the degree orientation under shear. kinetics alignment, quantified S, at various quench conditions studied as strain amplitude, frequency, temperature. mechanisms...

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInterfacial properties of mixtures molecular fluids: comparison between theory and experiment; methyl iodide + carbon tetrachloride acetonitrile tetrachloridePaulo I. C. Teixeira, Benilde S. Almeida, Margarida M. Telo da Gama, Jorge A. Rueda, Ramon G. RubioCite this: J. Phys. Chem. 1992, 96, 21, 8488–8497Publication Date (Print):October 1, 1992Publication History Published online1 May 2002Published inissue 1 October...

We generalize the Flory-Stockmayer theory of percolation to a model associating (patchy) colloids, which consists hard spherical particles, having on their surfaces $f$ short-ranged-attractive sites $m$ different types. These can form bonds between particles and thus promote self-assembly. It is shown that threshold given in terms eigenvalues $m\ifmmode\times\else\texttimes\fi{}m$ matrix, describes recursive relations for number bonded $i\text{th}$ level cluster with no loops; occurs when...

We have calculated the equilibrium shape of axially symmetric meniscus along which a spherical bubble contacts flat liquid surface by analytically integrating Young-Laplace equation in presence gravity, limit large Bond numbers. This method has advantage that it provides semianalytical expressions for key geometrical properties terms number. Results are good overall agreement with experimental data and consistent fully numerical (Surface Evolver) calculations. In particular, we able to...

We have extended our theory of anchoring transitions to take into account adsorption at the interface between a nematic–non-nematic binary mixture and solid aligning substrate. This was achieved by decoupling treating former in context Cahn wetting, while latter studied using previous theory. For ease calculation, we mapped relevant portion phase diagram onto that (isotropic) regular solution. The angle has been calculated over whole concentration range, partial wetting regime, near...