We review the current state of knowledge of phase separation and phase equilibria in porous materials. Our emphasis is on fundamental studies of simple fluids (composed of small, neutral molecules) and well-characterized materials. While theoretical and molecular simulation studies are stressed, we also survey experimental investigations that are fundamental in nature. Following a brief survey of the most useful theoretical and simulation methods, we describe the nature of gas‐liquid (capillary condensation), layering, liquid‐liquid and freezing/melting transitions. In each case studies for simple pore geometries, and also more complex ones where available, are discussed. While a reasonably good understanding is available for phase equilibria of pure adsorbates in simple pore geometries, there is a need to extend the models to more complex pore geometries that include effects of chemical and geometrical heterogeneity and connectivity. In addition, with the exception of liquid‐liquid equilibria, little work has been done so far on phase separation for mixtures in porous media.

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Phase separation in confined systems

Advanced Mathematical Methods for Scientists and Engineers

Aspects of Scientific Explanation: and Other Essays in the Philosophy of Science

We present a review of experimental, theoretical, and molecular simulation studies of confinement effects on freezing and melting We consider both simple and more complex adsorbates that are confined in various environments (slit or cylindrical pores and also disordered porous materials) The most commonly used molecular simulation, theoretical and experimental methods are first presented We also provide a brief description of the most widely used porous materials The current state of knowledge on the effects of confinement on structure and freezing temperature, and the appearance of new surface-driven and confinement-driven phases are then discussed We also address how confinement affects the glass transition

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Effects of confinement on freezing and melting.

With the maturation of the information display field, liquid-crystal materials research is undergoing a modern-day renaissance. Devices and configurations based on liquid-crystal materials are being developed for spectroscopy, imaging and microscopy, leading to new techniques for optically probing biological systems. Biosensors fabricated with liquid-crystal materials can allow label-free observations of biological phenomena. Liquid-crystal polymers are starting to be used in biomimicking colour-producing structures, lenses and muscle-like actuators. New areas of application in the realms of biology and medicine are stimulating innovation in basic and applied research into these materials.

Liquid-crystal materials find a new order in biomedical applications.

Autocorrelation function g2() and intensity (I) of the depolarized scattered light were obtained at the study of a dynamic light scattering from the composite liquid crystal (LC) material, consisting of porous polyethylenterephthalate (PET) film filled with oсtylcyanobiphenyl (8CB). The simultaneous analysis of these parameters made possible to extract the temperatures TIN and TNA of the isotropic liquid – nematic (N–I) and nematic – smectic A (N-SmA) phase transitions in LC samples confined into cylindrical pores of diameters in the range of 0.02 ... 2 μm. The dependences of TIN and TNA on the pore diameter were obtained and compared with the theoretical predictions. It was shown that simultaneous investigations of dynamic and static light scattering can be considered as a perspective approach for a study of phase transitions in LCs at strong confinement, which is typical for composite LC materials.

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Dynamic and static light scattering at phase transitions in liquid crystal confined into porous polymer film

Music can be viewed as a structure formed by notes. Different structures in music have potential to yield enormously rich diversity of different melodies. Music is a typical example where a structure defines a property. Similar concepts could be also exploited in education, in presented case in nano-sciences, which are typical representatives of soft materials the structure of which can be strongly manipulated with local geometry and presence of appropriate nanoparticles. The objects of study, named also LC shells, will be exploited as basic unit elements for future soft colloidal crystals. A different arrangement of colloids within the crystal would result in different physical properties in a similar way as different packing of atoms results in different crystals made of real atoms. In presented research will be demonstrated, how relevant basic mechanisms in thin films of nematic liquid crystals could be explained in a classroom and used as a case study, also for explanation of many other physical properties. This research topic is still in its infancy. At this stage only various defect structures in relatively simple geometries (spherical and elliptical) will be analyzed. There is a need to find simple ways to control sensitively the valence of LC shells and in particular to develop strategies to assemble them in crystal structures of desired symmetry. This would allow tailoring specific optical dispersion relations or other physical property of interest and make new ways to teach different physical properties on the "music" based approach.

Interplay between art and science in education

The past decade has witnessed an increased interest in the study of mixtures [1–3] of various soft materials and nanoparticles A characteristic feature of a nanoparticle is that at least one of its dimensions is limited to between 1 and 100 nm It is of interest to find combinations where each component introduces a qualitatively different behavior into the system Such systems are expected to play an important role in the emerging field of nanotechnology and also in composites with extraordinary material properties

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Mixtures Composed of Liquid Crystals and Nanoparticles

The Real Estate Fund of Pension and Disability Insurance (Nepremicninski Sklad) in Slovenia, founded in1997 is the owner of 3255 properties in 116 locations throughout the country and is intended for solving housing issues of pensioners of 65 years or older and other elderly persons who are allowed independently to live. The lease contracts are concluded for an indefinite period of time. The aim and vision of the Fund is to improve the quality of life for the elderly tenants by adapting the living environment, the flats and surroundings according to the physical needs of aging tenants. Homes for seniors often have low light levels and poor light spectrum caused by fluorescent or incandescent lighting. Demographic changes in most European countries show rising average life expectancy which means that the number of people with weak visual capacity or visual impairment is increasing. Equally the risks of injuries due to poor lighting conditions are increasing, e.g. missing a step resulting in a hip joint fracture. Better lighting conditions are of critical importance for aging population, as stated also in the recently published CIE227:2017. To facilitate safe environment for the elderly, the Fund in 2013 initiated a lighting research study that should provide facts and evidence for a lighting standard for their own premises.

Senior Living - Lighting, Circadian Rhythm and Dementia I

We demonstrated topological-defect driven membrane fission mechanism using a simple phenomenological model. We modeled membranes as effectively two-dimensional systems possessing in-plane ordering. Membrane configurations were described in terms of tensor orientational order parameter and curvature tensor. For demonstrative purpose we considered only membranes exhibiting spherical topology with axial and inversion symmetry. Using Effective Topological Charge Cancellation mechanism we showed that topological defects tend to assemble in regions exhibiting relatively strong Gaussian curvature. In particular, necklike membrane parts exhibit negative Gaussian curvature, which attract topological defects bearing negative topological charge. In geometries of our interest these defects can be formed via {defect, antidefect} depinning mechanism. The assembled defects, localized near the neck, give rise to relatively strong fluctuations at microscopic level, promoting membrane fission.

Samo Kralj

Papers

Dynamic and static light scattering at phase transitions in liquid crystal confined into porous polymer film

Interplay between art and science in education

Mixtures Composed of Liquid Crystals and Nanoparticles

Senior Living - Lighting, Circadian Rhythm and Dementia I

Topological Defect Driven Membrane Fission