Liquid Complexes, Liquid Crystals and Glassy States : Pharmaguideline

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Liquid Complexes, Liquid Crystals and Glassy States

Described as materials that behave like liquids and solids, in the same way, complex fluids and soft matter show both liquid and solid properties.

Liquid complexes

Described as materials that behave like liquids and solids, in the same way, complex fluids and soft matter show both liquid and solid properties.
There are four types of binary fluids: solids and liquids (solutions and suspensions of macromolecules), solids and gases (granules), liquids and gases (foams), and liquids and liquids (emulsions).

Gels, foams, granular materials, glasses, melts, and solutions made of polymer materials are examples. Such systems often exhibit clear inherencies of disorder and heterogeneity, with considerable fluctuations across a wide range of time and space scales. A theoretical analysis of complex fluids like glasses or gels is also difficult because they do not relax into equilibrium. It is common for complex systems to be characterized by a rather general model of organization: their behavior is governed by issues of self-organization (ordering) and self-disorganization (disordering), which combine to form a hierarchical adaptive structure.

A concept of complexity can also be applied to materials showing slow and nonexponential relaxation, particularly liquids and glasses that form from amorphous materials. Liquids do not all become complex when cooled. The simple two-particle interactions of three-dimensional liquids (melted metals, salts, and liquefied noble gases), as well as computer liquids such as Lennard-Jones (LJ), or softcore, crystalize rapidly on cooling.

Gels and glasses - The first time a cluster of molecules connected for the first time appears in a polymeric melt or dense solution when the molecules are sufficiently crosslinked. When the crosslinking of molecules within the fluid or sol phase is low, the molecules explore all available volumes; however, in gel or amorphous solid phase, the particles localize in random positions and do finite thermal excursions.

Liquid crystals

The cloudy liquid may have a new state of matter called liquid crystal after Otto Lehmann, an expert in crystal optics, studied it. Cathode ray tubes (CRT) were invented by Karl Braun, a German scientist. Gatterman and Nitschke were the first to produce p-azoxyanisole, the first synthetic liquid crystal, in 1890, after all the liquid crystalline substances investigated up to that time were naturally occurring. Examples are isooctane, ammonium thiocyanate, and sodium decanoate.

They are substances that exist in two quite different states of matter simultaneously. Isotropic liquids and crystallized solids are the most common states of matter. Liquid crystals are a phase formed at the intersection of two solids. They are also called molecules. When molecules are distributed randomly in an isotropic liquid, neither their position nor orientation is ordered. The arrangement of molecules or atoms varies over a long-range in a crystal, both in terms of orientation and three-dimensional position.

CRYSTAL LIQUID: it's solid or liquid?

Known as latent heat, this is the amount of heat required to induce phase transition in a crystal of transition. The difference in heat between the two phases can be measured using this heat. Cholesterylmyristate possesses a latent heat of 65 calories per gram of solid to liquid crystal. The latent heat for both liquid crystals and liquids is 07 calories per gram. If liquid crystals and liquid are more similar than solids in terms of latent heat, then liquid crystals are more like liquids.

Liquid crystalline phase

Mesophases are phases that occur between solid and liquid. A change in sample order can result in the formation of these products. The crystal liquid is a fluid that has both crystal and liquid properties. If certain solvents or solids are mixed with molecules, a liquid crystalline state may result. When the compound is heated, it may take the form of a liquid crystalline state.

Characterization of liquid crystal phase

This type of crystal structure is described by the following characteristics.
  1. Structure-property relations describe the tendency of molecules or groups of molecules to exhibit translational symmetry in crystalline materials.
  2. The orientation order measures the tendency of molecules to align along the long-range axis of any given director.
  3. Bond Orientational Order: the line joining the centers of molecules directly next to one another without regular spacing along that line.
The combination of Positional Order and Orientational Order gives a crystal phase.

Different Positional order + Orientational order = LC phase

Glassy states

The state of matter of glass is neither equilibrium nor crystalline, and although it appears solid for a short period, it continuously relaxes towards the liquid state. Glass is classified as a non-conductive transparent solid, which is a class of solids. It can neither be classified as a liquid nor a solid. In solids, the atoms and molecules are usually arranged systematically, while they are highly disordered in Glassy materials. While polymer materials have a long-range order, glassy materials have some short-range order. A glassy substance does not have a specific melting point, although it slowly liquefies when heated. It can be argued that Glassy materials are composed of a haphazard selection of polyhedron molecules tethered together at their corners.

Glassy states can be easily achieved by certain materials, while others require great difficulty, and certain materials cannot be achieved at all. Though the exact mechanism behind this behavior has yet to be determined, it has been shown that the substrates that can be converted to a glassy state are highly viscous at their melting point, which makes it impossible for a finely ordered structure to form. Metal oxides are generally the most common materials that can be converted to a glassy state, but even materials such as steel can be converted if they are cooled quickly enough. By using this technique, glass is formed since the material solidifies before it has a chance to crystallize.

In differential scanning calorimetry (DSC) curves, a glass transition temperature (Tg) was measured in the melts and an abnormal endothermic peak (maximum heat capacity) observed for glassy pharmaceuticals was determined. Twenty pharmaceuticals (such as aspirin, phenobarbital, antipyrine, and so on) were found to form glass. Between 0.59 and 0.84 are the values of the ratio between Tg and melting temperature (Tm) for these pharmaceuticals.
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Ankur Choudhary is India's first professional pharmaceutical blogger, author and founder of, a widely-read pharmaceutical blog since 2008. Sign-up for the free email updates for your daily dose of pharmaceutical tips.
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