What is the measurement of surface and interfacial tension?
Surface tension is the excess energy per unit area (force per unit length; SI unit is Nm-1). Typically mN/m (which is equivalent to dynes/ cm) is used as the unit for surface and interfacial tension.
What is surface tension and its applications?
Surface tension is the tendency of liquid surfaces at rest to shrink into the minimum surface area possible. Surface tension is what allows objects with a higher density than water such as razor blades and insects (e.g. water striders) to float on a water surface without becoming even partly submerged.
How is interfacial tension measured?
Interfacial tension can also be measured by a force tensiometer. This instrument measures the forces exerted on the probe which is positioned at the liquid/gas interface. Subsequently, the force measured by the balance as the probe interacts with the surface of the liquid can be used to calculate the tension.
Why interfacial tensions are less than surface tension?
It comes down to the relative strength of the cohesive forces in the two phases. In the gas phase the cohesive forces are substantially smaller in magnitude that those in the liquid phase. Hence surface tension is greater than interfacial tension.
How surface and interfacial tension affects the performance of pharmaceutical compounds?
Surface and interfacial tension affects the performance of pharmaceutical compounds. Surface and interfacial tension plays a crucial role in many pharmaceutical processes from tablet coating to drug solubility and stability. Interfacial properties have also a clear impact on the solubility of the drug.
What is the measurement of surface tension?
As a measure of work per unit area or force per wetted length, surface tension has the unit mN/m and is designated by the symbol σ (lower case sigma). If the phase is solid, the equivalent term surface free energy is normally used. If the adjacent phase is a liquid or a solid, reference is made to interfacial tension.
Why is interfacial tension important?
Significance. The interfacial tension plays an important role in many processes and phenomena where different phases touch one another: Emulsions and emulsifiability: The interfacial tension affects the emulsifiability and the tendency for the phases to separate.
What are the application of interfacial phenomena in the practice of pharmacy?
Interfacial phenomena affect drug delivery systems. For example, solubilization and dispersion of drugs, suspension or emulsion stability, and adsorption of drugs on different substrates are all affected by the interfacial properties of drugs and their environment.
What is difference between surface and interface?
Common Sense: A surface is the shell of a macroscopic object (the inside) in contact with its environment (the outside world). An interface is the boundary between two phases. The surface of an object determines its optical appearance, stickiness, wetting behavior, frictional behavior, and chemical reactivity, e.g.
What are the applications of surfactants?
Surfactants play an important role as cleaning, wetting, dispersing, emulsifying, foaming and anti-foaming agents in many practical applications and products, including detergents, fabric softeners, motor oils, emulsions, soaps, paints, adhesives, inks, anti-fogs, ski waxes, snowboard wax, deinking of recycled papers.
How to measure surface and interfacial tension?
Techniques to measure surface and interfacial tension are separated here into two main categories: force tensiometry where the force the surface imparts on a probe is directly measured; and optical tensiometry where the profile of a drop or bubble extracted from an image is fit to a theoretical equation.
What is the origin of interfacial tension?
The highest surface tensions The origins of interfacial tension are analogous. In terfacial tension is a material property of a the two fluid phases. The result is an interfacial energy per area that acts to resist the creation interface. Fluids between which no interfacial tension arises are said to be miscible.
How do you measure surface tension at a liquid liquid interface?
In this method a thin plate (often made of platinum or glass) is used to measure equilibrium surface or interfacial tension at air-liquid or liquid-liquid interfaces. The plate is oriented perpendicularly to the interface and the force exerted on it is measured.
What is terfacial tension?
In terfacial tension is a material property of a the two fluid phases. The result is an interfacial energy per area that acts to resist the creation interface. Fluids between which no interfacial tension arises are said to be miscible. F or example,