Tensiometrákkal

Tensiometrákkal, often shortened to tensiometers, are instruments used to measure surface tension or interfacial tension. Surface tension is a property of liquids that causes the surface to behave like an elastic sheet, resisting external forces. Interfacial tension refers to the tension between two immiscible liquids or between a liquid and a solid.

The principle behind most tensiometers involves measuring the force required to detach a probe from the liquid surface or to form a new surface. Common probe shapes include platinum plates (Du Noüy ring method) and platinum wires (Wilhelmy plate method). In the Du Noüy ring method, a ring is dipped into the liquid and then pulled upwards. The maximum force recorded just before the ring detaches from the surface is proportional to the surface tension. The Wilhelmy plate method measures the force exerted on a thin plate suspended from a balance as it contacts the liquid surface. The upward pull due to surface tension is balanced by the weight of the plate.

Another common method is the pendant drop method, which analyzes the shape of a drop of liquid hanging from a capillary. The shape of the drop is influenced by gravity and surface tension, and by fitting the observed profile to theoretical models, the surface tension can be calculated. Bubble pressure tensiometry involves measuring the maximum pressure required to form a bubble at the end of a capillary submerged in the liquid.

Tensiometers find applications in various fields, including chemistry, materials science, pharmaceuticals, food science, and oil and gas exploration. They are crucial for quality control, research and development, and understanding phenomena like wetting, foaming, and emulsification.