Higroskoopne

Higroskoopne, or hygroscopic, describes the property of a substance to attract and hold water molecules from the surrounding environment, typically from humid air. This behavior occurs through adsorption on surfaces and/or absorption into the material's interior, and it depends on environmental conditions such as relative humidity and temperature.

Not all hygroscopic materials behave the same way. Some simply adsorb moisture up to a stable equilibrium, while others can absorb enough water to dissolve or deliquesce. The amount of moisture a material contains at a given temperature and humidity is called its equilibrium moisture content, and it is commonly described by sorption isotherms. As humidity rises, hygroscopic materials generally take up more water, which can alter their physical and chemical properties.

Common hygroscopic substances include salts (such as sodium chloride), sugars, wood and paper products, textiles, many polymers, and various foods. Because of their moisture sensitivity, hygroscopic materials require careful storage and packaging to control moisture ingress and prevent quality loss, clumping, or degradation. Desiccants used in packaging are deliberately hygroscopic to maintain low humidity in closed spaces.

In practical applications, hygroscopicity influences product design and processing. In pharmaceuticals and foods, moisture content affects stability and shelf life; in construction and wood products, it affects dimensional stability and mechanical strength. Measurement of hygroscopic behavior often involves determining the material’s moisture content at specific humidity and temperature, using oven-drying methods, gravimetric analysis, or dynamic vapor sorption techniques.