Vattenabsorption

Vattenabsorption (water absorption) is the process by which a material or tissue takes up water or moisture from its surroundings. It occurs through diffusion of water into the material, capillary action in porous structures, or a combination of both. Depending on the material, absorption can involve surface adsorption, reversible swelling, or bulk uptake that changes dimensions and mechanical properties. In textiles, water absorption influences comfort, dye uptake, and drying time; in wood and concrete it affects strength, durability, and susceptibility to decay or frost damage; in foods it governs rehydration and texture.

Absorption is commonly expressed as the increase in mass after immersion in water for a defined period or as equilibrium moisture content. Tests include gravimetric methods, immersion tests, and sorption isotherms. In polymers and composites, diffusion coefficients describe the rate of uptake; in porous materials, porosity and pore size control speed and capacity. Absorption behavior can be categorized as hygroscopic (reaching moisture equilibrium with the environment) or non-hygroscopic (minimal uptake under ordinary conditions).

Factors influencing water absorption include temperature, humidity gradient, porosity and pore structure, surface chemistry (hydrophilicity versus hydrophobicity), thickness, and the presence of coatings or crosslinking. Treatments can reduce absorption by applying hydrophobic finishes or increasing density, while structural changes that increase porosity or swelling can raise uptake. Understanding vattenabsorption is important for predicting performance, durability, and handling across textiles, construction, packaging, and food processing. See also hygroscopicity, diffusion, osmosis, capillary action.