Nonabsorbent

Nonabsorbent describes a material or surface that does not take up liquids into its bulk. In practice, a surface is nonabsorbent when liquids placed on it bead up or are repelled and do not penetrate into pores or the interior. The term is relative; a material may be nonabsorbent to water but absorbent to certain solvents. Nonabsorbency is often related to low porosity and/or hydrophobic surface chemistry.

Measurement and indicators: absorption is typically quantified as mass of liquid absorbed per unit area or weight, or via contact-angle measurements where a high contact angle (usually over 90 degrees) indicates poor wetting. Porosity, pore size, and capillary action influence absorbency. Surface treatments, coatings, and finishes can render materials nonabsorbent without changing bulk properties.

Common materials that are nonabsorbent include many plastics (polyethylene, polypropylene), glass, metals, glazed ceramics, and many coated textiles. In textiles, nonabsorbent finishes or tightly woven or nonporous fibers can resist liquid uptake, though some moisture transfer may still occur.

Applications: nonabsorbent surfaces are valued for ease of cleaning, stain resistance, and reducing liquid transfer in food service, medical devices, labware, flooring, and electronics protection.

Limitations: prolonged exposure to solvents, swelling of polymers, or high pressures can force liquids into some materials. Nonabsorbency does not equal impermeability to gases or all liquids.