nonporous

Nonporous refers to a material that has no interconnected pores or voids large enough to permit the passage of fluids or gases, or to have an extremely low porosity. In practice, nonporous materials form barriers to liquids and gases under typical conditions, distinguishing them from porous materials that contain void spaces that can be filled or connected to allow infiltration or flow. Porosity is the fraction of a material’s volume that consists of voids; when porosity is effectively zero, the material is considered nonporous.

The term is used across disciplines such as geology, materials science, engineering, and construction. Common nonporous materials include glass, many metals, dense ceramics, and tightly cured polymers. Some polymers can be nonporous when fully processed, while foamed or sponge-like variants are porous. Nonporous properties can be affected by surface finish, microcracks, or manufacturing defects that create pathways for limited permeation.

Measurement and interpretation vary by context. Porosity is typically quantified by methods such as porosimetry or gravimetric techniques; permeability considers how easily a material allows fluid or gas to pass through, which can be different from porosity in practice. A truly nonporous material resists absorption and penetration under standard conditions, though extreme pressures or chemical attack can alter this behavior.

Applications of nonporous materials include hermetic seals, containment vessels, laboratory surfaces, countertops, and protective coatings. They are valued for ease of cleaning, chemical resistance, and moisture barriers, but may require consideration of durability, scratch resistance, and potential crack propagation in service.