Porstorlek

Porstorlek, or pore size, is a measure of the size of voids in a material. It is a key parameter for characterizing porosity and governs how substances move into, within, and out of a solid. Pore size distribution describes how pore volumes are allocated among different sizes and is often more informative than the total porosity alone. The classification most commonly used in literature divides pores into micropores (<2 nanometers), mesopores (2–50 nanometers), and macropores (>50 nanometers). In some fields, definitions vary, and larger-scale pores such as capillary channels may be treated separately.

Pore size can be measured by several techniques. Mercury intrusion porosimetry provides porosity and pore-size distribution for many materials but requires careful handling due to high pressures. Gas adsorption methods, including BET and BJH analyses, are well suited for smaller pores. X-ray computed tomography and electron microscopy enable three-dimensional imaging of pore networks and direct visualization of connectivity. Capillary rise and liquid extrusion methods can be used for complementary data, especially in porous media like soils.

The pore size distribution has a strong impact on material behavior. It controls permeability and diffusivity in porous solids, adsorption capacity, reaction rates in catalysts, and mechanical properties such as strength and stiffness. In soils and sediments, macropores promote drainage and aeration, while micropores retain water and dissolved constituents.

Applications span ceramics, membrane technology, catalysts, energy storage, soil science, and oil and gas reservoirs, where tailored pore sizes optimize transport and storage properties.