Porogenic

Porogenic is an adjective used in materials science to describe substances or processes that generate pores in a material, increasing its porosity. A porogen is an agent incorporated into a precursor that is later removed to leave behind a porous network. Porogenic strategies are widely used to tailor pore size, distribution, and connectivity for applications in filtration, catalysis, and biomedicine.

Porogen leaching involves dispersing solid particles (such as salt, sugar, or polymer beads) within a polymer matrix, curing the composite, and then dissolving the porogen to create interconnected pores. The resulting pore size roughly tracks the size of the porogen particles. Alternative approaches rely on phase separation: non-solvent-induced phase separation (NIPS) or thermally induced phase separation (TIPS) during polymer casting, where a porogenic liquid or solvent-rich phase forms pores upon removal or solidification. Gas foaming uses a blowing agent to create gas-filled pores; the gas is later vented or dissolved, leaving voids.

In ceramics and inorganic materials, porogenic strategies may involve incorporating removable templates or sacrificial particles to create macroporosity; carbon foams or silica monoliths can be produced with porogens that are subsequently removed via dissolution or combustion.

In biomedical engineering, porogenic scaffolds require high porosity and interconnectivity to support cell infiltration and nutrient transport. The choice of porogen and the processing conditions influence pore size distribution, mechanical properties, and biocompatibility. Challenges include ensuring complete porogen removal, avoiding residue, and maintaining sufficient strength.

Common examples include salt-leached poly(lactic-co-glycolic acid) and polyurethane foams with sugar or polymer beads; polymeric porogens may also be designed to degrade in situ, releasing pores as the scaffold ages.