Kationisk

Kationisk is a term used in Scandinavian languages to describe substances that carry a positive electric charge. In chemistry, a cation is an ion with more protons than electrons, and kationisk describes molecules or polymers that contain positively charged groups such as ammonium or quaternary ammonium groups. The word contrasts with anionic (negatively charged) and with neutral species. The term is commonly applied to small inorganic cations, organic cations, and macromolecules such as cationic surfactants and cationic polymers.

In solution, kationiske species interact with negatively charged surfaces and with other ions. Their behavior is influenced by pH, ionic strength, and the nature of counterions. A key feature is their tendency to adsorb to negatively charged materials, which underpins many applications in industrial and environmental processes. Structural motifs such as quaternary ammonium groups are typical for permanent positive charge, making them stable across pH ranges.

Examples include inorganic cations like Na+, Ca2+ and ammonium; organic cations such as cetyltrimethylammonium (CTMA)+ and benzalkonium derivatives; cationic surfactants used in detergents and disinfectants; and cationic polymers such as poly(diallyldimethylammonium chloride) (PDADMAC) and various polyquaternium polymers used in cosmetics and papermaking.

Applications span water treatment, where cationic polymers aid coagulation and flocculation by neutralizing negative surfaces; papermaking and coatings, where they improve retention and finish; and personal care products, where conditioning polymers bind to negatively charged hair or fibers. Safety and environmental considerations include potential aquatic toxicity and sustainability, as well as interactions with anionic substances that can affect formulation stability and treatment processes.