Cationicos

Cationicos, or cationics, refer to substances or species that bear a positive electric charge. In chemistry, the term encompasses both free cations (positively charged ions) and materials that have positively charged functional groups. Cationicos are contrasted with anions, which carry negative charge.

Common inorganic cations include simple ions such as sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and transition metal cations like iron in its various oxidation states. These ions play essential roles in biological processes, electrochemical systems, and environmental chemistry, influencing ionic strength, conductivity, and reaction pathways.

Organic and polymeric cations expand the category to ammonium, phosphonium, and sulfonium ions. Quaternary ammonium salts are widely used as cationic surfactants due to their persistent positive charge. In polymer chemistry, cationic polymers—such as polyethylenimine and polymers bearing diallyldimethylammonium chloride units—carry positive charges along their chains. They are employed in water treatment for flocculation and coagulation, in gene delivery as vectors, and in various coatings and personal care products.

Key properties of cationicos include strong electrostatic interactions with negatively charged species, variable hydration energies, and charge density that influences binding, solubility, and reactivity. Their behavior depends on pH, ionic strength, and the presence of counterions, which can modulate association and dissociation processes.

Applications span water treatment, cosmetics and cleaners, electrochemistry, materials science, and biomedicine. In biology and medicine, cationic species are used in delivery systems and as antimicrobial agents, but they can also pose toxicity and biocompatibility concerns that require careful handling and disposal.

See also: ions, cations, anions, surfactants, polymers.