Kationilised

Kationilised describes substances that have undergone a modification to carry positive charges, typically by introducing cationic functional groups into a molecule or polymer. The term arises from the presence of cations (positively charged ions) and is used across chemistry, materials science, and related fields. Cationisation often aims to enhance interactions with negatively charged species or surfaces.

The modification is usually achieved by chemical reactions that attach cationic groups, such as quaternary ammonium or protonated amine groups, to the material. Examples include quaternized chitosan, which contains permanently charged ammonium groups, and polymers modified with glycidyl trimethylammonium chloride. The resulting materials may be water-soluble or swell in water, with solubility and charge density depending on pH and the degree of substitution.

Applications are diverse. In water treatment, cationic polymers act as coagulants and flocculants, helping remove suspended solids and dyes by binding to negatively charged particles. In papermaking and textiles, they function as retention aids and dyeing enhancers. Cationised polymers are also explored in agriculture as soil conditioners and in controlled-release formulations. In biomedicine and biotechnology, cationic polymers serve as antimicrobial surfaces or as vectors for delivering negatively charged biomolecules such as DNA or RNA, though their use can raise concerns about cytotoxicity and environmental impact.

Key considerations include charge density, molecular weight, and solubility, which influence performance. The effectiveness of kationilised materials depends on pH, since protonation and the stability of the cationic groups can vary with acidity.