didecyldimethylammonium chloride (ddac) is an antiseptic/disinfectant that is used in many biocidal applications. it causes disruption of intermolecular interactions and dissociation of lipid bilayers. it is a broad spectrum bactericidal and fungicidal and can be used as disinfectant cleaner for linen, recommended for use in hospitals, hotels and industries. it is also used in gynaecology, surgery, ophthalmology, pediatrics, ot, and for the sterilization of surgical instruments, endoscopes and surface disinfection.