Multi-surfactant system electrostatically coupled to a cellulose nanocrystal comprising a cetrimonium chloride/fatty acid surfactant mixture

A composition comprising a multi-surfactant system on a substrate, in which the multi-surfactant system comprises:

• A) a cationic constant surfactant and
• B) a charge variable surfactant, wherein these surfactants are associated in the form of a complex in an aqueous medium, wherein;
• i) the charge variable surfactant has at least one neutral end group at one pH value of the medium and at least one anionic polar group at a different pH value of the medium;
• ii) the cationic constant surfactant has at least one cationic group that does not change charge at the one or different pH values of the aqueous medium;
• iii) the cationic constant surfactant is cetrimonium chloride;
• iv) the cationic constant surfactant and charge variable surfactant are at a molar ratio of about 1:1;
• v) the cationic constant surfactant is electrostatically coupled to an anionic surface of the substrate, thereby providing said surface with a reversible, pH-dependent surface polarity;
• and
• vi) the substrate is a cellulose nanocrystal.