Studies of the association of chitosan and alkylated chitosan with oppositely charged sodium dodecyl sulfate

Cationic biopolymer chitosan has many applications in food, cosmetic and pharmaceutical industries. Grafting alkylated chains on its backbone can hydrophobically modify this water-soluble polymer.This paper concerns unmodified chitosan, alkylated chitosan and their interactions with a model anionic surfactant, sodium dodecyl sulfate (SDS). The solvent is pH 4 acetic acid solution. The purpose of this study is to highlight the hydrophobicity brought by the alkylated chains by comparing surface tension measurements and rheological properties of hydrophobically modified polymer (HMP) and chitosan solutions at 25 °C.Interactions of chitosan and HMP with surfactant have also been investigated giving information about surface activity and electrical conductivity of such systems. It results that alkylated chitosan/SDS system is more surface active than chitosan/SDS and it offers new potential applications in pharmaceutical and cosmetic fields because of the formation of amphiphilic complexes.