Synthesis and characterization of chitosan-based 'comb-like' zwitterionic surfactants

Low-cost surfactants are of great importance for many applications. Chitosan is one of the abundant promising candidates as a raw material for low-cost surfactants. However, how to tune the molecular structure to achieve high solubility, low surface tension, and good foam stability is a great challenge. Herein, the 'comb-like' zwitterionic polymer surfactant based on chitosan by partial N-alkylation and quaternization was prepared. The experimental results demonstrate that the length and degree of substitution of the alkyl chain have a significant influence on the properties of the products. Such comb-type zwitterionic polymer surfactants have good water solubility, and the water solubility can reach up to 85 g/L. Surface tension and foam performance tests reveal that such 'comb-like' zwitterionic polymer surfactants have excellent surface activity and good foam stability, especially for the products with a degree of substitution of 20%; their surface tension can be as low as 27.1 mN/m, and the foam stability can be improved by 59.32%.

Automated summary

In this study, a comb-like zwitterionic polymer surfactant with good water solubility, low surface tension, and good foam stability was successfully prepared by modifying the molecular structure of chitosan. The results show that the length and degree of substitution of the alkyl chain have a significant influence on the properties of the surfactants.