Synthesis and applications of quaternary ammonium chitosan as additives in hair-care products

Abstract

At any conditions with pH above the isoelectric point (~3.67), the surface of hair bears a net negative charge. Therefore, positively charged ingredients can be easily coated on it. In this work, two positively charged derivatives of chitosan, N,N,N-trimethylammonium chitosan chloride (TMC) and N-[(2-hydroxyl-3-trimethylammonium)propyl]chitosan chloride (HTACC), with varying degrees of quaternization (DQ) were synthesized for use in “leave-on” conditioners. The chemical structures of the charged derivatives were verified by 1H NMR and FTIR. From in vitro cytotoxicity study by MTT assay, dependent on toxicity against HaCaT cells line was observed for HTACC. TMC (22 ) and HTACC (24 ) were used as cationic ingredients in the conditioner because of their lowest toxicity as well as synthesis costs. The prepared leave-on conditioners were able to coat on hair as evidenced by scanning electron microscopy and ATR-FTIR microspectroscopy. In addition, tests for hair’s tensile properties, texture, and wet combing were also evaluated. The prepared conditioners could increase the strength and the smooth feel of waved and straightened hairs more than did the commercial product. This study can in fact pave the way for commercial application of the positively charged chitosan compounds in hair-care industry.