Novel Ester-bonded Gemini Quaternary Ammonium Salt with Good Antimicrobial Activity and Anti-mold Performance for Wet Blue Leather

Herein, we have developed a kind of novel ester-bonded gemini quaternary ammonium salts microbicides named QAS(n+m) for leather application, in which n and m denotes the number of −CH2 between the ester groups on the spacer, and the length of alkyl chain connected to ester groups on the hydrophobic tail chain, respectively. Results indicate that the hydrophobic tail lengths and the spacer lengths in the QAS(n+m) structures affect their antimicrobial activities very differently. QAS(4+10) was used to investigate the antimicrobial mechanism, cytotoxicity, and antimold performance for wet blue leather as it exhibits the strongest antimicrobial effect. It shows QAS(4+10) is capable of inactivating microorganisms mainly by disrupting the integrity of their cell membranes. Compared to commercial leather microbicide product 2-thiocyanomethylthiobenzothiazole (TCMTB), QAS(4+10) exhibits comparable mold resistance and lower toxicity. The present work gives positive insight into the development of novel candidate microbicides for the preservation of wet blue leather.