Synthesis and characterization of antibacterial compounds using montmorillonite and chlorhexidine acetate

Two series of antibacterial compounds were synthesized using montmorillonite and chlorhexidine acetate (CA) by ion-exchange reaction. The resulting samples were characterized by high-resolution thermogravimetric analysis (HRTG), Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and their antibacterial activity was assayed by halo method. In this study, the loaded amounts of CA in the resultant compounds were evaluated by the HRTG curves. CA adopts a lateral monolayer arrangement in the resulting samples with low CA loading, while a special state with partial overlapping of organic molecules is supposed for the resulting samples prepared at 1.0-4.0 CEC. After the intercalation with CA, the hydrophilic surfaces of montmorillonite are changed to hydrophobic ones, reflected by the frequency shift of the symmetric v(1(O-H)) stretching vibration from low to high. This study shows that the interlayer cations in raw montmorillonite have little influence on the structure of the resulting samples. Antibacterial activity test against E. coli demonstrates that the antibacterial activity of the resulting samples strongly depends on the content of the loaded CA and these resulting materials show a long-term antibacterial activity that can last for at least one year.