LAUSR

Abstract Mesoporous silica MCM-41 was prepared and decorated by polyethyleneimine (PEI) with different molecule weight before loading tea tree oil (TTO) to construct an environment-friendly antimicrobial sustained release system. The characterization results proved that the PEI was successfully introduced to pores of the mesoporous silica without destruction of the structure integrity. The strength of electrostatic interaction between PEI and MCM-41 was measured by the value of zeta potential which indicated that PEI with low molecule weigh was easier to be adsorbed by MCM-41 pores due to its low viscosity. The interaction of MCM-41 with TTO was strengthened after PEI modification. As a result, TTO/PEI600-MCM-41 performed the lowest cumulative release rate of 46.88% in 12 h due to the strongest interaction with TTO among all the samples. Kinetics study indicated that PEI constructed a new barrier for drug diffusion and volatilization through winding and swelling. The kinetic model for TTO/MCM-41 sustained release changed from first-order to Weibull model after PEI modification. What’s more, the service life of TTO in antimicrobial was also obviously prolonged after supported on mesoporous silica modified by PEI. Graphical Abstract