Identifying the Optimum Method for Modifying the Zinc Oxide Surface in Order to Obtain a High Deposit Degree of the Functioning Agent

The aim of this study is to identify the optimal method of surface modification of ZnO nanoparticles in order to obtain a high deposition rate of the polydimethylsiloxane (PDMS) functionalizing agent. Thus, in order to identify the optimal route, the surface of ZnO nanoparticles were functionalized by 3 methods, ultrasonic, magnetic stirring and vacuum adsorption, followed by advanced powder characterization, FTIR, SEM, EDS, DSC-TG. The FTIR analysis recorded on the surface modified ZnO powder highlights the functional groups in the PDMS, regardless of the synthesis method, which confirms that the functionalization took place. However, based on the intensity of PDMS functional groups, it can be concluded that the highest deposition rate is obtained in the case of ultrasonography, followed by the magnetic stirring and vacuum adsorption method. This different deposition rate can be attributed to the fact that ultrasonication leads to ZnO particles being broken down into smaller particles, resulting in a higher contact surface with PDMS. The SEM image obtained on the commercial ZnO powder and the ZnO / PDMS powder, highlights their extremely varied morphology and demonstrates that the modification does not influence either the shape or size of the ZnO. EDS analysis confirms that functionalization took place due to the presence of the Si element alongside the other Zn and O major elements. The DSC-TG analysis obtained on the ZnO / PDMS powder indicated an organic mass loss, from the organosilane structure, of 5.51% in the range of 365-530°C. The results obtained provide the premise that these functionalized ZnO nanoparticles in addition to antibacterial properties will improve compatibility / dispersibility in various polymeric matrices.