Surface treatment for antibacterial applications

• Main Author: Janet, Kezia
• Other Authors: Lam Yeng Ming
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2022
• Subjects: Engineering::Materials::Material testing and characterization
• Online Access: https://hdl.handle.net/10356/159400
• Institution: Nanyang Technological University

With the ongoing pandemic, wearing masks has become a part of our daily life. Masks have played an essential role as they have become a necessary thing for us in doing varying activities. Hence, in addition to the importance of protection that the masks can provide, one should also take into consideration the comfort of users upon wearing the masks. Different research has been conducted to improve the protection for users, for instance through additional functionalities to kill viruses and bacteria, not only trapping them. Moreover, incorporating these functionalities to reusable masks is a field of interest, as currently, the usage of disposable masks has created a newly emerging issue of waste to the environment. In this study, five different solvents have been evaluated to coat PDMS, a hydrophobic agent and compatibilizer on cotton substrates. Further, cuprous oxide nanoparticles were coated on the cotton substrates to achieve antimicrobial properties. In addition to that, the concentration of PDMS was varied from 1-4% to investigate the effect on the substrates, and retention of the coating properties was investigated after washing for six hours. Characterization was done through water contact angle measurement, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscope (SEM) imaging. From the five solvents investigated, it can be concluded that tetrahydrofuran and octamethyltrisiloxane are able to create a homogeneous hydrophobic coating on the cotton substrates. Additionally, a slight increase in water contact angle upon subsequent coating of the PDMS-coated cotton substrates with Cu2O nanoparticles was determined. Furthermore, the optimal concentration of PDMS to coat the cotton substrates was selected at 1 wt%, as the water contact angle and amount of copper nanoparticles were not affected by the concentration of PDMS. Furthermore, excessive accumulation of PDMS could be observed by the formation of bridges on the cotton substrates coated with 2-4 wt% PDMS, hence it is not recommended to increase the concentration of PDMS beyond 1 wt%. PDMS and Cu2O nanoparticles-coated cotton can retain the desired properties, such as a high water contact angle value, even after washing for 6 hours, demonstrating a robust hydrophobic coating. In summary, using octamethyltrisiloxane as a solvent to dissolve PDMS for coating cotton substrates will be beneficial in creating a suitable formulation for reusable antimicrobial masks.