11/10/2021
By Kwok Fan Chow
The Kennedy College of Science, Department of Chemistry, invites you to attend a proposal defense by Ruogu Tang entitled “Polymeric N-halamines as Additives of Paints/Coatings for Antimicrobial and Antifouling Applications.” The defense will be held on Nov. 19 at 9 a.m. via Zoom.
The committee will be composed of Yuyu Sun (chair), Kwok-Fan Chow, James Reuther, and James Whitten. A brief abstract is provided below.
Abstract:
Biofouling is an undesirable accumulation and growth of organisms on solid surfaces in an aqueous environment. It is one of the biggest challenges in operations of vessels and oceanic instruments, leading to serious structural and functional problems. Current strategies against biofouling have various limitations and thus, new systems are needed to control biofouling and related problems.
In this study, N-halamines, a family of compounds containing oxidative halogens attached to nitrogens, were used as antifouling additives of aquatic paints. Three types of chlorine-based polymeric N-halamines, amine-based N-halamines, amide-based N-halamines, and copolymers containing both amine and amide N-halamines were synthesized and their structures were characterized by FT-IR, 1H-NMR, and UV studies.
The polymeric N-halamines were added into commercial vessel paints as additives, and the modified paints were coated on metals and plastic substrates that are commonly used in marine vessels. The N-halamine additives did not negatively affect the surface morphologies of the original paints, provided strong antibacterial and antifungal effects, and effectively prevented biofilm formation. A long-term chlorine stability study showed that the N-halamine-containing paint slowly and continuously released a small amount of free chlorine in both seawater and freshwater for more than 60 days. The effects of N-halamine structures on fouling-controlling potency and durability were discussed.
These preliminary results point to the potentials of polymeric N-halamines as a new class of antifouling agents. Based on current results, in future studies, we will focus on: (1) effects of structural characteristics on antimicrobial activities, (2) application of N-halamine products on different types of paints and coating them on different substrates, (3) algaecidal activities investigation, (4) antifouling mechanism investigation, (5) durability and rechargeability of the antifouling effects, and (6) synergistic effects of the N-halmines with other antifouling agents.
All interested students and faculty members are invited to attend.