Catherine Bishop - Canterbury University

ABSTRACT
Authors: Susan Krumdieck, Alibe Wassa, Jack A. Heinemann, Rukmini Gorthy, Johann Land, Catherine Bishop

TiO2 has been of high interest for antimicrobial activity (AMA) and self-cleaning properties. Recent research aimed at enhancing visible light AMA has focused on facet engineering and rutile-anatase heterojunctions of hydrothermally produced nanoparticles, and on carbon-sensitized mixtures. The science of visible AMA enhancement for nanoparticles is becoming clear, but the application of nanopowders in robust coatings on practical touch-surfaces is still a challenge. Pulsed-pressure MOCVD has been demonstrated as a way to economically coat 3-D stainless steel objects with TiO2 layers 5 to 15 m thick which show remarkable adhesion and durability. Here we report pp-MOCVD of a composite of nanostructured anatase-rutile-carbon (NsARC) on 304 stainless steel and the high AMA under UV exposure, but also under visible light and in the dark. The NsARC coating had Log-3 AMA (99.9% reduction of live cells) in both UV and visible light. The AMA in the dark and in ambient light was also higher than UV irradiated stainless steel. Our future work will investigate the role of the carbon by testing annealed samples, further investigate different bacteria species, and the effects of the processing parameters. We are also working with companies to up-scale the process and coating technology for coating fixtures for health care facilities.

BIO
Catherine Bishop
Associate Professor
University of Canterbury

Catherine earned her PhD in Materials Science from MIT in 2003. She continued her research on interfaces in ceramics during a post-doc and research fellowship at the University of Oxford. She joined the University in 2008. Her research interests include interface transitions, processing-structure-properties relations in alloys and bulk phase transformations. She has collaborated with the AEMS Laboratory on developing the fundamental science and materials for Pusled-Pressure MOCVD technology for industrial ceramic coatings on complex shaped metal objects. They are currently working to spin out a new company to deliver photoactive TiO2 antimicrobial coatings for touch surfaces in health care facilities.