Leyla Soleymani and Tohid Didar
McMaster University
Hamilton, Ontario, Canada

RepelWrap is a transparent, flexible plastic film that significantly repels liquid and microbial contaminants (viruses and bacteria) from surfaces, keeping them clean even under the most contaminating conditions. RepelWrap is an omniphobic surface technology (a surface repelling a broad range of contaminants) that uses engineered hierarchical materials to transform commercially available plastic wraps into repellent films. (Read our Web-only interview with the RepelWrap inventors.)

RepelWrap uses a novel nature-inspired concept to build pathogen repellency onto plastic surfaces. This concept uses structural hierarchy, wrinkles in the micron length scale decorated with particles in the nanometer length scale that are functionalized with molecular layers to repel contaminants by reducing surface energy and intermolecular forces. This programmable structural hierarchy is implemented on plastic surfaces using facile manufacturing processes (solution-processing) used by plastic manufacturers, demonstrating tremendous potential for large-volume manufacturing. RepelWrap can be manufactured onto biodegradable and “green” plastic materials to alleviate the increased concerns centered around material sustainability and recyclability.

RepelWrap has demonstrated remarkable properties in repelling a wide range of liquids including water, hexadecane, and blood with contact angles and sliding angles of 154°, 124°, 144°, and <5°, respectively, indicating that liquid contaminants roll off of these surfaces instead of sticking on them. RepelWrap was tested with Pseudomonas spp. and methicillin-resistant Staphylococcus aureus (both high-priority pathogens by the World Health Organization) as well as the human simplex virus (HSV). RepelWrap significantly reduced pathogen transfer and completely suppressed biofilm formation.

In the search to find a solution for reducing the spread of COVID-19, RepelWrap was evaluated by exposing it to viral contamination (using HSV having a similar size and morphology to SARS-CoV-2), demonstrating a remarkable reduction in viral transfer that is superior to that obtained with most disinfectants.

There is currently no technology of this type on the market — a versatile, flexible plastic wrap that works instantly to repel a wide range of contaminants. The existing antimicrobial surface technologies often use active antimicrobial agents that are not universal, increase microbial resistance, have long-term health concerns, or require long pathogen deactivation times (minutes to hours). RepelWrap, with its instant and wide-range repellency and its ability to repel rather than kill or deactivate pathogens, presents a unique and effective alternative to these technologies.

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This article first appeared in the December, 2020 issue of Tech Briefs Magazine.

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