Microbial Interactions with Carbon Nanotube-Polymer Nanocomposites

Polymers modified by the inclusion of carbon nanotubes (CNTs) are amongst the most widely used type of nanomaterial due to the ability of CNTs to enhance a wide range of polymer properties such as tensile strength, thermal stability and electrical conductivity. When these nanomaterials enter the environment, following consumer use their fate and persistence will be influenced by biodegradation processes initiated by microbial activity present in soils, surface waters, and landfill sites.

We are working to develop a systematic understanding of how CNT-polymer properties influence their interactions with different microbial populations and the implications of these findings for life cycle analysis. The first step in this study involves creating CNT-polymer composites that vary with respect to the type of polymer, CNT and CNT loading. These nanocomposites are characterized with analytical techniques including SEM, X-ray Photoelectron Spectroscopy, ATR-IR and contact angle measurements. Initial studies have explored how CNT loading influences bioattachment and biofilm formation processes, the precursors to biodegradation. The Figure below, obtained using confocal laser scanning microscopy in combination with live/dead staining, shows that the presence of higher CNT loadings in polyvinyl alcohol (PVOH) nanocomposites causes the surface to become increasingly toxic towards the microorganisms Pseudomonas aeruginosa. Future studies will address how CNT inclusion influences the biodegradation of polymer nanocomposites.

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Effect of CNT loading on microbial interactions with polymer (PVOH) nanocomposites (live cells – green; dead cells – red). The presence of CNTs at the surface is reveled by SEM images

 This work is being conducted in collaboration with Professor Ed Bouwer in the Department of Geography and Environmental Engineering at Johns Hopkins University.