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Towards a Technique for Controlling Wettability Characteristics and Conditioning Film Formation on Polyethylene Terephthalate (PET) Through Laser Surface Engineering
D.G. Waugh and J. Lawrence

Bacteria attachment to a surface is initiated by the adsorption of molecules to form a conditioning film (protein layer) on the surface of a substratum. The nature of the substratum strongly influences the composition of the adsorbed protein layer which, in turn, affects the interaction of bacterial cells. Fundamental interactions between proteins adsorbed from bacterial growth media (no-cell adhesion) and CO2 laser surface engineered polyethylene terephthalate (PET). The influence of interfacial wetting on the initial film conditioning of the CO2 laser surface engineered PET was analysed using contact angle measurements, elucidating the relationship between surface roughness parameters, wettability characteristics and conditioning film formation. Chemical analysis of the CO2 laser surface engineered PET surfaces revealed that the recorded changes to the surface energy and wettability were the result of surface morphology changes rather than modification of the chemical structure. The conditioning film adsorbed onto the CO2 laser engineered PET surfaces was found to increase the wetting of the samples. This work demonstrates that CO2 laser irradiation of the surface of PET provides a viable means for controlling interfacial wettability characteristics and conditioning film formation, leading to an effective and efficient means of producing antibacterial surfaces.

Keywords: CO2 laser, polyethylene terephthalate (PET), conditioning film, biofilm, wettability, contact angle, surface energy, laser surface engineering

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