Advanced Materials series: Will self-cleaning materials transform rail maintenance?
Superhydrophobic properties self-cleans through the repulsion of water particles from the surface. Materials with superhydrophilic properties use water to “sheet” between the dirt/debris and the material itself, which then removes the debris along with the water. Photocatalytic self-cleaning methods work by chemically breaking down fouling matter through emitting free radicals (an atom with an unpaired electron) which are created when the material is exposed to UV waves in light.
Self-cleaning materials can be used within the rail industry to reduce maintenance costs by keeping optical sensors/signals and the undercarriage of rolling stock clean. Self-cleaning materials such as titanium dioxide can be used within paints and train cab windscreens to reduce the need for regular maintenance as it uses photocatalytic and hydrophilic self-cleaning mechanisms to remove fouling matter whilst using the hydrophilic element to remove surface debris. Furthermore, hydrophobic coatings would decrease vandalism on the railway as graffiti paint would not adhere to the surface and thus will act as a deterrent. In addition, the “broken windows theory” suggests that the decrease in dirty surroundings will decrease the incentive for crime, improving security. Solar panels may be used in the future in stations or on trains, therefore a self-cleaning coating can be applied to maintain its efficiency as dirt build-up blocks light. Self-cleaning materials like Sharklet can be used within trains and stations, on hand rails and within toilets to prevent the spread of viruses, as well as creating spill-proof seats.
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