50 years on, and amid a viral pandemic, the topic of self-cleaning and hydrophobic materials has re-entered the mainstream with a vengeance.
Hydrophobic textiles or water-resistant textiles?
Hydrophobicity is not a new concept, but its applications certainly are, and especially in the medical field.
Materials in medicine are often disinfected with harsh chemicals or microbicides. The problem here is that microbes evolve resistances to these substances, quickly reducing their effectiveness.
Consistent over-application of these substances also leads to the evolution of so-called “superbugs”, such as MRSA, which are completely unaffected by common microbicides and therefore pose a serious threat of untreatable infection. All these factors have made self-cleaning, hydrophobic surfaces of particular interest.
Creating a hydrophobic material on a flat, solid surface is relatively simple because the surface makes for a foundation for the regular asperities needed for hydrophobicity. Making hydrophobic textiles is another proposition entirely, as all the shifting peaks and troughs of the warps and wefts are almost the logical opposite of the ideal flat surface mentioned before.
While ostensibly hydrophobic textiles exist, it’s more reasonable to call these textiles water-resistant than hydrophobic. The famous Gore-tex, for instance, resists water simply by having holes smaller than typical water drops.
However, these materials still wet like any others, and therefore require an additional chemical hydrophobic spray coating. This application wears off over time, further reducing the hydrophobicity.