One-second regeneration of superhydrophilicity and antifog performance of laser induced tungsten based micro-nano structure by flame treatment

In this study, hierarchical micro-nano structured glass surfaces were produced by a cost effective laser marker ablation of tungsten-coated glass. The treated surface demonstrated a water contact angle of 0 degrees, achieved and maintained remarkable antifog performance over 13 months without apparent degradation, which had rarely been reported. Remarkably, a one-second flame treatment fully restored the superhydrophilicity and antifog properties, an intervention not previously reported. Such structure also showcased exceptional self-cleaning property. Wenzel model could not explain the suboptimal hydrophilicity of highly rough surfaces, underscoring the necessity for a new model. The area density of capillary force used to estimates water spreading capability on a surface was proposed as a criterion for assessing the strength of hydrophilicity, aligning with preliminary experimental results.