ABSTRACT Fog formation and moisture condensation limit the performance of glass surfaces in optical, microfluidic, and sensing applications, where stable transparency under humid conditions is essential. Enhancing surface wettability represents an effective strategy to mitigate these effects; therefore, the development of methods to tailor glass wettability is of scientific and technological relevance. In this context, the present study investigates a controlled flame treatment of glass surfaces to enhance their hydrophilicity, with the extent and short‐ and long‐term stability depending on processing conditions. In particular, an in‐flame treatment is investigated, in which microscope glass slides are exposed to a premixed lean ethylene/air flame (equivalence ratio, Φ = 0.78) generated by a McKenna burner. The chemically active flame environment, rich in oxidizing radicals such as O and OH and in combustion products including H 2 O, enables rapid surface activation. Different exposure regimes are systematically compared, including short intermittent flame insertions and continuous exposure, to clarify the role of temporal continuity in the activation process. Static water contact angle measurements reveal a decrease from 42.36 ± 3.93° for pristine glass to approximately 12° after treatment, demonstrating a shift toward hydrophilicity. Additional stability assessments based on repeated mild cleaning cycles indicate that the persistence of the induced hydrophilicity depends on the flame exposure modality. Overall, these results demonstrate that flame treatment can serve as a rapid, scalable, and efficient route for glass surface activation, offering an alternative to plasma‐based techniques or prolonged thermal treatments for antifogging and related optical applications.
Griffo et al. (Wed,) studied this question.