Highly ordered breath figures on pure chloroform fluid surface.

This article focuses on the in situ observation and analysis of breath figures (BFs)—water vapor condensation patterns—on the surface of pure chloroform, a volatile fluid, under static humid conditions. Using optical microscopy combined with image processing, the study reveals that BFs on chloroform form highly ordered arrays exhibiting two distinct power-law growth exponents of approximately 1.4 during a rapid growth stage and 0.22 during a slower growth stage, with water droplets reaching sizes up to about 4.5 μm before coalescence. The water droplets also display rapid, irregular motion with speeds up to 80 μm/s, attributed to strong convection currents and Marangoni effects induced by chloroform evaporation. Comparisons with BFs on nonvolatile fluids, volatile polymer solutions, and other volatile fluids indicate that the physical properties and evaporation rate of chloroform critically influence BF growth dynamics and ordering, contributing to a better understanding of the mechanisms behind ordered breath figures on volatile fluid surfaces.