Free-surface profile of evaporative liquids at the vicinity of the contact line

Interfacial phenomenon, specifically those associated with evaporation from thin liquid films near the contact line of a liquid drop, plays a major role in many current engineering applications which require high local heat fluxes, as evident in heat pipes, grooved evaporators, fuel cells, and suction nucleate boiling devices (Potash and Wayner in Int J Heat Mass Transf 15:1851-1863, 1971; Hanchak et al. in Int J Heat Mass Transf 75:196-206, 2014). This study will prove useful in the improvement of such applications. Fluorescence microscopy was used as our main technique for investigating the free-surface profiles of evaporative liquids at the vicinity of the contact line, as it delivers sufficient range and resolution to address the challenge of capturing the microscopic and macroscopic aspects of this phenomenon. The free-surface profiles of relatively low evaporative liquids were compared with those of nonevaporative liquids, specifically one centistoke silicon oil was compared with one hundred centistokes silicon oil and qualitatively no difference has been observed between both profiles near the contact line.