Evaporation of elongated droplets on chemically stripe-patterned surfaces

We investigate the evaporation of elongated droplets on chemically striped patterned surfaces. Variation of elongation is achieved by depositing droplets on surfaces with varying ratios of hydrophobic and hydrophilic stripe widths. Elongated droplets evaporate faster than more spherical droplets. Both the lower contact angles and the elongation play a role in the diffusion process, leading to a decrease of the total evaporation time. Models for spherical cap-shaped droplets are applied to the elongated droplets and we show that they qualitatively agree. An empirical correction, taking into account the elongation, is proposed that describes the lifetimes of elongated droplets.