Figure 4

Variation of the averaged corona width (\(\overline{w}\) measured in mm) is normalized to the averaged radius of the droplet (\(\overline{R}\) measured in mm). It is plotted in (I), the averaged crack spacing (\(\overline{x}_c\)) is depicted in (II), and the averaged crack width (\({\overline{\lambda }}_c\)) is exhibited in (III) at different diluting concentrations (\(\phi \)). The dashed line shows the linear fit for the whole range of \(\phi \) from 100 to \(12.5\%\) (v/v). The solid lines display two linear fits—first one for the range from 100 to \(62\%\) (v/v); and the second one for 62 to \(12.5\%\) (v/v). The error bars correspond to the standard deviation. The macroscopic images illustrate the width of the corona (w), the radius of the droplet (R), the distance between the consecutive radial cracks (\(x_c\)), and the width between the consecutive radial cracks (\(\lambda _c\)). The dashed green circular line separates the corona from the central region in the droplet.