On the maximum spreading diameter of impacting droplets on well-prepared solid surfaces.

This paper presents a systematic study of liquid droplet impact on three polymer surfaces: poly(methyl methacrylate), poly(methyl methacrylate/n-butyl methacrylate), and poly(n-butyl methacrylate). Changing from one surface to the next represents an incremental variation in solid surface tensions of 5-6 mJ/m2. These surfaces were prepared through careful experimental procedures that were used for the determination of solid surface tensions from contact angles. Our data for the maximum spreading diameter of water and formamide impacting on these surfaces were compared with those predicted from literature models. Of the models selected, we modified the model of Pasandideh-Fard et al. [Phys. Fluids 1996, 8, 650] and the results yielded a least error of only 5.09 +/- 5.05% in the determination of the maximum spreading diameter. The improved model was also compared with literature data, and good agreement was found. Of course, any such comparisons would rely on accurate experimental impact dynamics data on carefully prepared surfaces.