Fig. 5
From: The measurement of the surface energy of solids using a laboratory drop tower
Additional results, drop volume optimization and simulation of wetting without gravity. a The method was also used to measure the surface energy of a piece of Makrolon ® Polycarbonate (PC) (sides 1 and 2). According to the average of various references reported by Accu Dyne Tests™ (https://www.accudynetest.com/polytable_03.html?sortby=contact_angle): PP 30.21 ± 2.88 mJ/m2 (37 references); PTFE 21.41 ± 3.27 mJ/m2 (44 refs.); PC 42.68 ± 4.78 mJ/m2 (9 refs.). b Correlation between measurement accuracy and drop size for the PP-system and PTFE-system using the Bond (Eötvös) number. c The energy ratio Φ of the gravitational potential and the work done by the liquid–air interface could be used to find the optimal droplet volume. d The energies of the water–air and PP–air interfaces spontaneously do work to build the PP–water interface. e Using the values of the energies in the configuration κ′ it is possible to reconstruct the idealized spontaneous wetting of a drop in the absence of the gravity (see Section Theoretical Fundamentals of the Method)
