Fig. 2. Dependence of the apparent contact angle on the applied voltage for (a) 50 ± 3 μm, (b) 20 ± 2 μm and (c) 7 ± 1 μm thick films. Electrowetting experiments were conducted with (first row) water (γLA = 0.072 N m−1) and (second row) propylene glycol (γLA = 0.041 N m−1). The Lippmann equation is plotted for each corresponding initial contact angle, θ0, with a thickness of 50 μm, 20 μm and 7 μm, respectively (εo = 8.854 × 10−12 F m−1, εr = 2.65). (The discontinuity observed in (a) for the hardest dielectric at high voltages is a result of lateral movement of the contact line).
