Tunable surface wettability of ZnO nanorods prepared by two-step method

► The proportion of nonpolar planes decreases with the increase of the growth time. ► The WCA of ZnO nanorods for 4 h and 10 h growth are ∼136° and ∼43°, respectively. ► The magnitude of WCA modulation with growth time is ∼93°. ► Effect of the proportion of nonpolar planes on the WCA has been studied. ► Increase of WCA reduction rate may be attributed to decrease of nonpolar planes.