Droplet rolling angle model of micro-nanostructure superhydrophobic coating surface Jinyu Chen, Junwu Chen, Lee Li, Shengwu Wang and Yi Xie Eur. Phys. J. E, 44 2 (2021) 25 Published online: 09 March 2021 DOI: 10.1140/epje/s10189-021-00036-7