Toward enhancement of water vapour condensation using wettability gradient surface

•Effect of contact angle hysteresis is quantified on independant experimental results.•Effect of this contact angle hysteresis is found to be important on the dynamic of the droplet.•Spatial heterogeneities of contact angle hysteresis have also to be taken into account.•Wettability gradient allows to maintain a dropwise condensation regime and thus to enhance the heat transfer.

This paper focuses on the behaviour of a liquid droplet on the surface of a treated solid substrate. We deal with the use of surface tension forces induced by heterogeneous wettability to allow the removal of the droplet. Our main aim is to present a new model able to predict the motion of a droplet of known volume along a wettability gradient taking into account the contact angle hysteresis: a key parameter in the dynamics of the droplet.