At the instant when the drop was about to move, the contact angles at the advancing and receding contact lines were taken as the advancing and receding contact angles, respectively [25,26]. Washing fastness or durability was evaluated in reference to standard test method for fabric coating (AATCC Test Method 61-2006 test No. 2A). This standard wash procedure is equivalent to five cycles of home machine launderings. For convenience, we use the equivalent number of home machine launderings in this paper.