Undressing a Water Marble on Oil Film

Due to a great contact angle with substrate as well as low resistance to motion and stable structure of superhydrophobic powder shell, liquid marbles display attractive potential for easy actuation and manipulation. This work shows the dynamical behavior of a rolling liquid marble on oil film. Static liquid marbles display a much larger contact angle than water drops on an oil film. When liquid marbles move on oil film, three consecutive stages are observed. The first stage exhibits a linear relationship versus the remaining time, implying that liquid marbles are rolling on oil film and the attached particles are multilayer. When the particles become locally monolayer, the transient stage begins and the advancing angle is much larger than receding angle. At this time, liquid marble is sliding rather than rolling. Finally, liquid marble is captured by oil film and spreads to be a cap owing to the liquid–liquid contact. This work introduces an approach to partially undress particle layers and disintegrate liquid marbles, expecting to facilitate the optical probing from the transparent bottom of liquid marbles.