TY - JOUR
T1 - Launching a Drop via Interplay of Buoyancy and Stick-jump Dissolution
AU - Zeng, Binglin
AU - Yang, Haichang
AU - Xu, Ben Bin
AU - Lohse, Detlef
AU - Zhang, Xuehua
N1 - Funding information: The authors thank Romain Billet, Kangkana Kalita, and Kai Leong Chong for the valuable discussions. D.L. acknowledges funding by the ERC Advanced Grant No. 740479-DDD and from the NWO MCEC project. B.X. is grateful for the support from the Engineering and Physical Sciences Research Council (EPSRC, UK) grant-EP/N007921. X.H.Z. acknowledges the funding support from the Natural Science and Engineering Research Council of Canada (NSERC)- Discovery Project, NSERC Alliance—Alberta Innovates Advance grants, the Canada Research Chair Program and Canada Foundation for Innovation, John R. Evans Leaders Fund.
PY - 2023/9/19
Y1 - 2023/9/19
N2 - According to Archimedes' principle, a submerged object with a density lower than that of aqueous acid solution is more buoyant than a smaller one. In this work, a remarkable phenomenon is reported wherein a dissolving drop on a substrate rises in the water only after it has diminished to a much smaller size, though the buoyancy is smaller. The drop consisting of a polymer solution reacts with the acid in the surrounding, yielding a water-soluble product. During drop dissolution, water-rich microdroplets form within the drop, merging with the external aqueous phase along the drop-substrate boundary. Two key elements determine the drop rise dynamics. The first is the stick-jump behavior during drop dissolution. The second is that buoyancy exerts a strong enough force on the drop at an Archimedean number greater than 1, while the stick-jump behavior is ongoing. The time of the drop rise is controlled by the initial size and the reaction rate of the drop. This novel mechanism for programmable drop rise may be beneficial for many future applications, such as microfluidics, microrobotics, and device engineering where the spontaneous drop detachment may be utilized to trigger a cascade of events in a dense medium.
AB - According to Archimedes' principle, a submerged object with a density lower than that of aqueous acid solution is more buoyant than a smaller one. In this work, a remarkable phenomenon is reported wherein a dissolving drop on a substrate rises in the water only after it has diminished to a much smaller size, though the buoyancy is smaller. The drop consisting of a polymer solution reacts with the acid in the surrounding, yielding a water-soluble product. During drop dissolution, water-rich microdroplets form within the drop, merging with the external aqueous phase along the drop-substrate boundary. Two key elements determine the drop rise dynamics. The first is the stick-jump behavior during drop dissolution. The second is that buoyancy exerts a strong enough force on the drop at an Archimedean number greater than 1, while the stick-jump behavior is ongoing. The time of the drop rise is controlled by the initial size and the reaction rate of the drop. This novel mechanism for programmable drop rise may be beneficial for many future applications, such as microfluidics, microrobotics, and device engineering where the spontaneous drop detachment may be utilized to trigger a cascade of events in a dense medium.
KW - drop detachment
KW - stick-jump dissolution
KW - phase separation
KW - on-drop reaction
U2 - 10.1002/smll.202303177
DO - 10.1002/smll.202303177
M3 - Article
JO - Small
JF - Small
SN - 1613-6810
M1 - 2303177
ER -