title: Study on Nanobubble-on-Pancake Objects Forming at Polystyrene/Water Interface.
abstract: Surface nanobubbles, which are the main gaseous state forming at the solid/liquid interface, have received extensive attention due to their peculiar features and potential applications. Nano/micro pancakes and interfacial gas enrichment (IGE) are observed at the water-solid interface, which suggest nanobubbles may coexist with IGE. An intuitive case for the coexistence of nanobubbles and IGE is the nanobubble-on-pancake-like objects. However, it still is not clear whether nanobubbles sit on top of an IGE or the IGE surrounds a nanobubble, which increasingly is seen to be important for understanding the stability and small contact angle of nanobubbles. In this study, the nanobubble-on-pancake-like objects were investigated on a polystyrene (PS) surface. Considering the nanobubble-like objects forming on PS film might be blisters formed because of osmosis, whether such objects are gaseous state or blisters therefore was investigated first. Then, the structure of the nanobubble-on-pancake-like object was analyzed, on the basis of which the stability of nanobubbles under tip perturbation was discussed. The pancake-like domains of the bubble-on-pancake composite disappeared, but the bubble part remained. This indicates that nanobubbles do not sit on top of the pancakes, but are pinned on the solid surface. This is in good agreement with the contact line pinning theory, and is helpful to understanding the abnormal long lifetime (stability) of nanobubbles.
authors.affiliation: School of Mechanical Engineering, Heilongjiang University of Science and Technology , Harbin 150022, China.
authors.forename: Dayong
authors.initials: D
authors.lastname: Li
authors.affiliation: School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China.
authors.forename: Yunlu
authors.initials: Y
authors.lastname: Pan
authors.affiliation: School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China.
authors.forename: Xuezeng
authors.initials: X
authors.lastname: Zhao
authors.affiliation: School of Mechanical and Electrical Engineering, Harbin Institute of Technology , Harbin 150001, China.|Nanoprobe Laboratory for Bio- & Nanotechnology and Biomimetics (NLB2), The Ohio State University , 201 West 19th Avenue, Columbus, Ohio 43210-1142, United States.
authors.forename: Bharat
authors.initials: B
authors.lastname: Bhushan