Research output: Contribution to Journal/Magazine › Journal article › peer-review
Research output: Contribution to Journal/Magazine › Journal article › peer-review
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TY - JOUR
T1 - Switching stiction and adhesion of a liquid on a solid
AU - Mertens, S.F.L.
AU - Hemmi, A.
AU - Muff, S.
AU - Groning, O.
AU - De Feyter, S.
AU - Osterwalder, J.
AU - Greber, T.
PY - 2016/6/30
Y1 - 2016/6/30
N2 - When a gecko moves on a ceiling it makes use of adhesion and stiction. Stiction-static friction-is experienced on microscopic and macroscopic scales and is related to adhesion and sliding friction. Although important for most locomotive processes, the concepts of adhesion, stiction and sliding friction are often only empirically correlated. A more detailed understanding of these concepts will, for example, help to improve the design of increasingly smaller devices such as micro-and nanoelectromechanical switches. Here we show how stiction and adhesion are related for a liquid drop on a hexagonal boron nitride monolayer on rhodium, by measuring dynamic contact angles in two distinct states of the solid-liquid interface: a corrugated state in the absence of hydrogen intercalation and an intercalation-induced flat state. Stiction and adhesion can be reversibly switched by applying different electrochemical potentials to the sample, causing atomic hydrogen to be intercalated or not. We ascribe the change in adhesion to a change in lateral electric field of in-plane two-nanometre dipole rings, because it cannot be explained by the change in surface roughness known from the Wenzel model. Although the change in adhesion can be calculated for the system we study, it is not yet possible to determine the stiction at such a solid-liquid interface using ab initio methods. The inorganic hybrid of hexagonal boron nitride and rhodium is very stable and represents a new class of switchable surfaces with the potential for application in the study of adhesion, friction and lubrication. © 2016 Macmillan Publishers Limited.
AB - When a gecko moves on a ceiling it makes use of adhesion and stiction. Stiction-static friction-is experienced on microscopic and macroscopic scales and is related to adhesion and sliding friction. Although important for most locomotive processes, the concepts of adhesion, stiction and sliding friction are often only empirically correlated. A more detailed understanding of these concepts will, for example, help to improve the design of increasingly smaller devices such as micro-and nanoelectromechanical switches. Here we show how stiction and adhesion are related for a liquid drop on a hexagonal boron nitride monolayer on rhodium, by measuring dynamic contact angles in two distinct states of the solid-liquid interface: a corrugated state in the absence of hydrogen intercalation and an intercalation-induced flat state. Stiction and adhesion can be reversibly switched by applying different electrochemical potentials to the sample, causing atomic hydrogen to be intercalated or not. We ascribe the change in adhesion to a change in lateral electric field of in-plane two-nanometre dipole rings, because it cannot be explained by the change in surface roughness known from the Wenzel model. Although the change in adhesion can be calculated for the system we study, it is not yet possible to determine the stiction at such a solid-liquid interface using ab initio methods. The inorganic hybrid of hexagonal boron nitride and rhodium is very stable and represents a new class of switchable surfaces with the potential for application in the study of adhesion, friction and lubrication. © 2016 Macmillan Publishers Limited.
KW - boron
KW - hydrogen
KW - rhodium
KW - boron derivative
KW - boron nitride
KW - adhesion
KW - electric field
KW - friction
KW - gas
KW - liquid
KW - lubricant
KW - solid
KW - surface roughness
KW - adsorption
KW - Article
KW - cell migration
KW - conformation
KW - contact angle
KW - desorption
KW - dipole
KW - electrowetting
KW - evaporation
KW - hydrogen bond
KW - hydrogen evolution
KW - hydrophobicity
KW - hysteresis
KW - lubrication
KW - microfluidics
KW - periodicity
KW - priority journal
KW - sliding friction
KW - solvation
KW - static electricity
KW - static friction
KW - surface area
KW - surface property
KW - animal
KW - chemistry
KW - electricity
KW - locomotion
KW - wettability
KW - Gekkonidae
KW - Adhesiveness
KW - Animals
KW - Boron Compounds
KW - Electricity
KW - Friction
KW - Hydrogen
KW - Locomotion
KW - Lubrication
KW - Rhodium
KW - Wettability
U2 - 10.1038/nature18275
DO - 10.1038/nature18275
M3 - Journal article
VL - 534
SP - 676
EP - 679
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7609
ER -