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Effect of Cassie-Baxter versus Wenzel states on ice adhesion: A fracture toughness approach
Graphical abstract Display Omitted
Highlights Novel fracture mechanic based approach to study ice adhesion to superhydrophobic surfaces. Effect of Cassie and Wenzel ice are quantified through experimental investigations. The effect of the microstructure is modeled with a semi-analytical approach, and good agreement with experiments is found. The semi-analytical model is employed to study the effect of the microstructure geometry on ice adhesion
Abstract Ice adhesion to superhydrophobic surfaces is most of the time studied regarding their wetting properties, in attempts to predict the best candidates to promote low ice adhesion. However, no clear correlation between water repellency and ice adhesion has yet been defined, thus limiting the development of low ice adhesion superhydrophobic surfaces to empirical testing. The present study puts forward a mechanical based approach (usually used for bonded joints) to rationalize the role of the surface structure on ice adhesion. Experimental observations on a single microtextured substrate form the basis for the development of a fracture toughness analysis. Compared to a smooth aluminum substrate, shear ice adhesion measurements show that adhesion increased by 30% when ice penetrated the surface structure microgrooves (Wenzel ice) or decreases by 36% when air remained trapped beneath the ice (Cassie ice). Post-mortem observations of the fracture surfaces were performed using a replica technique. Formulas were derived to compute the interfacial fracture toughness of Cassie and Wenzel ice, depending on the geometry of the microtexture. The fracture toughness was then used as an input parameter into a finite element model comprising a cohesive zone layer to model the interface. This semi-analytical approach gave values in good agreement with experimental results, thus showing the relevance of the present toughness analysis.
Effect of Cassie-Baxter versus Wenzel states on ice adhesion: A fracture toughness approach
Graphical abstract Display Omitted
Highlights Novel fracture mechanic based approach to study ice adhesion to superhydrophobic surfaces. Effect of Cassie and Wenzel ice are quantified through experimental investigations. The effect of the microstructure is modeled with a semi-analytical approach, and good agreement with experiments is found. The semi-analytical model is employed to study the effect of the microstructure geometry on ice adhesion
Abstract Ice adhesion to superhydrophobic surfaces is most of the time studied regarding their wetting properties, in attempts to predict the best candidates to promote low ice adhesion. However, no clear correlation between water repellency and ice adhesion has yet been defined, thus limiting the development of low ice adhesion superhydrophobic surfaces to empirical testing. The present study puts forward a mechanical based approach (usually used for bonded joints) to rationalize the role of the surface structure on ice adhesion. Experimental observations on a single microtextured substrate form the basis for the development of a fracture toughness analysis. Compared to a smooth aluminum substrate, shear ice adhesion measurements show that adhesion increased by 30% when ice penetrated the surface structure microgrooves (Wenzel ice) or decreases by 36% when air remained trapped beneath the ice (Cassie ice). Post-mortem observations of the fracture surfaces were performed using a replica technique. Formulas were derived to compute the interfacial fracture toughness of Cassie and Wenzel ice, depending on the geometry of the microtexture. The fracture toughness was then used as an input parameter into a finite element model comprising a cohesive zone layer to model the interface. This semi-analytical approach gave values in good agreement with experimental results, thus showing the relevance of the present toughness analysis.
Effect of Cassie-Baxter versus Wenzel states on ice adhesion: A fracture toughness approach
Huré, Martin (author) / Olivier, Philippe (author) / Garcia, Julien (author)
2021-11-17
Article (Journal)
Electronic Resource
English
Ice adhesion , Superhydrophobic , Microtexture , Wenzel ice , Icephobic , Cohesive zone model , a , Width of the ridges of the microtexture (m) , b , Spacing between two ridges of the microtexture (m) , c , Depth of the grooves of the microtexture (m) , <math xmlns="http://www.w3.org/1998/Math/MathML"><mover><mi>E</mi> <mo>¯</mo></mover></math> , Effective elastic modulus (MPa) , <italic>F</italic> <inf><italic>max</italic></inf> , Maximum force required to debond the ice during the pusher test (N) , <italic>G</italic> , Energy release rate (J.m<sup>−2</sup>) , <italic>G</italic> <inf><italic>c</italic></inf> , Critical energy release rate (J.m<sup>−2</sup>) , <italic>G</italic> <inf><italic>ic</italic></inf> , Critical energy release rate where i=I,II, III refers to the crack opening mode (J.m<sup>−2</sup>) , <italic>G</italic> <inf><italic>c</italic>,<italic>coh</italic></inf> , Critical energy release rate of ice (J.m<sup>−2</sup>) , <italic>G</italic> <inf><italic>c</italic>,<italic>int</italic></inf> , Critical energy release rate of ice/Aluminum interface (J.m<sup>−2</sup>) , <italic>G</italic> <inf><italic>app</italic></inf> , Apparent fracture toughnes (J.m<sup>−2</sup>) , <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mi>G</mi> <mi>app</mi> <mi>C</mi></msubsup></math> , Apparent fracture toughness for the Cassie ice/microtexture interface (J.m<sup>−2</sup>) , <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mi>G</mi> <mi>app</mi> <mi>W</mi></msubsup></math> , Apparent fracture toughness for the Wenzel ice/microtexture interface (J.m<sup>−2</sup>) , h , Ice thickness (m) , <italic>K</italic> , Stress intensity factor (MPa.m<sup>1/2</sup>) , <italic>K</italic> <inf>1</inf>, <italic>K</italic> <inf>2</inf> , Mode I and mode II stress intensity factors (MPa.m<sup>1/2</sup>) , <italic>K</italic> <inf><italic>i</italic></inf> , Penalty stiffness of cohesive elements where i=I,II, III is the crack opening mode (MPa.m<sup>−1</sup>) , <italic>l</italic> , Characteristic dimension of the system (m) , <italic>l</italic> <inf><italic>c</italic></inf> , Cohesive length of the interface (m) , <italic>L</italic> , Initial bonded length (m) , <italic>p</italic> , Distance from the crack tip (m) , <italic>r</italic> , Aspect ratio of the microtexture , <italic>r</italic> <inf><italic>c</italic></inf> , Critical aspect ratio of the microtexture , <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mi>t</mi> <mi>i</mi> <mn>0</mn></msubsup></math> , Interfacial strength, where i=I,II, III refers to the crack opening mode (MPa) , <italic>t</italic> <inf><italic>i</italic></inf> , Traction across the interface, where i=I,II, III refers to the crack opening mode (MPa) , <italic>δ</italic> <inf><italic>i</italic></inf> , Crack faces displacement, where i=I,II, III refers to the crack opening mode (m) , <italic>δ</italic> <inf><italic>ic</italic></inf> , Ultimate displacement, where i=I,II, III refers to the crack opening mode (m) , <math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mi>δ</mi> <mi>i</mi> <mn>0</mn></msubsup></math> , Crack faces displacement at t<math xmlns="http://www.w3.org/1998/Math/MathML"><msubsup><mrow></mrow> <mi>i</mi> <mn>0</mn></msubsup></math>, where i=I,II, III refers to the crack opening mode (m) , <italic>ε</italic> , Elastic mismatch parameter , <italic>μ</italic> , Shear modulus (MPa) , <italic>ν</italic> , Poisson's ratio , <italic>ξ</italic> , Reference length (m) , <italic>τ</italic> , Shear ice adhesion strength (kPa) , <italic>ψ</italic> , Phase angle of the mode mixity (°)
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