| Preface | 7 |
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| Notation | 9 |
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| 1 What is surface tension? | 19 |
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| 1.1 Surface tension and its definition | 19 |
| 1.2 Physical origin of the surface tension of liquids | 20 |
| 1.3 Temperature dependence of the surface tension | 23 |
| 1.4 Surfactants | 24 |
| 1.5 The Laplace pressure | 24 |
| 1.6 Surface tension of solids | 26 |
| 1.7 Values of surface tensions of solids | 27 |
| Appendix 1A. The short-range nature of intermolecular forces | 28 |
| Appendix 1B. The Laplace pressure from simple reasoning | 28 |
| Bullets | 29 |
| References | 30 |
| 2 Wetting of ideal surfaces | 31 |
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| 2.1 What is wetting? The spreading parameter | 31 |
| 2.2 The Young equation | 32 |
| 2.3 Wetting of flat homogeneous curved surfaces | 35 |
| 2.4 Line tension | 37 |
| 2.5 Disjoining pressure | 38 |
| 2.6 Wetting of an ideal surface: influence of absorbed liquid layers and the liquid vapor | 40 |
| 2.7 Gravity and wetting of ideal surfaces: a droplet shape and liquid puddles | 42 |
| 2.8 The shape of the droplet and the disjoining pressure | 45 |
| 2.9 Distortion of droplets by an electric field | 47 |
| 2.10 Capillary rise | 48 |
| 2.11 The shape of a droplet wetting a fiber | 51 |
| 2.12 Wetting and adhesion. The Young-Dupre equation | 53 |
| 2.13 Wetting transitions on ideal surfaces | 54 |
| 2.14 How the surface tension is measured? | 55 |
| 2.14.1 The Du Nouy ring and the Wilhelmy plate methods | 55 |
| 2.14.2 The pendant drop method | 56 |
| 2.14.3 Maximum bubble pressure method | 57 |
| 2.14.4 Dynamic methods of measurement of surface tension | 58 |
| 2.15 Measurement of surface tension of solids | 61 |
| Appendix 2A. Transversality conditions | 62 |
| Appendix 2B. Zisman plot | 63 |
| Bullets | 64 |
| References | 64 |
| 3 Contact angle hysteresis | 68 |
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| 3.1 Contact angle hysteresis: its sources and manifestations | 68 |
| 3.2 Contact angle hysteresis on smooth homogeneous substrates | 70 |
| 3.3 Strongly and weakly pinning surfaces | 71 |
| 3.4 Qualitative characterization of the pinning of the triple line | 75 |
| 3.5 The zero eventual contact angle of evaporated droplets and its explanation | 76 |
| 3.6 Contact angle hysteresis and line tension | 77 |
| 3.7 More physical reasons for the contact angle hysteresis on smooth ideal surfaces | 78 |
| 3.8 Contact angle hysteresis on chemically heterogeneous smooth surfaces: the phenomenological approach. Acquaintance with the apparent contact angle | 79 |
| 3.9 The phenomenological approach to the hysteresis of the contact angle developed by Vedantam and Panchagnula | 80 |
| 3.10 The macroscopic approach to the contact angle hysteresis, the model of Joanny and de Gennes | 81 |
| 3.10.1 Elasticity of the triple line | 81 |
| 3.10.2 Contact angle hysteresis in the case of a dilute system of defects | 84 |
| 3.10.3 Surfaces with dense defects and the fine structure of the triple line | 84 |
| 3.11 Deformation of the substrate as an additional source of the contact angle hysteresis | 86 |
| 3.12 How the contact angle hysteresis can be measured | 87 |
| 3.13 Roughness of the substrate and the contact angle hysteresis | 89 |
| 3.14 Use of contact angles for characterization of solid surfaces | 89 |
| Appendix 3A. A droplet on an inclined plane | 91 |
| Bullets | 92 |
| References | 93 |
| 4 Dynamics of wetting | 96 |
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| 4.1 The dynamic contact angle | 96 |
| 4.2 The dynamics of wetting: the approach of Voinov | 96 |
| 4.3 The dynamic contact angle in a situation of complete wetting | 98 |
| 4.4 Dissipation of energy in the vicinity of the triple line | 100 |
| 4.5 Dissipation of energy and the microscopic contact angle | 101 |
| 4.6 A microscopic approach to the displacement of the triple line | 101 |
| 4.7 Spreading of droplets: Tanner’s law | 102 |
| 4.8 Superspreading | 103 |
| 4.9 Dynamics of filling of capillary tubes | 103 |
| 4.10 The drag-out problem | 105 |
| 4.11 Dynamic wetting of heterogeneous surfaces | 106 |
| Bullets | 107 |
| References | 108 |
| 5 Wetting of rough and chemically heterogeneous surfaces: the Wenzel and Cassie models | 110 |
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| 5.1 General remarks | 110 |
| 5.2 The Wenzel model | 110 |
| 5.3 Wenzel wetting of chemically homogeneous curved rough surfaces | 112 |
| 5.4 The Cassie-Baxter wetting model | 114 |
| 5.5 The Israelachvili and Gee criticism of the Cassie-Baxter model | 115 |
| 5.6 Cassie-Baxter wetting in a situation where a droplet partially sits on air | 116 |
| 5.7 The Cassie-Baxter wetting of curved surfaces | 119 |
| 5.8 Cassie-Baxter impregnating wetting | 119 |
| 5.9 The importance of the area adjacent to the triple line in the wetting of rough and chemically heterogeneous surfaces | 121 |
| 5.10 Wetting of gradient surfaces | 125 |
| 5.11 The mix
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