Superhydrophobic Surfaces

By Russell J. Crawford and Elena P. Ivanova

Superhydrophobic Surfaces analyzes the fundamental concepts of superhydrophobicity and gives insight into the design of superhydrophobic surfaces. The book serves as a reference for the manufacturing of materials with superior water-repellency, self-cleaning, anti-icing and corrosion resistance. It thoroughly discusses many types of hydrophobic surfaces such as natural superhydrophobic surfaces, superhydrophobic polymers, metallic superhydrophobic surfaces, biological interfaces, and advanced/hybrid superhydrophobic surfaces.

• Provides an adequate blend of complex engineering concepts with in-depth explanations of biological principles guiding the advancement of these technologies
• Describes complex ideas in simple scientific language, avoiding overcomplicated equations and discipline-specific jargon
• Includes practical information for manufacturing superhydrophobic surfaces
• Written by experts with complementary skills and diverse scientific backgrounds in engineering, microbiology and surface sciences

• Language: English
• Publisher: Elsevier Science
• Release date: Feb 19, 2015
• ISBN: 9780128013311

Russell J. Crawford

Professor Russell Crawford is currently the Dean of the Faculty of Life & Social Sciences at Swinburne University of Technology in Melbourne, Australia. He obtained his MSc from Swinburne in 1987, followed by a PhD from The University of Melbourne in 1995. He is the President of the Australian Council of Deans of Science and is a Fellow of the Royal Austraian Chemical Institute. His research is in the area of surface and colloid science, with his early work focusing on the surface chemistry of mineral flotation and the removal of heavy metals from aqueous environments. His more recent research has investigated the ways in which biological organisms interact with solid substrate surfaces, particularly those used in the construction of medical implants.

Book preview

Superhydrophobic Surfaces

Russell J. Crawford

School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Elena P. Ivanova

School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Table of Contents

Cover image

Title page

Copyright

Contributors

Editors Biographies

Preface

Acknowledgement

Chapter One. Superhydrophobicity – An Introductory Review

Chapter Two. Natural Superhydrophobic Surfaces

Introduction

Self-Cleaning Properties Arising from Hierarchical Structures

Hierarchical Structure of Surfaces on Aquatic Species

Summary

Chapter Three. The Design of Superhydrophobic Surfaces

Methods to Prepare Superhydrophobic Surfaces

Conclusions and Outlook

Chapter Four. Hydrophobicity of Nonwetting Soils

Nonwetting Soil and Its Impact on Water Transport

Superhydrophobicity of Soil Surfaces

Role of Soil Organic Matter on Water Repellency

Microstructure of Soil Organic Matter Coatings

Assessment of Water Repellency of Soil Surfaces

Influence of Surfactants on Nonwetting Soils

Chapter Five. Superhydrophobic Polymers

Introduction

Design of Superhydrophobic Polymers

Fabrication Techniques

Conclusions

Chapter Six. Metallic Superhydrophobic Surfaces

Introduction

Structuring of Metal Surfaces by Ultra-Short Pulsed Laser Irradiation

Influence of Laser Irradiation on the Chemical Composition of Metal Surfaces

Wetting Characterization

Combination of Laser Structuring with Coatings and Lubricants

Summary

Chapter Seven. Applications of Nanotextured Surfaces: Three-dimensional Aspects of Nanofabrication

Introduction

Nanoscale Structures and Their Functions

Emerging 3D Nanostructuring Technologies

Conclusions and Outlook

Chapter Eight. Biological Interactions with Superhydrophobic Surfaces

Introduction

Complexity and Dynamics

Protein Adsorption on Superhydrophobic Surfaces

Bacterial Interactions with Superhydrophobic Surfaces

Eukaryotic Cell–Tissue Interactions with Superhydrophobic Surfaces

Summary

Index

Copyright

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Notices

Knowledge and best practice in this field are constantly changing. As new research and experience broaden our understanding, changes in research methods, professional practices, or medical treatment may become necessary.

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ISBN: 978-0-12-801109-6

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Contributors

Kateryna Bazaka,     College of Science, Technology and Engineering, James Cook University, Townsville QLD, Australia

Chapter 5

Olga Bazaka,     College of Science, Technology and Engineering, James Cook University, Townsville QLD, Australia

Chapter 5

Chris M. Bhadra,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 3

Boris N. Chichkov,     Institut für Quantenoptik, Leibniz Universität Hannover and Laser Zentrum Hannover e.V.

Chapter 6

Russell J. Crawford,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapters 2, 3 and 8

Elena Fadeeva,     Institut für Quantenoptik, Leibniz Universität Hannover and Laser Zentrum Hannover e.V.

Chapter 6

Gediminas Gervinskas,     Australian Synchrotron, 800 Blackburn Rd, Clayton, Australia

Chapter 7

Elena P. Ivanova,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapters 2, 3 and 8

Tim S. Jakubov,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 1

Saulius Juodkazis,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 7

Vi Truong Khanh,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 4

Jürgen Koch,     Institut für Quantenoptik, Leibniz Universität Hannover and Laser Zentrum Hannover e.V.

Chapter 6

Sivashankar Krishnamoorthy,     Nanomaterials Unit, Science et Analyses des Materiaux, Centre Recherche Public, Gabriel Lippmann

Chapter 7

David E. Mainwaring,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapters 1 and 4

Pandiyan Murugaraj,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 4

Song Ha Nguyen,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapters 2 and 8

Vy T.H. Pham,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapter 3

Hayden K. Webb,     School of Science, Swinburne University of Technology, Hawthorn, Victoria, Australia

Chapters 2, 3 and 8

Editors Biographies

Russell J. Crawford is a Professor of Chemistry at Swinburne University of Technology. He obtained a Master of Science from Swinburne and a PhD from The University of Melbourne. He has held leadership positions in the university, including Dean of Science and Dean, Faculty of Life & Social Sciences. His research is in surface and colloid science, with early work focusing on mineral flotation and the removal of heavy metals from aqueous environments. His recent research focuses on understanding the ways in which biological organisms interact with solid substrate surfaces, such as those used in the construction of medical implants.

Elena P. Ivanova is a Professor at Swinburne University of Technology. She received a PhD from the Institute of Microbiology and Virology, Ukraine; a ScD from the Pacific Institute of Bio-organic Chemistry, Russian Federation; and a JD from The University of Melbourne. Before joining Swinburne University of Technology, hold postdoctoral positions at the New Energy and Industrial Technology Development Organization, Osaka, Japan and at the Center of Marine Biotechnology, University of Maryland, USA. Professional interests are concentrated on the fundamental and applied aspects of Nano/Biotechnology including planar microdevices, biomaterials, immobilization of biomolecules and microorganisms in micro/nano/environments, bacterial interactions with micro/nanostructured surfaces.

Preface

The degree to which water can spread on a surface, commonly referred to as wetting, is of great importance in many scientific, industrial, and medical processes. The degree of wettability of a surface determines the extent of interfacial contact area that can be established between a solid surface and water with which it comes into contact. This, in turn, determines the chemical or physical interactions that may occur between the two phases.

A thorough understanding of the way in which water interacts with solid surfaces provides us with the ability to control the many equilibrium processes that may take place between the phases. This occurs principally through the ability to tune the surface.

The term superhydrophobicity refers to a condition of extreme water repellency of a solid surface. A water droplet in contact with such a surface retains an almost spherical shape, with no spreading taking place, together with a minimal extent of contact between the two phases. Superhydrophobicity can lead to other interesting phenomena, most notably the ability for a surface to undergo self-cleaning. Here, a water droplet coming into contact with such a surface can easily roll across the surface on which it rests, collecting dust or other contaminating particles through adsorption or absorption as it moves, eventually rolling off the surface and taking with it the contaminating particles. Several naturally occurring self-cleaning surfaces such as that found on the upper surface of the lotus leaf are known to exist, and considerable efforts have been made in the last 20  years to reproduce their self-cleaning properties.

This book will discuss the underlying mechanisms responsible for the condition of superhydrophobicity and the major theories that ultimately determine the wettability of a surface. Following this, a summary of the naturally existing superhydrophobic surfaces, both biotic and abiotic, will be presented. A substantial part of this book has been dedicated to describing the methods currently being used to fabricate synthetic superhydrophobic surfaces. These will be discussed, together with an in-depth description of the various synthetic superhydrophobic materials that have been produced. Finally, the implications of superhydrophobicity and the role that this condition has played in biological systems will be explored.

Russell J Crawford,  and Elena P Ivanova,     Melbourne, 2015

Acknowledgement

We would like to extend our appreciation and sincere thanks to those colleagues, postgraduate students, friends, and family who assisted us during the process of writing this book. Most importantly, we thank our team of expert and outstanding coauthors; without their highly valued scholarly contribution, this book could not have been written.

BC and EF kindly acknowledge financial support of interdisciplinary research consortium of Hannover Biofabrication and The German Research Foundation (DFG SFB599 Sustaintable Bioresorbing and Permanent Implants of Metallic and Ceramic Materials and DFG Project Electrode optimization for neuroprostheses).

Russell J. Crawford,  and Elena P Ivanova

Chapter One

Superhydrophobicity – An Introductory Review

Abstract

Superhydrophobicity as a phenomenon has become an increasing focus of research and technological activity, where its fundamental aspects span surface chemistry, chemical physics, and cellular biology. Additionally, its significance to the behavior of natural systems, interfacial fluid dynamics, and biotechnology represents an area rapidly gaining potential importance. Detailed reviews have progressively explored superhydrophobicity from a number of viewpoints (e.g., Ma and Hill, 2006; Quéré, 2002; Shirtcliffe et al., 2010). Here, aspects underlying this wetting behavior are illustrated. It has long been recognized that surface roughness has a profound effect on wetting behavior, in particular through apparent contact angles and subsequent contact angle hysteresis (Bico et al., 2001; Quéré, 2008). Quéré (2008) points out that both chemical and structural surface heterogeneity can cause pinning of the three-phase contact line (TPL) of an advancing wetting front, whereby the difference in the advancing and receding contact angles produces a Laplace pressure and hence a force resisting further liquid advancement. Movement of the wetting front (advancing and receding) can be viewed as a kinetic process in response to changing forces at the TPL that characteristically produce jumps in the movement of this line. Rough and microstructured surfaces inherently increase hydrophobicity of hydrophobic surfaces through two very different mechanisms: a purely geometrical increase in the actual surface area with respect to its projected area generally termed the Wenzel state (Wenzel, 1936) and a composite interfacial effect arising from an air–water interface when air is trapped between microstructural features of the surface ahead of the advancing wetting front forming a Cassie–Baxter state (Cassie and Baxter, 1944), as illustrated in Figure 1. As such, these conditions represent homogeneous and heterogeneous surface wetting systems, respectively, and in both cases are derived from the result of variations in the interfacial energy of the substrate phase(s) solid or solid-vapor.

Keywords

Biotechnology; Natural systems; Superhydrophobicity; Three-phase contact line; Wettability

Glossary

TPL

   three-phase contact line

S-L-V

   solid-liquid-vapour phases

CMC

   critical micelle concentration

Superhydrophobicity as a phenomenon has become an increasing focus of research and technological activity, where its fundamental aspects span surface chemistry, chemical physics, and cellular biology. Additionally, its significance to the behavior of natural systems, interfacial fluid dynamics, and biotechnology represents an area rapidly gaining potential importance. Detailed reviews have progressively explored superhydrophobicity from a number of viewpoints (e.g., Ma and Hill, 2006; Quéré, 2002; Shirtcliffe et al., 2010). Here, aspects underlying this wetting behavior are illustrated. It has long been recognized that surface roughness has a profound effect on wetting behavior, in particular through apparent contact angles and subsequent contact angle hysteresis (Bico et al., 2001; Quéré, 2008). Quéré (2008) points out that both chemical and structural surface heterogeneity can cause pinning of the three-phase contact line (TPL) of an advancing wetting front, whereby the difference in the advancing and receding contact angles produces a Laplace pressure and hence a force resisting further liquid advancement. Movement of the wetting front (advancing and receding) can be viewed as a kinetic process in response to changing forces at the TPL that characteristically produce jumps in the movement of this line. Rough and microstructured surfaces inherently increase hydrophobicity of hydrophobic surfaces through two very different mechanisms: a purely geometrical increase in the actual surface area with respect to its projected area generally termed the Wenzel state (Wenzel, 1936) and a composite interfacial effect arising from an air–water interface when air is trapped between microstructural features of the surface ahead of the advancing wetting front forming a Cassie–Baxter state (Cassie and Baxter, 1944), as illustrated in Figure 1. As such, these conditions represent homogeneous and heterogeneous surface wetting systems, respectively, and in both cases are derived from the result of variations in the interfacial energy of the substrate phase(s) solid or solid-vapor.

Figure 1  Contact angles on structured surfaces in the classic Wenzel (W) and Cassie–Baxter (C–B) states, respectively, where r is the physical amplification of surface area due to roughness and f S is the fractional area in contact with air. Adapted from Shirtcliffe et al. (2010).

Marmur characterized superhydrophocity according to two criteria (Marmur, 2004), a very high contact angle and very low drop roll-off angle, as well as addressing the transition between these states in terms of their metastability and its impact on superhydrophobicity (Marmur, 2003). Since the free energy increases with increasing contact angle, the state that is most stable is represented by that with lowest contact angle. Gao and Yan (2009) and Quéré (2008) point out that due to local energy minima, a water drop cannot only assume multiple energy states but also coexist on a particular surface, and from the energy barrier for the transition Cassie–Baxter to the Wenzel state, surface geometry influences the interfacial energy requirement to reach equilibrium whether homogeneous or heterogeneous wetting is involved.

Pinning of the advancing TPL is also dependent on the topology (feature size, spacing, and shape). Shirtcliffe et al. (2010) and McHale (2007) note that this also determines the observed contact angle and consistency with the Wenzel and Cassie–Baxter models since the incremental advancing area is assumed to characterize the surface overall. And,