Preface My interest in liquid liquid interfaces, the reactions occurring at them and through them, as well as their physical properties and potential applications was initiated during my early days of doctoral studies at the National Centre for Scientific Research Demokritos in Athens, Greece. While I was working on the synthesis of polystyrene and polymethyl methacrylate composites with magnetic nanoparticles, I encountered the very interesting properties of conductive polymers, and expanded my work on polyaniline iron oxide nanocomposites. At this point, I became familiar with the work of Professor Richard Kaner on the interfacial polymerisation of aniline for the synthesis of nanofibres with excellent size distribution and homogeneous shape, which results in their superior performance as sensors. This method was shown to be a versatile tool for the synthesis and design of nanocomposites with noble metal nanoparticles (e.g., silver). The synthesis was mediated through in situ polymerisation whereby noble metal ions serve as initiators. Reviews and books on the synthesis and self-assembly of materials from interfaces are available. The purpose of this book is to give a holistic presentation of the active environments and materials arising from these dual systems comprised from a polar and nonpolar interface, two phases that are practically separate entities. A historical overview is presented, along with a section on the evolution of life and the self-assembly of hydrocarbons in aqueousbased, natural, or biological environments. Furthermore, I discuss the recent speculations on alternative, non-aqueous, environments that could enable liposome assembly at cryogenic temperatures and non-aqueous environments. iii
Polymers and Nanomaterials from Liquid-Liquid Interfaces: Synthesis, Self-Organisation and Applications With respect to the above, I present the appearance and importance of the interface in life forms, natural systems, and materials science. Various theories and speculations regarding the role of surfactants and micelles in the origin of life have arisen. However, even the simplest unicellular living organisms are complex beyond any imagination. Hence, it is practically impossible to give a comprehensive approach how humans have developed in such complexity through simple inorganic or hydrocarbon molecules. However, these theories present interesting insights on the self-organisation of matter. The book comprises five chapters and an extensive bibliography at the end of each chapter. Each of the five chapters is accompanied by introduction and conclusion parts. Chapter 1 initiates a discussion starting from the evolution of interfaces in natural environments. This discussion continues on the nature of the liquid liquid interface in Chapter 2, providing the physicochemical aspects (e.g., mass and electron transfer) behind this entity. This analysis on the nature of interfaces is necessary for understanding the processes that result in the self-organisation of matter (which is the subject of Chapter 3) and the synthesis of polymers and polymer thin films (Chapter 4). In the latter, extensive discussion on the magnetic, electronic transport and light-emitting properties of conjugated and conductive polymers is presented. Finally, Chapter 5 outlines the applications of interfaces and surfactants in catalysis, enhanced oil recovery with supercritical fluids, and other energy-related applications. I would like to thank my publisher, Smithers Rapra, and Mrs. Helene Chavaroche (commissioning editor) for providing me with the opportunity to publish this book. I hope that the direction of this work (i.e., fundamentals underlying liquid liquid interfacial systems and their applications) may be of interest in people working in industry, consultancies, as well as academia. I do not have handson experience with all the applications and experimental methods outlined in this book, so certain conclusions might be less than robust. Hence, I would be very happy to receive comments and suggestions by readers and hopefully an updated and more comprehensive edition of the book can be published in the near future. iv
Preface This work would not have been possible without the strict direction of my mentors during my doctoral studies, Drs Dimitrios Petridis and Dimitrios Niarchos, or the invaluable support and help given by Professors Athanasios Bourlinos, Vasileios Georgakilas and Kyriakos Porfyrakis. Dr. Panagiotis Dallas January 2017 v
Polymers and Nanomaterials from Liquid-Liquid Interfaces: Synthesis, Self-Organisation and Applications vi
Contents 1 Liquid Liquid Interfaces in Nature... 1 1.1 Introduction... 1 1.2 Prebiotic Chemistry... 2 1.2.1 The Path from Inorganic to Organic Matter is Mediated through Water... 2 1.2.2 Conversion of Inorganic Materials to Organic Matter through a Series of Complex Reactions... 4 1.2.3 External Sources of Energy... 5 1.2.4 Earth and Volcanoes: Heat from Inside the Earth... 8 1.3 Two-Phase Systems and Amphiphilic Molecules in Living Organisms... 9 1.3.1 Cell Membrane... 9 1.3.2 Artificial Photosynthesis... 17 1.3.3 Exotic Forms of Matter... 18 1.3.4 Non-Aqueous Environments for Cell Formation: Azotosomes in Cryogenic Environments... 20 1.4 Water and Organic Matter as Interfaces in the Formation of Natural Oil... 22 1.5 Conclusions... 25 2 Nature of the Liquid Liquid Interface... 33 2.1 Introduction... 33
Polymers and Nanomaterials from Liquid-Liquid Interfaces: Synthesis, Self-Organisation and Applications 2.2 Electron and Mass Transfer in Liquid Liquid Interfaces... 34 2.2.1 Mass Transfer: Diffusion Occurring at an Interface... 34 2.2.2 Electron Transfer: Redox Reaction at an Interface... 37 2.3 Interfacial Tension at the Boundary between Two Immiscible Liquids... 40 2.4 Polarity of the Interface... 46 2.4.1 Supercritical Fluids: Fluids Without Surface Tension and Gas Liquid Boundary... 46 2.5 Thickness of the Liquid Liquid Boundary... 52 2.6 Conclusions... 58 3 Self-Organisation of Nanomaterials at the Interface... 65 3.1 Introduction... 65 3.2 Micelle Formation... 66 3.2.1 Catanionics: Mixture of Anionic and Cationic Surfactants... 70 3.3 Organic Inorganic Vesicles... 71 3.4 Deoxyribonucleic Acid-Directed Self-Assembly... 76 3.5 Interface Energy and Interfacial Tension in Thin Films... 77 3.6 Self-Assembled Thin Films with Plasmonic Nanoparticles... 86 3.7 Redox Reactions from Functionalised Nanomaterials through Liquid Liquid Interfaces... 90 3.8 Photonic Crystals... 95 3.9 Biomimetics, Molecular Recognition and Nanomachines at a Liquid Liquid Interface... 96 3.10 Gyroid Polymeric Nanostructures from Interfaces... 99 3.11 Conclusions... 100 viii
Contents 4 Polymers from Interfaces... 113 4.1 Introduction... 113 4.2 Oxidative Polymerisation... 116 4.2.1 Polyaniline: Interfacial Polymerisation of Aniline... 116 4.2.1.1 Principles and Formation Mechanism of Nanofibres at the Interface... 116 4.2.1.2 Other Morphologies that can be Generated at an Interface... 120 4.2.2 Interfacial Polymerisation of Pyrrole: Formation of Thin Films and Noble Metal Nanocomposites... 121 4.2.3 Conductive Polymer Nanocomposites... 123 4.2.3.1 Noble Metal Nanocomposites through Reduction of Ions by Monomers... 123 4.2.3.2 Carbon Nanotubes and Graphene Nanocomposites... 124 4.3 Applications and Physical Properties... 125 4.3.1 Sensor Applications... 125 4.3.2 Single Crystalline Conductive Polymers: Ordering of Polyaniline Chains... 129 4.4 Electronic and Magnetic Properties... 130 4.4.1 Transport Mechanism: Conductivity of Polymers... 130 4.4.2 Polyaniline Nanoparticles with Metallic Electronic Transport... 132 4.4.3 Magnetic Properties of Conductive Polymers... 133 4.5 Light-Emitting Materials from Interfaces... 135 4.5.1 Polyaniline with Perfluorinated Pendant Groups... 135 ix
Polymers and Nanomaterials from Liquid-Liquid Interfaces: Synthesis, Self-Organisation and Applications 4.5.2 Photo-Functional Two-Dimensional Metal Organic Complexes... 137 4.6 Plastic Polymers Synthesised through Addition or Condensation Polymerisations... 139 4.7 Conclusions... 142 5 Interfaces in Energy Applications... 155 5.1 Introduction... 155 5.2 Energy Applications: Composite Anode Catalysts, Self-Assembled Monolayers and Capacitive Storage... 155 5.3 Use of Surfactants, Polymers, Nanoparticles and Supercritical Fluids in Oil and Gas Resources... 161 5.3.1 Enhanced Oil Recovery with Supercritical Fluids... 161 5.3.2 Role of Asphaltenes in Crude-Oil Emulsions... 162 5.3.3 Co-Solvents in Lignin Removal and Cellulose Treatment... 167 5.4 Catalysis in Liquid Liquid Interfaces and Water in Oil Emulsions... 168 5.5 Outlook and Perspectives... 178 Abbreviations... 191 Index... 195 x