Organogels (eBook)

Professor Jean-Michel Guenet is Directeur de Recherche at CNRS and former head of the Institut Charles Sadron, Strasbourg, France, a CNRS-owned laboratory associated with the Université of Strasbourg. He has a degree in materials science engineering from Paris XIII University (1974), and obtained a PhD degree in 1980 at Université de Strasbourg (formerly Université Louis Pasteur). He spent a year at Bristol University, UK, under the guidance of Professor A. Keller as a post-doctoral fellow. He was a visiting scientist at NIST with Professor G.B. McKenna, Gaithersburg, USA, in 1985; a visiting professor at Université de Mons-Hainaut, Belgium, with Professor M. Dosière from 1995 to 2004; and an invited professor at Shizuoka University, Japan, with Professor H. Itagaki in 2002 and 2009. He has authored about 170 papers, and has also written two books on Thermoreversible Gelation of Polymers and Biopolymers (Academic Press, 1992), and on Polymer-solvent Molecular Compounds (Elsevier, 2008). In 1990, he was awarded the Dillon Medal of the American Physical Society for his work on polymer gels. He has also founded in 1996 of a series of conferences formerly entitled Polymer-solvent Complexes and Intercalates which has been renamed POLYSOLVAT in 2008. Since 2008 this series of conferences is sponsored by IUPAC as being one of its kind.

About the Author 7
Preface 9
Contents 11
1 Introduction 13
References 17
2 Gels: A Definition 18
2.1 Rheological Definition 19
2.2 Topological-Thermodynamic Definition 22
2.3 Summary 24
References 26
3 Thermodynamic and Kinetic Aspects 27
3.1 Some Basic Principles 27
3.1.1 Order of the Transition 27
3.1.2 Nucleation and Growth 29
3.2 The Temperature–Concentration Phase Diagrams 32
3.2.1 Some Relevant Theoretical Phase Diagrams 34
3.2.1.1 Solid–Liquid Phase Transition 34
3.2.1.2 Monotectic Transition 35
3.2.1.3 Molecular Compounds 37
3.2.1.4 Case for Two Crystal Forms: Metatectic Transition 39
3.2.2 Theoretical Expression for the Liquidus 39
3.2.3 Experimental Phase Diagrams 41
3.3 Summary 45
References 46
4 Molecular Structure and Morphology 47
4.1 The Microscopic Structure 47
4.2 The Mesoscopic Structure(s) 52
4.2.1 The Fibril’s Shape 52
4.2.2 About the “Critical” Gelation Concentration 61
4.2.3 The Junctions 63
4.3 The Macroscopic Structure(s). Gel Morphology 69
4.4 Summary 74
References 75
5 Solvent Role, Current Approaches 78
5.1 Binary Systems 78
5.2 Ternary Systems 83
5.3 Molecular Compound 85
5.4 Liquid Crystalline Solvents 88
5.5 Summary 89
References 89
6 Rheological Aspects 91
6.1 Some Theoretical and Practical Bases 91
6.2 Percolation Model Versus Fibrillar Model 93
6.3 Modulus Versus Concentration 96
6.4 Storage Modulus Versus Temperature 99
6.5 Summary 101
References 101
7 Hybrid Gels 103
7.1 Intermingled Gels 103
7.2 Sheathed Fibrils Gels 106
7.3 Hybrid Hydrogels with Graphene Oxide 110
7.4 Summary 111
References 111
8 Current and Potential Applications 113
8.1 Nucleating Agent 113
8.2 Hydrophobic Materials 115
8.3 Detection of Explosives 117
8.4 Mesoporous Catalysts 118
8.5 Highly Conducting Fibrils 119
8.6 Oil Extraction from Aqueous Media 121
8.7 Peptides Hydrogels for Medicinal Purposes 122
8.8 Summary 124
References 124
General Summary 126
Index 128