Polymer-Mediated Phase Stability of Colloids (eBook)

Álvaro González García (Autor)

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2019 | 1st ed. 2019
XXII, 151 Seiten
Springer International Publishing (Verlag)
978-3-030-33683-7 (ISBN)

Infos

Colloid-polymer mixtures are subject of intensive research due to their wide range of applicability, for instance in coatings and food-stuffs. This thesis constitutes a fundamental investigation towards a better control over the stability of such suspensions. Through the chapters, different key parameters governing the stability of colloid-polymer mixtures are explored. How the colloid (pigment) shape and the effective polymer-colloid affinity modulate the stability of the suspension are examples of these key parameters. Despise the mostly theoretical results presented, the thesis is written in a format accessible to a broad scientific audience. Some of the equations of state presented might of direct use to experimentalists.  Furthermore, new theoretical insights about colloid-polymer mixtures are put forward. These include four-phase coexistences in effective two-component, quantification of depletant partitioning at high colloidal concentrations, multiple re-entrant phase behaviour of the colloidal fluid-solid coexistence, and a condition where polymers are neither depleted nor adsorbed from/to the colloidal surface.

Álvaro is an open-minded researcher with extensive experience in developing and applying theoretical models in soft matter. During his master research project he focused on the glass state of anisotropic particles. He contributed to develop a new experimental technique to characterize soft matter during his internship. In his PhD, he studied equilibrium phase transitions of different colloid-polymer mixtures. He aims research to be accessible to people from different fields and backgrounds. With a multidisciplinary approach, his ambition is to contribute to academic research in the fields of Physical Chemistry and (bio) Physics.

Inhalt

Supervisor’s Foreword 6
Preface 8
Publications related to this thesis 11
Acknowledgements 12
Contents 13
Symbols and Acronyms 16
1 Introduction 20
1.1 Colloids: Interactions and Phase Behaviour 20
1.2 Aim and Structure of This Thesis 22
1.3 Common Methodology 23
1.3.1 HCY, AOV, and PS Potentials 23
1.3.2 Second Virial Coefficient 24
1.3.3 FMSA: Closed Expressions for Interacting Colloids 26
1.3.4 FVT for PHS-Depletants 28
1.3.5 SCF for Micelle–Micelle Interactions 31
References 34
Part I Spherical Colloids 38
2 Tuning the Phase Diagram of Colloid–Polymer Mixtures 39
2.1 Introduction 39
2.2 FVT for Hard-Core Yukawa Colloids 40
2.3 Results and Discussion 41
2.3.1 Phase Diagrams 41
2.3.2 Critical End Point 44
2.3.3 Second Virial Coefficient at the Critical Point 45
2.3.4 Comparison with Monte Carlo Simulations 46
2.4 Conclusions and Outlook 48
References 48
3 Depletion-Driven Solid–Solid Coexistence in Colloid–Polymer Mixtures 50
3.1 Introduction 50
3.2 Geometrical Free Volume Fraction in the Solid State 51
3.3 Phase Diagrams and Solid–Solid Critical End Point 55
3.4 Conclusion 57
References 58
4 Unipletion in Colloid–Polymer Mixtures 61
4.1 Introduction 61
4.2 Interactions Between Hard Spheres: SCF and HCY 63
4.3 Polymers Near Surfaces 64
4.4 Pair Interactions and Second Virial Coefficient 68
4.5 Phase Diagrams 70
4.6 Conclusions 72
4.7 Pair Potentials: Further Results 72
References 75
Part II Anisotropic Hard Colloids 77
5 Phase Behaviour of Colloidal Superballs Mixed with Non-adsorbing Polymers 78
5.1 Introduction 78
5.2 Theory 79
5.2.1 Canonical Thermodynamic Expressions for Colloidal Superballs 79
5.2.2 Free Volume Theory for Cuboid–Polymer Mixtures 85
5.3 Results and Discussion 86
5.3.1 Phase Diagram of Hard Superballs 86
5.3.2 Free Volume Fraction 88
5.3.3 Phase Diagrams 88
5.3.4 Multi-phase Coexistence Overview 91
5.4 Concluding Remarks 94
References 97
6 Discotic Dispersions Mediated by Depletion 99
6.1 Introduction 99
6.2 Theory and Model Comparison 100
6.2.1 Basics of the Model 100
6.2.2 Free Volume Theory for Platelet–Polymer Mixtures 101
6.2.3 Model Comparison 103
6.3 Multi-phase Coexistences and Critical End Point 104
6.3.1 Isostructural Isotropic Coexistence 105
6.3.2 Isostructural Nematic Coexistence 105
6.3.3 Isostructural Columnar Coexistence: A First Account 107
6.3.4 Multiphase Coexistence: Overview and Experimental Comparison 109
6.4 Compartmentalisation in Crowded Discotics: Detailed Account of C1–C2 111
6.5 Conclusions 116
References 122
Part III Spherical Association Colloids 124
7 On the Colloidal Stability of Association Colloids 125
7.1 Introduction 125
7.2 Semi-analytical Expression for the Interaction Potential 126
7.3 Results and Discussion 128
7.3.1 Equilibrium Properties of Micelles with Varying Intermicelle Distance 128
7.3.2 Model Comparison and Lattice Geometry Effects 132
7.3.3 Influence of Coronal Block Solvency 134
7.3.4 Solvophilic Block Length Effects 135
7.3.5 Colloidal Phase Stability of Spherical Micelles 136
7.4 Conclusions 138
References 139
8 Polymer-Mediated Stability of Micellar Suspensions 142
8.1 Introduction 142
8.2 System Parameters 144
8.3 Results and Discussion 145
8.3.1 Dilute Homopolymer in a Micellar Suspension 146
8.3.2 Depletion in ACPMs 148
8.3.3 Coronal Physisorption in ACPMs 151
8.3.4 Corona Thickness and Colloidal Stability 154
8.3.5 On the Phase Stability of ACPMs 155
8.4 Conclusions 157
References 159
Appendix About the Author 162

Produkt-Details

• Erscheint lt. Verlag: 28.10.2019
• Reihe/Serie: Springer Theses
• Reihe/Serie: Springer Theses
• Zusatzinfo: XXII, 151 p. 67 illus., 2 illus. in color.
• Sprache: englisch
• Themenwelt: Naturwissenschaften ► Chemie
• Themenwelt: Naturwissenschaften ► Physik / Astronomie ► Atom- / Kern- / Molekularphysik
• Themenwelt: Wirtschaft
• Schlagworte: colloid-polymer phase stability • Colloid-polymer systems • Depletion interaction • Discotics • Four-phase coexistence • micelles • Re-entrant Phase Behaviour • Stability control of suspension • Superballs
• ISBN-10: 3-030-33683-2 / 3030336832
• ISBN-13: 978-3-030-33683-7 / 9783030336837