González García Polymer-Mediated Phase Stability of Colloids

1. Auflage 2019
ISBN: 978-3-030-33683-7
Verlag: Springer International Publishing
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 162 Seiten

Reihe: Springer Theses

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.

Autoren/Hrsg.

González García, Álvaro

Inhaltsverzeichnis

1;Supervisor’s Foreword;6
2;Preface;8
3;Publications related to this thesis;11
4;Acknowledgements;12
5;Contents;13
6;Symbols and Acronyms;16
7;1 Introduction;20
7.1;1.1 Colloids: Interactions and Phase Behaviour;20
7.2;1.2 Aim and Structure of This Thesis;22
7.3;1.3 Common Methodology;23
7.3.1;1.3.1 HCY, AOV, and PS Potentials;23
7.3.2;1.3.2 Second Virial Coefficient;24
7.3.3;1.3.3 FMSA: Closed Expressions for Interacting Colloids;26
7.3.4;1.3.4 FVT for PHS-Depletants;28
7.3.5;1.3.5 SCF for Micelle–Micelle Interactions;31
7.4;References;34
8;Part I Spherical Colloids;38
9;2 Tuning the Phase Diagram of Colloid–Polymer Mixtures;39
9.1;2.1 Introduction;39
9.2;2.2 FVT for Hard-Core Yukawa Colloids;40
9.3;2.3 Results and Discussion;41
9.3.1;2.3.1 Phase Diagrams;41
9.3.2;2.3.2 Critical End Point;44
9.3.3;2.3.3 Second Virial Coefficient at the Critical Point;45
9.3.4;2.3.4 Comparison with Monte Carlo Simulations;46
9.4;2.4 Conclusions and Outlook;48
9.5;References;48
10;3 Depletion-Driven Solid–Solid Coexistence in Colloid–Polymer Mixtures;50
10.1;3.1 Introduction;50
10.2;3.2 Geometrical Free Volume Fraction in the Solid State;51
10.3;3.3 Phase Diagrams and Solid–Solid Critical End Point;55
10.4;3.4 Conclusion;57
10.5;References;58
11;4 Unipletion in Colloid–Polymer Mixtures;61
11.1;4.1 Introduction;61
11.2;4.2 Interactions Between Hard Spheres: SCF and HCY;63
11.3;4.3 Polymers Near Surfaces;64
11.4;4.4 Pair Interactions and Second Virial Coefficient;68
11.5;4.5 Phase Diagrams;70
11.6;4.6 Conclusions;72
11.7;4.7 Pair Potentials: Further Results;72
11.8;References;75
12;Part II Anisotropic Hard Colloids;77
13;5 Phase Behaviour of Colloidal Superballs Mixed with Non-adsorbing Polymers;78
13.1;5.1 Introduction;78
13.2;5.2 Theory;79
13.2.1;5.2.1 Canonical Thermodynamic Expressions for Colloidal Superballs;79
13.2.2;5.2.2 Free Volume Theory for Cuboid–Polymer Mixtures;85
13.3;5.3 Results and Discussion;86
13.3.1;5.3.1 Phase Diagram of Hard Superballs;86
13.3.2;5.3.2 Free Volume Fraction;88
13.3.3;5.3.3 Phase Diagrams;88
13.3.4;5.3.4 Multi-phase Coexistence Overview;91
13.4;5.4 Concluding Remarks;94
13.5;References;97
14;6 Discotic Dispersions Mediated by Depletion;99
14.1;6.1 Introduction;99
14.2;6.2 Theory and Model Comparison;100
14.2.1;6.2.1 Basics of the Model;100
14.2.2;6.2.2 Free Volume Theory for Platelet–Polymer Mixtures;101
14.2.3;6.2.3 Model Comparison;103
14.3;6.3 Multi-phase Coexistences and Critical End Point;104
14.3.1;6.3.1 Isostructural Isotropic Coexistence;105
14.3.2;6.3.2 Isostructural Nematic Coexistence;105
14.3.3;6.3.3 Isostructural Columnar Coexistence: A First Account;107
14.3.4;6.3.4 Multiphase Coexistence: Overview and Experimental Comparison;109
14.4;6.4 Compartmentalisation in Crowded Discotics: Detailed Account of C1–C2;111
14.5;6.5 Conclusions;116
14.6;References;122
15;Part III Spherical Association Colloids;124
16;7 On the Colloidal Stability of Association Colloids;125
16.1;7.1 Introduction;125
16.2;7.2 Semi-analytical Expression for the Interaction Potential;126
16.3;7.3 Results and Discussion;128
16.3.1;7.3.1 Equilibrium Properties of Micelles with Varying Intermicelle Distance;128
16.3.2;7.3.2 Model Comparison and Lattice Geometry Effects;132
16.3.3;7.3.3 Influence of Coronal Block Solvency;134
16.3.4;7.3.4 Solvophilic Block Length Effects;135
16.3.5;7.3.5 Colloidal Phase Stability of Spherical Micelles;136
16.4;7.4 Conclusions;138
16.5;References;139
17;8 Polymer-Mediated Stability of Micellar Suspensions;142
17.1;8.1 Introduction;142
17.2;8.2 System Parameters;144
17.3;8.3 Results and Discussion;145
17.3.1;8.3.1 Dilute Homopolymer in a Micellar Suspension;146
17.3.2;8.3.2 Depletion in ACPMs;148
17.3.3;8.3.3 Coronal Physisorption in ACPMs;151
17.3.4;8.3.4 Corona Thickness and Colloidal Stability;154
17.3.5;8.3.5 On the Phase Stability of ACPMs;155
17.4;8.4 Conclusions;157
17.5;References;159
18;Appendix About the Author;162