University of Groningen
Dynamics of self-propelled colloids and their application as active matter Choudhury, Udit
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Publication date: 2019
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Choudhury, U. (2019). Dynamics of self-propelled colloids and their application as active matter. University of Groningen.
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Dynamics of self-propelled colloids
and their application as active matter
faculty of mathematics and natural sciences
university of
groningen zernike insitute for advanced materials
The research presented in this thesis was performed in the Max Planck Institute for Intelligent Systems, Germany and the Zernike Institute for Advanced Materials at the University of Groningen, The Netherlands.
Zernike Institute PhD thesis series 2019-06 ISSN: 1570-1530
ISBN: 978-94-034-1363-1 (Printed version) ISBN: 978-94-034-1362-4 (Electronic version) Print: Studentendrukwerk, Groningen
Contents
1 INTRODUCTION TO ACTIVE COLLOIDS 1
1.1 COLLOIDS AT LOW REYNOLDS NUMBER 2
1.2 PHORESIS AND SELF-PHORESIS 3
1.3 FABRICATION OF COLLOIDS WITH GLANCING ANGLED DEPOSITION 5
1.4 REFERENCES 10
2 PHYSICAL VAPOR DEPOSITION FABRICATED NANOSCALE SURFACE PATTERNS
INCREASES SPEED FOR ACTIVE JANUS MICROMOTORS 14
2.1 INTRODUCTION 15
2.2 MOTIVATION 15
2.3 RESULTS 17
FABRICATION OF JANUS PARTICLES 17
2.3.1
OXYGEN EVOLUTION TEST 20
2.3.2
SWIMMING OF ROUGH AND SMOOTH JANUS PARTICLES 21
2.3.3
THEORETICAL FIT TO SELF-DIFFUSIOPHORETIC MODEL 28
2.3.4
2.4 DISCUSSION 29
2.5 REFERENCES 32
2.6 APPENDIX 34
MEAN SQUARED DISPLACEMENT OF A SPHERICAL CATALYTIC SELF-PROPELLED COLLOID 34
2.6.1
3 ACTIVE COLLOIDAL PROPULSION OVER A CRYSTALLINE SURFACE 35
3.1 INTRODUCTION 36
3.2 MOTIVATION 36
3.3 RESULTS 38
3.3.2 DATA ANALYSIS 39
3.3.3 HEIGHT OF THE POTENTIAL BARRIER 39
3.3.4 DISTANCE FROM TOP OF SURFACE 42
3.3.5 ACTIVE MOTION ON A PLANE AND ENHANCED DIFFUSION 44
3.3.6 ACTIVE MOTION ON CRYSTALLINE SURFACE 46
3.4 DISCUSSIONS 50
3.5 REFERENCES 52
3.6 APPENDIX 56
3.6.1 MEAN-SQUARE DISPLACEMENT OF A SELF-PROPELLED PARTICLE ATOP A CRYSTALLINE SURFACE 56
4 NANODIAMONDS THAT SWIM 58
4.1 INTRODUCTION 59 4.2 MOTIVATION 60 4.3 RESULTS 61 4.3.1 DESIGN OF ND SWIMMERS 61 4.3.2 FABRICATION OF ND SWIMMERS 63 4.3.3 MOTION OF ND SWIMMER 66
4.3.4 ELECTRON SPIN RESONANCE OF ND SWIMMERS 70
4.4 DISCUSSION 73
4.5 EXPERIMENTAL SECTION 75
4.5.1 SAMPLE PREPARATION 75
4.5.2 FLUROSCENCE IMAGING 76
4.5.3 SIGNAL PROCESSING AND TRACKING 76
4.5.4 RF CIRCUIT INTEGRATION 76
4.6 REFERENCES 78
4.7 APPENDIX 81
5 CHEMICAL NANOMOTORS AT THE GRAM SCALE FORM A DENSE ACTIVE
OPTO-RHEOLOGICAL MEDIUM 82
5.1 INTRODUCTION 83
5.2 MOTIVATION 84
5.3 RESULTS 85
5.3.1 NON-EQUILIBRIUM MICRO-STRUCTURAL EVOLUTION 88
5.3.2 MICRO-RHEOLOGY OF AN ACTIVE SUSPENSION 93
5.3.3 BULK RHEOLOGY OF AN ACTIVE SUSPENSION 96
5.4 DISCUSSION 100
5.5 EXPERIMENTAL METHODS 101
5.5.1 COLLOIDS 101
5.5.2 DYNAMIC DIFFERENTIAL MICROSCOPY 101
5.5.3 MICRO-RHEOLOGY 102 5.5.4 BULK RHEOLOGY 102 5.6 REFERENCES 103 6 CONCLUSIONS 107 6.1 CONCLUSIONS 108 7 SUMMARY 110 7.1 SUMMARY 111 8 SAMENVATTING 114 8.1 SAMENVATTING 115
9 CURRICULUM VITAE AND PUBLICATIONS 118
