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Understanding Nanoparticle Aggregation Gaurav Pranami Iowa State University

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Understanding Nanoparticle Aggregation Gaurav Pranami Iowa State University Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2009 Understanding nanoparticle aggregation Gaurav Pranami Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Biological Engineering Commons, and the Chemical Engineering Commons Recommended Citation Pranami, Gaurav, "Understanding nanoparticle aggregation" (2009). Graduate Theses and Dissertations. 10859. https://lib.dr.iastate.edu/etd/10859 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Understanding nanoparticle aggregation By Gaurav Pranami A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Major: Chemical Engineering Program of Study Committee: Monica H. Lamm, Co-major Professor Balaji Narasimhan, Co-major Professor R. Dennis Vigil Mark S. Gordon Shankar Subramaniam Sriram Sundararajan Iowa State University Ames, Iowa 2009 Copyright © Gaurav Pranami, 2009. All rights reserved. TABLE OF CONTENTS ACKNOWLEDGMENTS……………………………………………………………………………. iv ABSTRACT…………………………………………………………………………………………… v CHAPTER 1: INTRODUCTION……………………………………………………………………... 1 Introduction ............................................................................................................................. 1 References ............................................................................................................................... 3 CHAPTER 2: RESEARCH OBJECTIVES…………………………………………………………… 4 Introduction ............................................................................................................................. 4 Specific Goal 1: Forces between PS Micro- and Nanoparticles Using AFM ......................... 5 Specific Goal 2: Systematic Goarse-Graining for Multiscale Modeling ................................. 7 Specific Goal 3: Diffusion of Fractal Aggregates ................................................................... 9 Conclusion ............................................................................................................................. 10 References ............................................................................................................................. 10 CHAPTER 3: LITERATURE REVIEW…………………………………………………………….. 12 Atomic Force Microscopy ..................................................................................................... 12 Systematic Coarse-Graining Techniques .............................................................................. 23 Diffusion of Fractal Aggregates ............................................................................................ 35 References ............................................................................................................................. 40 CHAPTER 4: MEASURING FORCES BETWEEN POLYSTYRENE MICRO- AND NANOPARTICLES USING ATOMIC FORCE MICROSCOPY…………………………………... 47 Abstract ................................................................................................................................. 47 Introduction ........................................................................................................................... 47 Materials and Methods .......................................................................................................... 50 Results and Discussion .......................................................................................................... 56 Conclusions ........................................................................................................................... 61 Acknowledgements ............................................................................................................... 62 References ............................................................................................................................. 62 CHAPTER 5: COARSE-GRAINED INTERMOLECULAR POTENTIALS DERIVED FROM THE EFECTIVE FRAGMENT POTENTIAL: APPLICATION TO WATER, BENZENE, AND CARBON TETRACHLORIDE……………………………………………………………………… 65 Abstract ................................................................................................................................. 65 Introduction ........................................................................................................................... 65 Theory ................................................................................................................................... 69 Computational Details ........................................................................................................... 76 Results and Discussion .......................................................................................................... 80 Conclusions ........................................................................................................................... 88 Acknowledgements ............................................................................................................... 89 References ............................................................................................................................. 89 iii CHAPTER 6: MOLECULAR DYNAMICS SIMULATION OF FRACTAL AGGREGATE DIFFUSION………………………………………………………………………………………….. 93 Abstract ................................................................................................................................. 93 Introduction ........................................................................................................................... 93 Computational Details ........................................................................................................... 99 Results and Discussion ........................................................................................................ 105 Conclusions ......................................................................................................................... 111 Acknowledgments ............................................................................................................... 112 References ........................................................................................................................... 113 CHAPTER 7: STATISTICAL ERROR IN THE PROPERTIES DERIVED FROM TIME CORRELATION FUNCTIONS FROM MOLECULAR DYNAMICS SIMULATIONS………… 115 Abstract ............................................................................................................................... 115 Introduction ......................................................................................................................... 115 Computational Details ......................................................................................................... 117 Statistical Uncertainty ......................................................................................................... 119 Results and Discussion ........................................................................................................ 119 Need for conducting MIS .................................................................................................... 123 Conclusions ......................................................................................................................... 127 Acknowledgments ............................................................................................................... 128 References ........................................................................................................................... 128 CHAPTER 8: CONCLUSIONS AND FUTURE WORK………………………………………….. 129 iv ACKNOWLEDGMENTS I would like to express my sincere thanks to my advisors, Profs. Monica H. Lamm and Balaji Narasimhan for their guidance, encouragement and advice during my doctoral research at Iowa State University. I would also like to thank Profs. R. Dennis Vigil, Mark S. Gordon, Shankar Subramaniam and Sriram Sundararajan for their guidance and for serving on my graduate committee. I learned a great deal from candid discussion on my research with Drs. Curtis Mosher and Warren Straszheim, Lyudmila Slipchenko and with my former group mates Drs. Nick Suek, Rastko Sknepnek and Yin Yani. I am grateful for all the opportunities that I got at Iowa State University that have helped me grow into a better individual. I would like to acknowledge my friends Latrisha, Keenan, Sikki, Matt, Al and Lori who made this journey fun and memorable. I consider myself to be lucky to have found my girlfriend Sarah, and I am thankful for her immense support and unconditional love. Last but not the least, I want to acknowledge my family, especially my mother and sister. They are the rock that I stand on to reach for my dreams and without them nothing means anything. As I move on in my life, I will try to do the best I can without losing sight of what I learned at Iowa State. v ABSTRACT Nanoparticles form the fundamental building blocks for many exciting applications in various scientific disciplines. However, the problem of the large-scale synthesis of nanoparticles remains challenging. It is necessary to understand the nanoparticle aggregation for the rational design of reactors
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