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Nanoparticle Diffusion in Polymer Networks University of Pennsylvania ScholarlyCommons Publicly Accessible Penn Dissertations 2017 Nanoparticle Diffusion In Polymer Networks Emmabeth Parrish Vaughn University of Pennsylvania, [email protected] Follow this and additional works at: https://repository.upenn.edu/edissertations Part of the Mechanics of Materials Commons, and the Nanoscience and Nanotechnology Commons Recommended Citation Vaughn, Emmabeth Parrish, "Nanoparticle Diffusion In Polymer Networks" (2017). Publicly Accessible Penn Dissertations. 3073. https://repository.upenn.edu/edissertations/3073 This paper is posted at ScholarlyCommons. https://repository.upenn.edu/edissertations/3073 For more information, please contact [email protected]. Nanoparticle Diffusion In Polymer Networks Abstract The incorporation of nanoparticles into polymer networks can lead to improvements in current technologies and solutions for global challenges. For example, mechanical properties can be enhanced while maintaining processability, controlled release of drugs can be enabled, and desalinization membrane capabilities can be improved. Inherent to these applications is controlling the localization and mobility of nano-scale diffusants. To improve the functionality of polymer nanocomposite materials, a fundamental understanding of how polymer parameters affect nanoparticle diffusion is required. For this dissertation, I studied nanoparticle diffusion within heterogeneous, homogenous, and biological polymer networks. Using single particle tracking, I investigated the role of confinement, heterogeneity, extent of gelation, and swelling on nanoparticle mobility. For each study, nanoparticles were integrated into the polymer network, hundreds of trajectories were followed in fast frame rate videos, and then these trajectories were analyzed to yield quantitative information such as mean-squared displacement, displacement distributions, and diffusion coefficients.r F om quantitative analysis of nanoparticle dynamics, insight into the impact of various polymer properties on mobility were obtained. Specifically, in two environmentally responsive, heterogeneous hydrogels, polyacrylamide and poly(N- isopropylacrylamide) gels, confinement, dynamic heterogeneity, and enthalpic interactions impacted nanoparticle mobility, which varied from diffusive to localized. Solvents and temperature were used to elicit collapse of these heterogeneous networks, which resulted in drastically decreased nanoparticle mobility. In these studies, displacement distributions revealed the extent of Gaussian behavior which was found to be a marker of environmental heterogeneity or cage size. For gelation of tetra-poly(ethylene glycol) networks, a proposed homogeneous network, polymer concentration and extent of gelation impacted nanoparticle diffusion. Using analytical tools developed for synthetic polymer networks, nanoparticle diffusion within the cell cytoplasm was studied, revealing that nanoparticles moved further and faster in cancerous cells and in cells with disrupted actin networks. Overall, our studies revealed that confinement alone does not control nanoparticle mobility within polymer networks and that dynamic heterogeneity played a significant ole.r Identifying factors which determine how nanoparticles diffuse in polymer networks will aid in the design of novel and existing membranes, scaffolds, and drug delivery systems. Degree Type Dissertation Degree Name Doctor of Philosophy (PhD) Graduate Group Materials Science & Engineering First Advisor Russell J. Composto Keywords hydrogels, intracellular diffusion, nanoparticle diffusion, non-Gaussian displacements, single particle tracking, volume phase transition Subject Categories Mechanics of Materials | Nanoscience and Nanotechnology This dissertation is available at ScholarlyCommons: https://repository.upenn.edu/edissertations/3073 NANOPARTICLE DIFFUSION IN POLYMER NETWORKS Emmabeth Parrish Vaughn A DISSERTATION in Materials Science and Engineering Presented to the Faculties of the University of Pennsylvania in Partial Fulfillment of the Requirements for the Degree of Doctor of Philosophy 2017 Supervisor of Dissertation ________________ Russell J. Composto Professor of Materials Science and Engineering Graduate Group Chairperson ________________ David Srolovitz Professor of Materials Science and Engineering Dissertation Committee Karen I. Winey, Chair and Professor of Materials Science and Engineering Zahra Fakhraai, Associate Professor of Chemistry Daeyeon Lee, Professor of Chemical and Biomolecular Engineering NANOPARTICLE DIFFUSION IN POLYMER NETWORKS COPYRIGHT 2017 Emmabeth Parrish Vaughn This work is licensed under the Creative Commons Attribution- NonCommercial-ShareAlike 3.0 License To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/3.0/us/ To my mother and to those I mother, for the encouragement of science to and through women iii ACKNOWLEDGMENT Within my research advisor’s thesis is an excerpt from Luke 12:48 which says, “To whomsoever much is given, of him shall much be required.” Indeed Dr. Composto has given me much over the past five years. He has given me numerous research ideas and the guidance to help make many of those ideas fruitful. He gave me the opportunity to travel to France to learn a different way of doing science. He has also given me opportunities for teaching and scientific outreach. He recommended me for a Center for Teaching and Learning Fellowship, encouraged me to participate in Girls in Engineering, Math, and Science (GEMS) and other outreach events, and allowed me to be the T. A. for his class for 2 years as well as guest lecturer in subsequent years. I came into graduate school with the desire to teach as my career; I am truly fortunate that he values teaching. Thank you Dr. Composto for each of these gifts. I would also like to thank my thesis committee for their gifts of time, education, and wisdom. Both Dr. Lee and Dr. Winey gave me the best classes I took at Penn. I would not be able to consider myself a polymer physicist without these classes and their instruction. Dr. Winey has also given me valuable feedback on my work throughout my time at Penn through MWN and other subgroup meetings. Dr. Fakhraai always has advice on whose work I should be reading at my committee updates, and has been instrumental in facilitating many of the Penn Polymer group activities. In fact, each member of my committee has been involved with the Penn Polymer group which has given me both a space to internally give talks and posters and a network of peers to work alongside; for that I am very thankful. A highlight of my time at Penn was the year I spent as a Center for Teaching and Learning (CTL) Fellow. Bruce Lenthall, Ian Petrie, Catherine Turner, and everyone else at CTL helped me shape the way I think about teaching. Ian was particularly influential on my own teaching, despite the differences in our fields (his is history). I met with Ian and a group of other graduate students from disciplines all over campus every two weeks to discuss our teaching, other people’s effective teaching methods, and best practices in education. I also took a short summer course on evidence-based teaching methods from Ian which solidified my interest in engineering education research. iv I am thankful for the support staff of both the department and facilities. Pat Overend, Irene Clements, and Vicky Lee have helped me with room booking, scanning documents, and lifting my spirits by telling me they liked my outfit. Matt Brukman has helped maintain the inverted microscopy equipment which I used to complete most of my thesis work. Also, Doug Yates and Jamie Ford taught me how to use the Ion Beam and FIB SEM and generally keep equipment in amazing shape. My peers in the Composto group have been an invaluable source of scientific knowledge, sympathetic ears, and friendship. When I joined the group, the members that came before me, especially Rob Ferrier and Jim Lin, were always available to answer any science or Philadelphia questions I had. Jim thought of me when he wanted to add nanoparticle diffusion to the perspective he was writing, which has really boosted my Google Scholar page! Rob always made me feel like I was capable of actually completing this degree, no easy task. The post docs in our lab have also been integral to me completing my thesis. Hyun-Su Lee was our chemistry guru. Jihoon Choi showed me how to collect ion beam data. Carme Coll-Ferrer taught me about being safe in lab while pregnant, well before I knew how important that would be. Prathima Nalam taught me how to make colloidal AFM tips, which I did not use for my own research, but was able to provide to many collaborators. I am grateful for my collaboration with Martha Grady which resulted in Chapter 6. We also had many fruitful conversations regarding the importance of teaching and mentorship. The current members of the Composto group, Boris Rasin, Ben Lindsay, Nadia Krook, Katie Rose, Yuanchi Ma, Shawn Maguire, Sarah Seeger, Carlos Medina, and Teddy Kurkoski, are gems. Boris makes sure you question everything and always has a thought to share. Yuanchi and Katie are working on projects that are extensions of this thesis work, and it has been enriching to work with them. Katie also provides the office with lots of snacks, which has been particularly great while nursing! Shawn and Katie also took over management of the website. If I were a prospective student, I would join our group based on it. Ben provides a computationalist’s view to group
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