Swan
James W. Swan
1982-2021
James W. Swan passed away suddenly and unexpectedly November 5, 2021. He was 39. As a member of the rheology community, he had already made brilliant and foundational contributions to the fields of soft matter, colloid science, fluid mechanics, and computational modeling, with an increasing interest in societally relevant end-use applications of complex fluids. We recognized Jim for his extraordinary intellect. His original contributions to our field are notable for their breadth; his scholarship delved into topics related to the stability of biopharmaceutical formulations, the rheology of colloidal suspensions, new techniques for material characterization, nanoparticle self-assembly, colloid uptake in living plants, and electrokinetics. Little seemed to escape his curiosity and his remarkable talent for elucidation.
One advance Jim made stands out as particularly important: his development and application of fast Stokesian dynamics simulations. His novel computational method addressed a long-standing and critical need in the field to efficiently incorporate hydrodynamic interactions into large-scale simulations of colloidal suspensions, polymers, proteins, and other complex fluids. Jim developed a new algorithm that scales linearly with system size to calculate Brownian motion in hydrodynamically-interacting systems using an Ewald summation of the Rotne-Prager-Yamakawa (RPY) tensor. In practical terms, the method was faster and less computationally expensive than state-of-the art iterative schemes that preceded it, and it avoided the shortcomings of other implicit solvent approaches in the overdamped regime of Stokes flow that governs the dynamics and rheology of soft materials. However, the work stood out for its sheer intellectual achievement that demonstrated Jim’s gift for penetrating the core physics of a problem and his tremendous skills synthesizing rigorous and useful solutions. The results of the work, published as “Rapid sampling of stochastic displacements in Brownian dynamics simulations,” J. Chem. Phys. 146, 124116, 2017, is a beautiful expression of his insights and a masterful piece of scholarship.
Jim applied his simulations and theories to gain insight into the microscopic dynamics and mechanics that accompany colloidal glass and gel transitions, which are important in a fundamental sense and relevant to a wide range of industrial applications, spanning from coatings to the stability and shelf-life of consumer products. Jim and his students showed how much is missed when hydrodynamics are neglected: gel lines and percolation boundaries shift when the collective motion induced by hydrodynamics is accounted for (Soft Matter, 46, 9009-9019, 2015; Soft Matter, 12, 7670-7681, 2016), hydrodynamics fundamentally alter the normal modes of gels (Physical Review E, 97, 012608, 2018), and large scale anisotropies in sheared colloidal gels, of long-standing interest and a subject of intense debate, are properly understood (Journal of Rheology, 62, 405-418, 2018). Among my favorite papers from Jim’s group in this area is his work on the catastrophic collapse of quiescent colloidal gels—a problem that has long fascinated academic scientists and frustrated industrial practitioners of particle technology (Z. Varga, J. L. Hofmann, J. W. Swan, J. Fluid Mech. 856, 1014–1044, 2018). Here, simulations play the role of validating an elegant first-principles theory of streamer formation and erosion that also capture the key observations of published gel collapse experiments. The paper concludes with scaling predictions for the “blow up” time of a gel—when and how it will consolidate. This result is the first truly predictive theory of gel collapse. It is a comprehensive work of scholarship that develops theory, computation, and explains a puzzling phenomenon.
A native of Scottsdale, Arizona, Jim received his bachelor’s degree in chemical engineering from the University of Arizona in 2004. He then went to Caltech, where he earned a master’s degree in 2007 and a PhD in 2010, both in chemical engineering, under the mentorship of John Brady. After finishing his doctorate, Jim worked with me at the University of Delaware, where he directed our investigations of colloidal self-assembly on the International Space Station and helped to build and analyze new optical trapping experiments. He joined the chemical engineering faculty at MIT in 2012 as an assistant professor and had recently been promoted to the rank of associate professor. He was awarded tenure in July 2021.
At MIT, Jim was living his dream as a scholar-educator. He was beloved by students for his teaching. He taught Introduction to Chemical Engineering for several years to second term, first-year undergraduates; he was also the instructor for the department’s core required graduate course in numerical methods. For three years in a row, Jim won the MIT Chemical Engineering Graduate Teaching Award, an honor conferred by students. Training students was one of Jim’s greatest joys. He was keen to spend hours working out ideas on the whiteboard with his advisees, but Jim also carved out time to talk about non-technical sides of life and work with them, too.
Outside of his research and teaching, Jim was a loving husband and father who enjoyed spending time and activities with his wife of 17 years, Laura Swan, and their son Henry. Jim would cook, fish, and spend time outdoors, as well as do science experiments with Henry. The activities that sparked Jim’s interest over the years included quilting, photography, home-brewing, and self-publishing “The Really Big SCRABBLE Word List.” He often sought to master a topic that captivated him, as evidenced by the third-degree black belt that he held in karate. Jim was also an active member of his Arlington, Massachusetts community. Neighbors remember him for his thoughtful voice and as an articulate and supportive member of the Arlington and Hardy Elementary School communities. Jim was a patient listener and facilitator who believed in the transformative power and importance of civil discourse.
In addition to Laura and Henry, Jim is survived by his parents, Gregory Swan and Jeanine Blanchard; his stepmother, Paulette Swan; his stepfather, Tim Blanchard; a sister, Heather Evanoff; parents-in-law, Thomas and Betsy McPhee; sisters-in-law Diana McPhee and Lisa Grinnell; brother-in-law Andrew McPhee; and many aunts, uncles, and cousins.
Jim was regarded for his scholarship and intellectual contributions to our field, but he was also known as a wonderful speaker, teacher, and mentor, and especially for his generous spirit and kindness. He was quick to smile, to laugh, and to share his delight in creative ideas and projects. He was humble about his many talents. Jim was poised to become one of the great rheologists, chemical engineers, and scientists of his generation. He is sorely missed.
Eric Furst
September 2022