It is my great pleasure to write a brief description of the impressive career and persona of Sujit S. Datta, recipient of the 2023 Arthur B. Metzner Early Career Award of The Society
of Rheology. Sujit is an associate professor in the Department of Chemical and Biological Engineering at Princeton University. His citation reads:
For pioneering studies of 3D visualization and modeling of complex fluids in complex environments, showing how flows of soft and living matter are altered by the confinement and
structural disorder of many real-world settings, and for guiding development of new approaches to environmental remediation, energy production, agriculture, water security, and
biotechnology.
Professor Datta’s path to this award has been especially interesting, and it reflects the broad but thorough grounding in education he has received as well as his innate drive to
expand the boundaries of knowledge to which he contributes.
Sujit grew up in Toronto and is a Canadian citizen. During his middle- and high-school years his family lived in Abu Dhabi, where he attended an International School that provided
Sujit with both a strong academic foundation and culturally enriching experiences for which he continues to be grateful. He was eager to experience life in the United States, and
in 2004, he enrolled at the University of Pennsylvania, expecting to expand his knowledge of jazz music and to major in philosophy. It was after his initial year at Penn that the
first glimmer of today’s Sujit Datta emerged, ignited by an introductory course in university-level physics, during which philosophy was overtaken by physics and mathematics. He
credits this awakening to an exceptional professor in charge of the course and in whose lab Sujit spent time during the rest of his undergraduate career studying the quantum mechanical
behavior of carbon nanomaterials. By introducing Sujit to the world of research and scientific inquiry, this was an experience that has had a lasting impact on his career.
Sujit’s interest in research was intensified by meeting David Weitz at Harvard and learning about the fascinating properties of soft (or “squishy”) materials. Sujit started his
PhD research under Weitz by studying the rheology of emulsions and then moved on to mapping the dynamics of multiphase flows in 3D porous media using confocal microscopy to
uncover new features of the properties of immiscible liquid mixtures. During this period Sujit became aware of the enormous opportunities available in the study of complex fluids
in porous media. In particular, he points to the influence of a classic paper he discovered while he was a graduate student. The paper was coauthored by Metzner himself (R.J. Marshall
and A. B. Metzner, Ind. Eng. Chem. Fundamentals, 6, 393-400 (1967)), and it motivated some of the research Sujit later continued at Princeton.
During his PhD studies, Sujit also became aware of the importance of rheology in living systems. This motivated him to pivot for his postdoctoral studies to the field of biology.
He joined the laboratory of Rustem Ismagilov in Chemical Engineering at Caltech, as part of a collaboration with a team of biologists to study the gut microbiome. Sujit quickly
went from doing experiments in microfluidics to doing surgery on mice. Through the creative application of ideas and tools from soft matter to address questions in biology this
research eventually led to a new understanding of how dietary polymers in the gut influence the properties of its contents and its protective mucus lining. (See PNAS
113, 7041 (2016).)
Hence when Sujit arrived at Princeton in 2017 he was well prepared to launch his independent career along two parallel and occasionally intersecting paths. One is to study the
dynamics of complex fluids flowing through porous materials and to link microscale processes to macroscopic rheological behavior. The other is to use the tools and approaches of
rheology to study the dynamics of living microbial systems, not in liquid cultures as is typically done in the lab but, as Sujit describes it, “in the complex environments where
the cells live and work.”
With respect to flow through porous media, Sujit’s experimental expertise has allowed him to unravel the coupling between pore space geometry, fluid flow, and microstructural
deformation, and to show how the combination can in some cases lead to unusual macroscopic transport behavior. For example, Sujit and his coworkers discovered that flow of polymer
solutions through pore arrays can be unexpectedly bistable, stochastically switching between two distinct unstable flow states due to the interplay between elongation and relaxation
of polymers as they are advected between pores (Journal of Fluid Mechanics, 890, A2 (2020) and Physical Review Fluids, 6, 033304
(2021)). Another example is the anomalous increase in the macroscopic resistance generated during polymer flow through porous media, a phenomenon that had eluded explanation for more
than 50 years. (See the Metzner publication cited earlier.) Sujit’s lab established that the pore-scale onset of unstable chaotic fluctuations arising from flow-induced polymer elastic
stresses helps to generatethis strong increase in the flow resistance (Science Advances, 7, eabj2619 (2021)). These findings not only help to deepen
understanding of polymer solution flows, but they also provide quantitative guidelines to inform their applications at large scales. Sujit’s lab has used a similar approach to
unravel the dynamics of other complex fluids, such as immiscible fluid mixtures and colloidal dispersions, in porous media (e.g., Science Advances, 6,
eabc2530 (2020) and Physical Review Fluids, 6, 014001 (2021)). Building on these advances, Sujit is currently exploring how such flow behaviors can be
harnessed for improved solute mixing/dispersion and removal of trapped immiscible fluids (e.g., contaminants) from porous media.
Another example to which Sujit has paid special attention is the ultimate “soft” porous medium, viz., hydrogels. He and his coworkers have shown how polymer chemistry,
gel microstructure, and external constraints inherent in many natural environments control how hydrogel materials deform and fracture. (See e.g., Science Advances,
7, eabd2711 (2021) and Physical Review Letters, 123, 158004 (2019).)
I mentioned earlier Sujit’s interest in studying microbial systems in “real” spaces. An excellent example is his development of a method to interrogate bacteria, from the scale
of a single cell to that of an entire population in crowded 3D spaces similar to many of their natural habitats. Using this platform, Sujit and his coworkers have shown how
current understanding of bacterial transport, based on studies performed in bulk liquids, is incomplete. For example, he has elucidated ways in which confinement in a crowded
medium fundamentally alters how bacteria spread via motility or growth at both the single-cell and population scales, and he has developed mathematical models inspired by classic
ideas of transport processes and rheology to predict these behaviors. (See, for example, Nature Communications 10, 2075 (2019); Physical Review Letters,
128, 148101 (2022); PNAS 119, (43) e2208019119 (2022).) This work exemplifies an important frontier for our field in the use of principles
of rheology to shed light on the workings of complex living and active systems.
The Datta lab at Princeton is an exciting and bustling place occupied by students, postdocs, and visitors across different fields and at various stages of their careers. In his six
years, Sujit has advised 14 postdocs and 10 graduate students. One of the numbers of which he is most proud is the nearly 30 undergraduates who have worked with him, several of them
coauthoring refereed publications. Sujit’s emphasis on providing research opportunities for undergraduates reflects the pivotal influence his time in a physics lab at Penn has had
on his career.
Since its founding in 2009, the list of Metzner Early Career Awardees has proved to be a magnificent predictor of outstanding future leaders in our field. I’m certain the 2023 recipient
will be another member of that distinguished group.