Seminars

Seminar Series Sponsored by Shell

Shell Seminar Series

The Chemical and Biological Engineering Department at Colorado School of Mines is proud to continue hosting our renowned Seminar Series presented by Shell. Since 2012, our Seminar Series has featured a range of diverse voices from many of the top scholars and researchers in the fields of Chemical and Biological Engineering.

Our Seminar Series is designed to inspire both our students and faculty, spark new relationships, and serve as an environment for engaging discussions and sharing of ideas. Our Seminar Series allows us to further our goal of developing applied research solutions aimed at many of the most pressing problems facing our nation and planet.

All seminars are held Fridays in CTLM102 from 10 to 11 a.m., unless otherwise noted.

Upcoming Seminar Speakers Spring 2024

January 12, 2024

Peter Beltramo, University Massachusetts Amherst

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Peter Beltramo is an Assistant Professor in the Department of Chemical Engineering at UMass Amherst. He earned a BS in Chemical Engineering from the University of Pennsylvania in 2009 and a PhD in Chemical Engineering from the University of Delaware in 2014, where he studied the electrokinetics and self-assembly of colloidal suspensions.  Before starting at UMass Amherst in 2018, he completed a postdoc in Soft Materials at ETH Zurich.  At UMass, his lab studies interfacial soft matter in contexts ranging from membrane biophysics and biomimetic materials to particle stabilized emulsions and ordered 2D materials. His recent recognitions include the NSF CAREER Award, ACS-PRF Doctoral New Investigator Award, and a Lilly Teaching Fellowship at UMass Amherst.

Abstract

Interfacial Colloidal Interactions, Dynamics, and Assembly: From Biomembranes to Ordered 2D Material

Soft matter interfaces are ubiquitous across diverse technologies ranging from pharmaceuticals to chemical formulations. The presence of surfactant molecules or colloidal particles at fluid interfaces gives the interface distinct properties in response to flow, deformation, and external fields that must be measured, understood, and manipulated for desired functionalities. This talk will focus on colloidal interactions in two such systems: crowded artificial biological membranes and anisotropic particles at air-water interfaces.  In the first part of the talk, we discuss the effects of increasing concentration of model membrane inclusions in an artificial cell membrane on inclusion diffusivity and the apparent viscosity of the membrane. In the second part of the talk, we highlight our recent discovery that particle surface porosity severely attenuates the capillary attraction between colloidal ellipsoids at fluid interfaces, enabling the development of ordered anisotropic 2D monolayers. By monitoring the dynamics of two particles approaching one another, we find that porous particles exhibit a strikingly shorter-range capillary interaction potential.  Interferometry measurements of the fluid deformation surrounding a single particle quantitatively confirm the decrease in capillary interaction energy and point to roughness-induced changes to interfacial pinning as the mechanism for reduced attraction. Lastly, we show how this reduction in interparticle capillary attraction and alteration in interfacial pinning manifests in the overall 2D interfacial assembly of such particles, informing an approach for the development of anisotropically ordered 2D materials.   

January 19, 2024

Rajib Saha, University of Nebraska-Lincoln

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Rajib Saha is an associate professor and chair of the graduate program of the Department of Chemical Engineering at University of Nebraska-Lincoln. He got his BS in Chemical Engineering from Bangladesh University of Engineering & Technology and MS and PhD from the Department of Chemical Engineering at Penn State and did his postdoctoral training at the Department of Biology at Washington University in St. Louis. Currently, he leads the Systems and Synthetic Biology Laboratory at UNL that focuses on studying non-model microbes, microbial communities, plants, and human diseases. His research work is funded by NIH, NSF, USDA, Nebraska Corn Board, and Nebraska Energy Center. He has been awarded NIH Outstanding Early Career Investigator Award (MIRA) and NSF CAREER grant. He is also the recipient of 2022 UNL College of Engineering Edgerton Innovation Award and 2020 Penn State Early Career Alumni Recognition Award.

Abstract

Investigating Biological Systems with the Integration of Modeling and Data Analysis

Systems Biology is relatively a new concept in which a systems level approach is needed in order to get a wholesome view of any biological system. This talk will highlight how metabolic modeling and ‘omics’ data exploration/integration can attempt to explore some of the important questions in biology ranging from stress or pathogenic response  to the metabolic versatility.

January 26, 2024

Chris Snow, Colorado State University 

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Dr. Christopher Snow received a B.S. degree in Chemistry from MIT in 2001 and his Ph.D. in Biophysics from Stanford University in 2006. As a Howard Hughes fellow at Stanford, Dr. Snow studied the biophysics of protein folding using distributed computing. He worked with Frances Arnold at Caltech from 2006-2011 as a Jane Coffin Childs Fellow and a KAUST Research Fellow. Since coming to Colorado State University in 2011, he has led a combined computation and experimental laboratory with a significant focus on the design, engineering, and applications of biomolecular crystals.

Abstract

Application Prospects for Ultra-High-Precision Biomaterials

While engineered therapeutic proteins are already big business, we are interested in pioneering future applications for protein assemblies and materials that are much larger, yet still offer a precisely defined nanostructure. “Solid state” proteins that are embedded within engineered crystals can enjoy extraordinary functional enhancements such as resistance to proteases or extremes of temperature or pH. The explanation is simple — functional proteins that are anchored within a tough protein matrix can avoid unfolding and aggregation despite operating at unparalleled concentration. To avoid the technical challenge of forming crystals from diverse functional proteins, we instead grow scaffold crystals with large nanopores (>10 nm diameter) and stabilize these scaffolds using covalent crosslinks. The resulting “molecular pegboard” materials can capture and organize functional guest molecules with high precision, capacity, and stability. One of our families of scaffold crystals has an extremely high affinity to capture nucleic acids, which is enabling several biosurveillance applications. Lastly, the nanostructure of the material does not depend on the crystal size, which opens the door for structure-guided design of materials that offer tightly metered or triggered release of therapeutic macromolecules.

February 2, 2024

Kyle Bishop, Columbia University

Location: CTLM 102 Time: 10-11 a.m.

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 Bio

Kyle J. M. Bishop is Professor of Chemical Engineering at Columbia University. He received his BS in Chemical Engineering with highest distinction from the University of Virginia and his PhD from Northwestern University. Prior to joining the Columbia faculty in 2016, he was a post-doctoral fellow with George Whitesides at Harvard University and an Assistant Professor of Chemical Engineering at the Pennsylvania State University. His research seeks to discover, understand, and apply new strategies for organizing and directing the assembly of colloids and other soft materials outside of thermodynamic equilibrium. Bishop is the recipient of the 3M Non-tenured Faculty award and the NSF CAREER award. 

Abstract

Colloidal robotics: Engineering self-guided behaviors of active particles

Mobile robots combine sensory information with mechanical actuation to move autonomously through complex environments and perform specific tasks (e.g., a robot vacuum cleaner). The miniaturization of such robots to the size of living cells (ca. 2-40 mm) is actively pursued for applications in biomedicine, materials science, and environmental sustainability. In pursuit of these “microrobots”, we seek to understand the many mechanisms underlying the self-propulsion and assembly of colloidal particles through viscous fluids. Building on this understanding, we seek to design active particles capable of self-guided behaviors such as navigation of structured environments.  In this talk, I discuss two recent efforts – on Quincke oscillators and magnetic topotaxis, respectively – that highlight these complementary aims to understand and design active colloids. In part one, I explain how static electric fields drive the oscillatory motion of micron-scale particles and direct the formation of “living” crystals of finite size. In part two, I describe how spatially uniform, time-periodic magnetic fields can be designed to power and direct the migration of ferromagnetic spheres up local gradients in surface topography.

February 16, 2024

Talid Sinno, University of Pennsylvania

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Talid Sinno received his B.S. in Chemical Engineering and B.A. in Chemistry from the University of Pennsylvania. He received a Ph.D. (1998) in Chemical Engineering from M.I.T, where he subsequently spent another year as a postdoctoral researcher and lecturer. He has been a member of the faculty of the Department of Chemical and Biomolecular Engineering at the University of Pennsylvania since 1999 and is currently Professor of Chemical and Biomolecular Engineering. He holds a secondary appointment in the Department of Mechanical Engineering and Applied Mechanics at Penn. Talid also serves as the Founding Director of the Master’s Program in Scientific Computing (SCMP) at Penn, which provides students with training at the nexus of modern scientific computing and data science. Talid’s research in computational materials science is focused on multiscale modeling and simulation of nucleation, assembly, and crystallization processes in a wide range of material systems. Examples include semiconductor microstructure evolution during crystal growth and wafer processing, colloidal self-assembly, and platelet cell aggregation in blood flow. His group develops and applies numerous computational techniques across length and time scales to study these problems, including molecular dynamics, various flavors of Monte Carlo, and continuum modeling.

Abstract

The materials science of DNA-linked colloids: messy models for atomic systems?

The self-assembly of colloidal crystals from micro- or nano-particles is of interest as a potential avenue for making novel materials with unique optical and/or structural properties. A diverse range of ordered configurations have now been demonstrated using self-assembling particles driven by one or more of a number of strategies, including external fields, depletion, and functionalized particles. One particularly versatile approach is to functionalize particles with brushes of single-stranded DNA oligomers that are designed to partially hybridize with strands on other particles. These hybridization events collectively create an isotropic time-averaged interaction potential between particles, similar to those that exist between (simple) atoms. Careful design of the DNA oligomer sequence allows for the creation of distinct ‘elements’ and the spontaneous assembly of a diverse range of multicomponent crystalline structures. 

Numerous successful experimental demonstrations to date notwithstanding, it is now increasingly clear that a rigorous understanding of the materials science governing both the thermodynamics and kinetics of self-assembly is required in order to fully take advantage of this potentially powerful route for assembling interesting ordered (and disordered) configurations. In this talk, I describe work employing a several computational techniques to study the nucleation, growth, and structural transformations of colloidal crystals. First, I describe how intentional control of size mismatch between crystals may be used to create ‘floppy’ structures with interesting degrees of freedom that enable so-called diffusionless transformations. The unexpected, yet important, role of hydrodynamic correlations between colloids in this setting will be discussed. Next, a study of heterogeneity in the interactions between particles is presented that shows how a seemingly detrimental aspect of the DNA-functionalization process can in fact increase crystallization robustness. Togther, these phenomena highlight the fact that, while colloidal systems are frequently considered as useful models for atomic behavior, they are also subject to their own interesting peculiarities.

February 23, 2024

Symone Alexander, Auburn University

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Dr. Symone Alexander is an Assistant Professor in the Department of Chemical Engineering at Auburn University. Prior to her role at Auburn University, she was an Eckert Postdoctoral Research Fellow at Georgia Institute of Technology in the Department of Chemical and Biomolecular Engineering, she led investigations on extreme organismic biophysics with a focus on ultra-fast motion in nature in Prof. Saad Bhamla’s research group. She earned her Ph.D. in Macromolecular Science and Engineering as an NSF Graduate Research Fellow at Case Western Reserve University, advised by Prof. LaShanda Korley. During her graduate career, she led research on the influence of high molecular weight polymers on self-assembling small molecules and how those networks can be utilized to generate bioinspired, responsive polymer composites. She obtained a B.S. in Chemical Engineering from Howard University in 2013, where she investigated DNA-polymer assemblies utilizing Atomic Force Microscopy under the advisement of Dr. Preethi Chandran and Dr. Joseph Cannon.

 Dr. Alexander is a recipient of numerous awards and honors, including a 2023 AFOSR Summer Faculty Fellowship, grad and postdoc fellowships, selection as a 2020 Emerging Leader by Georgia Tech Dept. of Mechanical Engineering, selection as a 2019 American Chemical Society Future Faculty Scholar (ACS PMSE), and being selected as a 2018 Rising Star in Chemical Engineering by the Massachusetts Institute of Technology (MIT).

Abstract

Extraction and utilization of biopolymers from food waste

The Alexander Research Team uses nature as inspiration for everything we do – from reverse engineering biological systems for engineering design to using self-assembly and structural hierarchy to access new material properties. In recent years, there has been a shift to utilize biopolymers, such as cellulose, in the production of many different materials. These biopolymers are in abundance and found naturally in plants. The goal of our work is to design sustainable, environmentally friendly platforms to extract biopolymers from real-world, mixed food and agricultural waste that can be utilized in many different applications.  Using food waste as a feedstock for our processes and material design decreases waste being placed into landfills and ultimately helps drive down the emission of greenhouse gases. Our work emphasizes the importance of the sustainability goals of the UN, including climate action, industry, innovation, and infrastructure.

Dale Erickson Headshot

March 29, 2024

Will Smith, A123 Systems 

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Dr. Will Smith received his B.S. in Chemical Engineering from Kansas State University in 2018 and his Ph.D. in Chemical Engineering from the Colorado School of Mines in 2023. At the School of Mines, he worked under Professor Colin Wolden on the synthesis of metal sulfide compounds for solid-state battery applications using metathesis reactions, for which he received the Award for Outstanding Thesis in Chemical Engineering. In 2023 he began work as a Research Scientist at A123 Systems where he is developing long-life lithium-ion batteries for stationary energy storage systems.

Abstract

Metathesis Synthesis of Metal Sulfide Compounds for Solid-State Battery Applications

Solid-state batteries hold promise for improved energy density and safety compared to conventional lithium-ion batteries. A promising class of inorganic solid electrolytes (SEs) are the sulfide-based materials due to their high lithium-ion conductivity and ease of processing. However, the cost of the requisite metal-sulfide precursors constrains the large-scale production of sulfide-based SEs. In this talk, I will present scalable approaches to synthesize precursors – in particular Li2S and SiS2 – from metathesis reactions of Na2S and metal salts. First, the production and purification of Na2S – a key reagent in metathesis reactions – will be presented. Next, I will present the metathesis synthesis and subsequent purification of Li2S from low-cost Na2S and LiCl. Finally, I will introduce the concept of cascaded metathesis. Li2S is a powerful reagent for metathesis that can be used to synthesize nearly any metal sulfide, including those that are unstable in protic solvents. Cascaded metathesis refers to the process in which these reactions are coupled to the first metathesis reaction, LiCl and solvents are recycled and reused, resulting in metal sulfide synthesis from low cost Na2S and metal halide salts. Cascaded metathesis was demonstrated through the first solution-based synthesis of SiS2.

April 5, 2024

Masaru K. Kuno, University of Notre Dame

Location: CTLM 102 Time: 10-11 a.m.

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Bio 

Professor Kuno did his undergraduate studies at Washington University in St. Louis. He then completed a PhD at MIT with Moungi Bawendi, working on the band edge spectroscopy of CdSe quantum dots. This was followed by a NRC postdoctoral fellowship at JILA/NIST/University of Colorado at Boulder with David Nesbitt. Professor Kuno followed this with a research stint at the US Naval Research Laboratory in Washington DC before coming to Notre Dame in 2003. He is the author of two books: Introductory Nanoscience: Physical and Chemical Concepts and Introductory Science of Alcoholic Beverages. Beer, Wine, and Spirits.

Abstract

The band edge absorbing and emitting states of CsPbBr3 nanocrystals

Perovskite nanocrystals (NCs) such as those made from CsPbBr3 have numerous uses. Most involve exploiting their light emission and are motivated by their defect tolerance and large, as-made emission quantum yields (QYs). For the latter, near unity QYs are possible. This leads to ready applications as light emitters but also intriguingly to possible material platforms for demonstrating semiconductor-based optical refrigeration.

 Absent, though, is a fundamental understanding of perovskite NC emitting states, central to these applications. Of particular note are observations of near-universal, size-, temperature-, and composition-dependent absorption/emission Stokes shifts where observed energy differences are those that separate absorbing and emitting states. Moreover, efficient (near-unity efficiency), photoluminescence up-conversion, induced by exciting NCs below gap, motivates better understanding the microscopic nature of perovskite band edge states.

 I will explain work we have done recently within the context of attempts to optically refrigerate a semiconductor. These studies now provide new insight into the band edge states of CsPbBr3 (and possibly CsPbX3) NCs. Starting with a microscopic mechanism for explaining how it is possible to obtain efficient, near-unity efficiency photoluminescence up-conversion to we extend the conclusions of these measurements to explain the origin of observed, size-dependent absorption/emission Stokes shifts. Here, despite some initial studies we and others have conducted, very little is known about their true origin. This is to be contrasted to more conventional NCs such as CdSe where band edge exciton fine structure quantitatively accounts for both global and resonant Stokes shifts, with emission emerging from a dark exciton. Although similar perovskite NC fine structure might account for their shifts, both theory and experiment predict bright/dark fine structure splittings easily an order of magnitude too small to account for experiment.

We now propose that perovskite NC emitting states are polarons, which result from the lattice accommodation of photogenerated charges. Polaron binding energies and lifetimes are, in turn, suggested to be the origin of observed l-, T-, and composition-dependent absorption/emission Stokes shifts and excited state lifetimes. This represents a significant departure from more conventional descriptions of NC band edge states, which exclusively involve exciton fine structure and dark exciton emitting states.

April  19, 2024

George Nolas, University of South Florida

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Dr. George S. Nolas is Distinguished University Professor of Physics at the University of South Florida. His research interest focuses on materials physics, and areas such as new materials synthesis and characterization, nano-scale properties of material, slow temperature electrical and thermal transport, structure-property relationships, and energy technologies. He is a Fellow of the American Association for the Advancement of Science (AAAS), and the American Physical Society. He was elected as an AAAS Fellow for contributions to materials and solid-state physics, particularly for the development of thermoelectric materials, and in investigating the fundamental physics of clathrate and clathrate-like materials. He is a charter member of the National Academy of Inventors (NAI) and serves on the Executive Committee of the USF Chapter of the NAI.

Abstract

Structure and properties of complex chalcogenides: Fundamental research with an eye towards applications.

Complex chalcogenides have a variety of properties, many of which are of interest for different technological applications. Research into new materials expands our library of materials and provides potential new avenues for discovery, as well as allows for the design of materials or processing techniques with targeted properties of interest. The intellectual merit of these investigations is very closely tied to developing a fundamental understanding of the underlying physical properties and their structure-property relationships. I will present some of our recent progress on the structure-property relationships of specific materials, including new quaternary chalcogenides, provide insight into the search for new materials, and present results that demonstrate unique thermal  properties and transport in chalcogenide materials.

April  26, 2024

Karen Winey, University of Pennsylvania

Location: CTLM 102 Time: 10-11 a.m.

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Bio

Karen I. Winey is the Harold Pender Professor of Engineering and Applied Science at the University of Pennsylvania with a 50:50 appointment between Chemical and Biomolecular Engineering and Materials Science and Engineering.  Karen received her B.S. in materials science from Cornell University, earned her Ph.D. in polymer science and engineering from the University of Massachusetts, Amherst, and joined the Penn Engineering faculty have a brief postdoc at AT&T Bell Labs.  Karen has made significant contributions in the to the field of polymer science, particularly in the understanding of and manipulation of unique polymer nanocomposites and ion-containing polymers.  Her primary focus is hierarchical and nanoscale morphologies in polymers which she connects to the underlying chemical structure as well as the mechanical, thermal and transport properties.  In addition to earlier recognitions, Karen was recently awarded the 2020 Braskem Award by AIChE, fellowship in the American Association for the Advancement of Science in 2022, and the 2023 ACS Award in Polymer Chemistry.

Abstract

Self-Assembled Water Channels in Fluorine-Free Polymers for Fast Proton Conductivity

 While perfluorosulfonic acid polymers are widely used as proton-exchange membranes (PEMs), concerns arising from fluorine have stimulated interest in hydrocarbon-based PEMs. In previous work, we studied a linear polyethylene with a phenylsulfonic acid pendant group precisely on every fifth carbon and found the proton conductivity to exceed 0.1 S/cm above 65% relative humidity at 40 C. This study explores related polymers with lower sulfonations levels to improve the processability and mechanical properties. By combining novel synthesis, X-ray scattering, FT-IR spectroscopy, pulse-field gradient NMR, electrochemical impedance spectroscopy, and all-atom molecular dynamics simulations, we are establishing design rules to produce nanoscale water channels with high proton conductivity. From the simulations we extract quantitative information about the self-assembled water channels in the hydrated polymers via cluster analysis, channel width distributions, surface area per sulfonate group, and fractal dimensions. From the spectroscopy methods, we probe the local structure and relaxations of water in the hydrated membranes. Notably, a moderate reduction in sulfonation level enhances the mechanical toughness while maintaining high proton conductivity in these new fluorine-free PEMs.