Spring 2022

Departmental Seminars

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January 10, 2022
10:30 AM
EB1 Room 1011
Dr. Peter Vekilov
University of Houston
Often, available data on the reaction mechanisms are employed to model and engineer the rates and outcomes of chemical processes. We enforce a flow of information in the opposite direction. I will discuss two examples, in which we use reaction rates measured under carefully controlled conditions to deduce intimate details about the molecular motions that manifest macroscopically as aggregation and crystallization.The accumulation of fibrils and plaques of the amyloid beta peptide is a hallmark and the likely cause of Alzheimer’s disease and related neuropathies. Ab fibrillization is an exceedingly complex process, in which the conformational transformations of the peptide chains integrate with fibril nucleation, growth, fractionation, and branching to form a network of intertwined events. We posit that the tips of the growing fibrils are the Achilles heel of fibrillization to be targeted by additives that may rise to potential Alzheimer’s drugs. We pioneer the use of time-resolved in situ atomic force microscopy to monitor the responses of the fibril growth rate to the thermodynamic driving force and the presence of a denaturant. The AFM results, concurrently with molecular simulations, advocate that a complex comprised of three or four peptide chains in non-native conformations crowns the fibril tips and governs the rate of incorporation of incoming peptide monomers. We show that drug induced restructuring of this frustrated complex may be a successful strategy to stunt fibril growth.Molecular crystallization rests at the core of physiological, geological, and industrial processes. Attempts to predict a priori crystal growth rates and their anisotropy, which control the sizes and aspect ratios of the crystal populations, often fail owing to the poor understanding of the constituent molecular processes. Time-resolved in situ AFM measurements, complemented by all-atom MD modeling, reveal that the egress of a solute molecules into a crystal growth site, a kink, proceeds in two steps. The stability of the intermediate state is administered by the solvent – solute – kink interactions. The proposed two-step scheme of molecular incorporation presents a new paradigm for solution crystallization that may contribute to understanding crystallization in nature and expedite the selection of solutes and solvents in the crystallization process design of organic pharmaceuticals and advanced materials.
January 19, 2022
10:30 AM
EB1 Room 1011
Dr. De-En Jiang
University of California, Riverside
My group is interested in both knowledge- and data-driven design of functional molecules and materials in chemical separations, nanocatalysis, and electric energy storage from a computational perspective. In this talk, I will first discuss several design approaches to tune and control pore size to achieve desired gas separation performances via graphene membranes. Concepts of ion-gating and entropy selectivity will be demonstrated via molecular simulations. Next, I will talk about porous carbonaceous materials for carbon capture; here we show that the 77K-N2-adsorption isotherms of porous carbons can be used as direct input to train convolutional neural networks for prediction of gas separation performance and to explore much broader porosity space. In the third topic, I will show an exciting progress in atomically precise metal-hydride nanocluster catalysts where the challenge to locate the hydrides was addressed by deep neural networks. In each of the studies, one will see a close interplay between computation and experiment, demonstrating that computation or an experiment in silico is now a valuable tool to drive advances chemical separations and catalysis.

January 19, 2022
5:00 PM
FWH Room 2336
Dr. Jason Smith
IP Group, Inc.
One of the most compelling challenges for government and society is the translation of billions of dollars in government research investment into benefits for humanity. Often referred to as the valley of death, the complex interface of knowledge, expertise and motivation between academia and the commercial world is undergoing a period of rapid transformation. On the front line, there is a critical need for individuals that speak the language of both sides that are motivated to bridge the gap. This isn’t an end of career look back at how we figured it all out. This is a mid-career snapshot likely to generate as many questions as answers. I plan to share how I wound my way from a postdoc to the valley of death, why I’m more excited than ever about the potential of NC State scientists to change the world, and some lessons learned along the way. I understand there will also be free pizza!

January 24, 2022
10:30 AM
EB1 Room 1011
Dr. Vibha Kalra
Drexel University 
Rechargeable batteries with conversion type electrodes are attractive due to their ability to achieve higher capacity through multi-electron transfer reactions. Elemental sulfur is one of the most interesting materials amongst all conversion-based cathodes because of its high theoretical capacity (~1675 mAh/g – 5-10-fold higher than Li-ion batteries), natural abundance, non- toxicity, and cost-effectiveness. In this talk, I will present our group’s research on integrating material design and fabrication, in-operando and postmortem spectroscopy, and device assembly and testing to study and develop next generation lithium-sulfur batteries.
January 26, 2022
10:30 AM
EB1 Room 1011
Dr. Artem Rumyantsev
University of Chicago
Electrostatically driven phase separation in solutions of the oppositely charged polyelectrolytes (referred to as complex coacervation) and solutions of polyampholytes (called self-coacervation) is currently viewed as the basic physical model describing intracellular organization and the formation of membrane-less organelles. Coulomb attractions between the opposite charges within the polymer-rich phase are due to their positional correlations, and statistical physics of ionic polymers can be fruitfully applied to gain valuable insight into these phenomena. First, I will focus on how the equilibrium and dynamics properties of polymer-rich complex coacervate phases are affected by (i) salt concentration, (ii) solvent quality, (iii) stiffness of polyelectrolytes, (iv) their incompatibility, and (v) sequence of ionic and neutral monomers in them. I will then discuss the conformational behavior of single-chain sequence-defined polyampholytes modeling intrinsically disordered proteins (IDPs). For polyampholytes/IDPs with a non-zero net charge, the interplay between sequence-dependent correlation-induced attractions and bare Coulomb repulsions results in different conformations ranging from spherical globules to strongly stretched chains, including “necklaces” of various structures containing several smaller globules connected by the extended strings.
January 28, 2022
10:30 AM
EB2 Room 1021
Dr. Wentao Tang
Shell Global Solutions (U.S.) Inc.
Optimally controlling large-scale interconnected chemical plants, or process networks, is a bottleneck problem in the theory and practice of contemporary process control. This demands a structured and scalable approach with effective methods of decomposing process networks into constituent subsystems and coordinating the controllers for subsystems. With the perspective of network science, community detection is proposed to reveal the underlying block structures in the network representations of control systems, which generates decompositions with reduced computational cost and retained control performance. For subsystem controller coordination, distributed optimization is adopted to guarantee the optimal solution for the monolithic system, and efficient and real-time implementable algorithms are developed to overcome the computational challenge of applying distributed optimization in control. The methods are applied to multiple benchmark processes, and future directions are discussed.
January 31, 2022
10:30 AM
EB1 Room 1011
Dr. Mitchell Wang
Northwestern University
The Wang Lab develops new methods for characterizing polymers to address today’s challenges, with the philosophy that new methods for seeing and measuring often open completely new fields of application and fundamental study. As an example, we use single-molecule super-resolution microscopy to image samples in their native environments and watch them as they evolve. We have applied this to fundamental questions in polymer self-assembly, mechanics, and dynamics, enabling engineers to control where and when something happens in a polymeric material. For example, we have recently answered the question of what a polymer looks like in a solid material, for the first time. Separately, we are developing high-throughput characterization methods for mechanical properties in soft materials. These techniques can change the way materials are designed in the era of AI and machine learning.BIOMuzhou “Mitchell” Wang received his undergraduate degree in Chemical Engineering from Caltech, where he worked with Prof. Julia A. Kornfield. He then went to MIT for his Ph.D. studies, joining Prof. Bradley D. Olsen as his first student. In the Olsen group, he used experiments and simulations to understand the dynamics of entangled block copolymers. He continued his work as a National Research Council postdoctoral fellow at the National Institute of Standards and Technology, where he worked on super-resolution optical microscopy of nanofabricated polymer materials with Dr. Jeffrey W. Gilman and Dr. J. Alexander Liddle. He started his group at Northwestern in 2017, where he has been recognized with a number of honors including an NSF CAREER award and an APS DPOLY/UKPPG Lectureship.
February 7, 2022
10:30 AM
EB2 Room 1021
Dr. David Koshy
Fritz Haber Institute of the Max Planck Society
Electrochemical CO2 reduction (CO2R) has attracted significant interest as a route for producing carbon-based fuels and chemicals using renewable electricity and operating at ambient conditions. Due to the challenging kinetics of CO2R, electrocatalysts are needed to achieve reasonable rates for products like carbon monoxide (CO), ethanol, or ethylene.Ni, N-doped carbon (Ni-N-C), a material consisting of nitrogen and nickel dopants in a graphitic carbon matrix, has recently been reported as an active and selective catalyst for CO2 reduction to CO. Ni-N-C catalysts are hypothesized to be “single atom catalysts” which contain atomically dispersed, nitrogen-coordinated NiNx sites that are structurally similar to molecular Ni complexes. However, the search for evidence to support this this active site hypothesis has not yielded proof that these NiNx sites exist or that they are CO2R active sites.This talk describes the use of a wide variety of complementary characterization techniques to obtain a holistic understanding of the CO2R active site on Ni-N-C materials. Specifically, kinetic measurements were combined with physiochemical characterization techniques including electron microscopy, X-ray photoelectron spectroscopy, X-ray absorption spectroscopy, mass spectrometry, electron energy loss spectroscopy, and Mössbauer spectroscopy. This multimodal approach revealed that NiNx sites are likely CO2R active sites and that Ni2+ is present in a distorted square-planar geometry with nitrogen coordinating atoms.Next, the thermal stability of these Ni-N-C materials provided a unique opportunity to directly compare the conversion of CO2 to CO under an electrochemical driving force (CO2 reduction) and a thermochemical driving force (reverse water gas shift, RWGS). This comparison showed that the same Ni-N-C powder could catalyze both electrochemical CO2R and thermal RWGS, demonstrating a direct connection between catalytic activity across disparate reaction environments. To strengthen this comparison, the driving forces for the two reaction systems were quantitatively compared. This analysis revealed that the higher intrinsic activity of Ni-N-C in the electrochemical environment likely originates from lowered reaction barriers at the electrified interface.In summary, this research demonstrates that Ni-N-C materials exhibit unique catalytic activity that intersects many subdisciplines of catalysis science: containing molecular-like active sites in a heterogeneous framework and catalyzing analogous chemical transformations in both electrochemical and thermal reaction conditions.
February 9, 2022
10:30 AM
EB1 Room 1011
Dr. Christopher J. Bartel
University of California, Berkeley
Countless technologies are enabled by the development of improved solid-state materials (e.g., layered oxides for Li-ion battery cathodes, nitride semiconductors for light-emitting diodes, and hybrid perovskites for photovoltaics). The transition to an energy portfolio free of fossil fuels demands that the materials used for these technologies become cheaper, more efficient, and more sustainably sourced. Quantum chemistry has emerged as a useful tool to computationally prototype new candidate materials before they are tried in the lab. However, the efficient identification of good candidates is made daunting by the broad diversity of chemistries and structures that can be realized in the solid state. This vast design space has motivated the emergence of materials informatics, where computational chemistry and machine learning meet to accelerate the discovery of new materials with emergent properties. No matter the application of interest, materials discovery efforts hinge upon on an essential question — is this candidate material stable? In this talk, I will discuss how I address this question using simple and interpretable models called descriptors. Finally, I will show how we can move beyond the question of stability and toward a new paradigm of predictive materials synthesis.
February 11, 2022
10:30 AM
EB2 Room 1021
Dr. Robert Warburton
Yale University
In the transition away from fossil fuels, high-performance electrochemical devices are needed to realize new routes to transportation, energy storage, and chemical synthesis solutions. Understanding the electrochemical redox reactions at the electrode–electrolyte interface in such systems is therefore essential toward the rational optimization of electrochemical devices for energy-critical applications. First principles theoretical calculations, such as density functional theory (DFT), can be a useful approach to elucidate the atomic-scale structure and reactivity of interfaces in electrochemical systems. In this talk, I will describe the application of such computational methods to the analysis of interfacial thermodynamics, as well as the impact of interfacial electric fields on desolvation and electrocatalytic reactivity. These phenomena will be explored using atomistic models, with specific examples applied to solid-state lithium-ion batteries, vibrational probes of local electric fields at electrode–solution interfaces, and proton-coupled electron transfer reactions at graphite-conjugated molecular catalysts. In combination with accompanying experimental measurements, these studies shed new light on critical interfacial processes in electrochemical systems.

February 14, 2022
10:30 AM
EB1 Room 1011
Dr. Julie Rorrer
Massachusetts Institute of  Technology
The rapid global consumption of single-use plastics has caused an unsustainable accumulation of plastic waste in landfills and the environment. Unfortunately, current mechanical recycling methods are expensive and produce lower-quality products. New strategies in targeted chemical upcycling of waste plastics offer unique opportunities for selective depolymerization of polyolefins to higher value chemicals under milder conditions than thermal deconstruction or pyrolysis. Inspired by recent developments in the depolymerization of lignin, we turned to the method of hydrogenolysis to break the strong C-C bonds in polyolefins. This talk will cover our efforts in identifying a class of ruthenium-based materials as active and selective heterogeneous catalysts for the depolymerization of polyolefin waste, catalyst support modification strategies to further improve selectivity towards processible liquid alkanes, and new frameworks for the chemical upcycling of waste plastics and complex mixed waste streams to enable a circular carbon economy.
February 16, 2022
10:30 AM
EB1 Room 1011
Dr. Ivan A. Moreno-Hernandez
University of California, Berkeley
Electrochemical materials are required to store renewable energy and sustainably couple the chemical and energy industries. This talk will focus on advancements in both the discovery of new electrochemical materials with improved performance and the development of new techniques to observe the structural dynamics of electrochemical materials. We will first discuss the discovery of an earth-abundant class of electrocatalysts that are thermodynamically stable for the oxygen evolution and chlorine evolution reactions in acidic electrolytes. Our discussion will then focus on the development of a redox-mediated approach to control electrochemical reactions in liquid cell electron microscopy, a technique that allows reactions to be observed at near-atomic resolution over time.
February 21, 2022
10:30 AM
EB1 Room 1011
Dr. Sheima Khatib
Texas Tech University 
Methane, derived from shale gas, is a cheap and abundant molecule that can be used as a building block in the chemicals manufacturing industry, but instead, large quantities of stranded shale gas are being flared due to lack of existing infrastructures for its transportation to centralized processing facilities. The catalytic valorization of methane to aromatics and hydrogen, by the one-step non-oxidative methane dehydroaromatization reaction (6 CH4  C6H6+ 9H2), MDA, is an attractive route for natural gas upgrade since it can be implemented at the gas source, offering the opportunity for development of modular technology for distributed manufacturing of aromatics while reducing processing and transportation costs. Our group is carrying out a systematic study of this catalytic process with the aim of answering long-standing fundamental questions related to MDA chemistry which will enable development of strategies to mitigate the technological challenges associated with MDA.
Zeolite-supported molybdenum catalysts are the most effective MDA catalysts studied so far, but they do not possess conversion and stability requirements for commercialization. Molybdenum carbide species are thought to constitute the active sites for MDA and are formed when the zeolite-supported Mo oxide species in the as-prepared catalysts are exposed to methane in the first minutes of reaction. In this talk I will describe how our group has discovered that the activation protocol employed to form the active molybdenum carbide sites plays a critical role in catalyst stability. I will also present how our studies on the effect of the zeolite acidity employing in situ/operando X-ray absorption spectroscopy suggest that the structure of local environment of the as-prepared molybdenum oxide sites does not affect the catalyst performance, underpinning the importance of controlling the carbide formation step. I will also discuss our most recent results indicating that the addition of small amounts of a second transition metal promoter, such as cobalt and nickel, employing our new activation protocol results in further enhancement of catalyst stability.
February 23, 2022
10:30 AM
EB1 Room 1011
Dr. Dohyung Kim
Stanford University  
There has been growing interest to drive chemical reactions via the direct use of renewable electricity to address sustainability challenges. The success of the approach rests on the use of the right materials to efficiently catalyze electrochemical reactions. Thus, there have been intense efforts to engineer catalyst materials whose surface contains the desired active sites. Despite the success, there is still much room for improvement in the field of electrocatalysis. However, it is not because of our limited advances in the synthesis of materials and their use as catalysts. It is because of how we typically view catalytic reactions at the solid-liquid interface that often lacks consideration of the liquid phase (e.g., solvent molecules, double-layer ions). The “BEYOND SURFACE” approach that not only recognizes the presence and role of liquid phase components but alters their characteristics to facilitate chemical reactions will bring the necessary advances to progress beyond the performance levels achieved to date. In this talk, two examples of the “BEYOND SURFACE” approach are presented for electrocatalytic reactions of renewable carbons, CO2 and biomass. The first example concerns the discovery of a unique interfacial configuration on the surface of colloidal nanoparticles, that is the Nanoparticle/Ordered-Ligand Interlayer (NOLI). Its operation as a catalytic pocket for CO2 reduction by the synergistic act of the nanoparticle surface and surface ligands hovering above suggests a new route to promote reactions by tuning the electric double layer using materials. The other example presents the need for a better understanding of solvent molecule behavior at electrochemically active interfaces. During electrooxidation of biomass-derived polyols, it is shown that the interaction between the Pt surface and surrounding water eventually leads to its surface oxidation limiting catalytic activity at fixed potential conditions. Thus, a unique method so-called electrochemical potential cycling is devised that continuously cycles between oxidative and reductive potentials exploiting the short-lived high activity state of Pt nanoparticles otherwise difficult to maintain under typical conditions. These studies highlight the complexity of electrochemical interfaces and the potential of thinking beyond the surface for electrocatalytic reactions.
February 28, 2022
10:30 AM
EB1 Room 1011
Dr. Fang Liu
Stanford University
High-energy density batteries will play a remarkable role in hurdling global climate change. My research focuses on the fundamental understandings of their electrochemical reaction mechanisms and the design of materials, protocols, and characterization tools to enable their safe operations over long-term use. First, I will discuss about the previously overlooked dynamics of detached lithium metal filaments during battery operations. This discovery leads to the recovery of lost capacities in lithium-metal batteries and enables fast charging in lithium-ion batteries. Next, I will introduce a characterization tool for the on-board monitoring of battery health based on pressure evolutions. In addition to capturing the early signs of battery failure, this pressure sensing system offers new insights into the battery degradation process. Overall, the combination of fundamental study and the rational design of materials/protocols/characterization tools opens broad opportunities toward a clean energy future.
March 7, 2022
10:30 AM
EB1 Room 1011
Dr. Lynden Archer
Cornell University
McCabe Lecture
The levelized cost of electric power generated from renewable resources have fallen continuously over the last decade. This trend is rightly fueling optimism about humanity’s ability to achieve net-zero carbon emissions in the electric power generation and transportation sectors—without the large government subsides predicted as recently as a decade ago. It is known that the intermittency and seasonal variability of the electric power supply from wind and solar sources pose significant barriers to broad-based acceptance of clean electric power. Low-cost options for storing large quantities of renewable electric power would lower/eliminate these barriers and meet an unmet need in both the power generation and transportation sectors. Rechargeable electrochemical cells (a.k.a. batteries) based on metallic anodes, including lithium, zinc, and aluminum, offer the potential for transformative advances in cost-effective storage of electrical energy. Research over the last decade has shown that recharge of any metal anode requires reversible nucleation and growth of crystalline structures with symmetries that are rarely, if ever, consistent with those dictated by the fields inside a closed battery cell. This means that the interfacial products from spontaneous electrode growth reactions in a battery cell are in most cases fundamentally incompatible with requirements for achiving the very high levels of reversibility required for practical relevance. This talk addresses this problem by first considering the fundamental stability limits for metal electrodeposition processes in liquid and semisolid structured electrolytes from multiple perspectives. The analysis leads to testable design concepts for enabling metal anodes with high levels of reversibility.
March 21, 2022
10:30 AM
EB1 Room 1011
Dr. Heath Turner
University of Alabama
Traditional atomistic-level quantum mechanical or molecular dynamics (MD) simulation approaches are often unable to capture the correlated events that occur during the structural/chemical evolution of nanostructured materials, due to the time scales involved.  To deal with these challenges, we have developed kinetic Monte Carlo (KMC) modeling approaches for capturing the relevant kinetics and equilibrium properties, including automated techniques for cycling between KMC and MD stages.  Three different applications will be highlighted: (a) growth of Au nanoparticles in solution; (b) gas separation performance of ionic polyimide membranes; and (c) growth of amorphous tribofilms on metal surfaces.
March 28, 2022
10:30 AM
EB1 Room 1011
Dr. Levi  Thompson
University of Delaware
The insertion of carbon and nitrogen into the interstitial sites in Mo and V can transform these metals into materials with properties that resemble those of noble metals like Au and Pt. This talk will describe our understanding of how key reactants like hydrogen interact with these materials as well as their catalytic properties. Interestingly hydrogen in the subsurface can influence the surface catalytic reactions of some nitrides. Because carbides and nitrides can be produced with high surface areas, they are also used to support other catalytic species. The resulting materials can be highly active and selective for cascade reactions of importance for biomass conversion.
April 4, 2022
10:30 AM
EB1 Room 1011
Dr. George Jackson
Imperial College London
Gubbins Lecture
The physical description of small fluid drops covers two centuries from the first mechanical treatment of Young and Laplace, through the formal thermodynamics of Gibbs and Tolman, to modern statistical mechanics following on from the work of Kirkwood and Buff. In spite of this, there is still controversy with respect to the effect that curvature has on surface properties. Gubbins and co-workers undertook the earliest comprehensive study of the vapour−liquid surface tension of drops obtained by molecular dynamics (MD) simulation from both mechanical (pressure-tensor) and thermodynamic (Tolman and Laplace) routes, recognizing the inadequacy of the Laplace and Kelvin relations for small drops. Gubbins and co-workers were also the first to employ classical density functional theory (DFT) to study drops with a mean-field perturbation theory in the canonical ensemble (whip enable one to study ‘stable’ equilibrium drops), evaluating the surface tension using a combination of the Laplace and Tolman relations. The test-area (TA) perturbation approach has been gaining popularity as a methodology for the direct computation of the interfacial tension in molecular simulation. Though the Kirkwood-Buff (mechanical) and TA (thermodynamic) approaches provide an equivalent description of the interfacial tension of the planar vapour-liquid interface, stark differences are found in the case of spherical drops: important entropic contributions are found to be missing from a standard mechanical treatment. An interpretation of the TA method is provided taking the view that it corresponds to the change in free energy under a transformation of the spatial metric. We undertake a geometric analysis of the TA method and employ the technique to determine the vapour-liquid interfacial tension of Lennard-Jones particles and TIP4P/2005 water for planar, cylindrical, and spherical geometries. By expressing the change in configurational energy of a molecular configuration as a Taylor expansion in the distortion parameter, compact relations are derived for the interfacial tension and its energetic and entropic components for the three different geometries. A weak peak in the curvature dependence of the tension is observed in the case of cylindrical threads of condensed TIP4P/2005 liquid at a radius of about 8 Å, below which the tension is found to decrease again. In the case of spherical drops a marked decrease in the tension from the planar limit is found for radii below 15 Å. The vapour-liquid interfacial tension tends towards the planar limit for large system sizes for both the cylindrical and spherical cases. Time permitting, we will also discuss the use of test-volume (TV) deformations of non-spherical rod-like particles to determine the pressure of the system which is characterised by apparent asymmetry of the compressive and expansive tensorial contributions. The appropriate description of the pressure tensor allows for a reliable determination of the fluid−solid surface tension for systems of anisotropic particles in contact with solid substrates.
April 5, 2022
3:00 PM
EB1 Room 1011
Dr. George Jackson
Imperial College London
Gubbins Lecture
The application of the “top-down” SAFT- concept for the development of accurate coarse-grained force fields for the molecular simulation of complex fluids is presented. With the more common employed “bottom-up” procedure, coarse-grained models are constructed from a suitable simplification of a fully detailed atomistic representation, and minor (iterative) refinements to the intermolecular parameters are made by comparison with limited experimental where necessary. By contrast, in a top-down approach, a molecular-based equation of state can be used to obtain an effective coarse-grained intermolecular potential that reproduces the macroscopic experimental thermophysical properties over a wide range of conditions. The most successful modern equation of states invariably stem from the early work of Gubbins and co-workers on the development of an accurate thermodynamic perturbation theory for associating chain molecules, embodied in the statistical associating fluid theory (SAFT) and its many varients. Here, we describe a top-down coarse-graining methodology using the SAFT- group-contribution approach, which itself is based on the hetero-group implementation of statistical associating fluid theory of variable range (SAFT-VR) employing a Mie (generalised Lennard-Jones) potential. The interactions between the representative coarse-grained chemical groups can be determined reliably with such an approach from readily available target experimental properties such as the vapour pressure, saturated-liquid density, and/or mixture fluid-phase coexistence data. In order to demonstrate the versatility and reliability of the SAFT- coarse-graining methodology, we present representative examples of its application in the development of force fields for systems of varying chemisty including carbon dioxide, light green-house gases and refrigerants, n-alkanes, water and aqueous mixtures, polystyrene polymers, and amphiphilic systems comprising surfactants. Molecular dynamics simulations with the SAFT-γ models are found to provide an accurate description of the fluid-phase behaviour and predictions of properties which were not used to develop the force field such as the enthalpy of vaporisation, interfacial tension, density profiles, supercritical densities and second-derivative thermodynamic properties, as well as structural proprieties including correlation functions and microstructure. The reliable simultaneous predictions of transport properties such as the diffusion coefficient and viscosity which are not accessible from a thermodynamic description is particularly pleasing. The accuracy of SAFT-γ coarse-grained force fields are found to be of similar quality to that of more sophisticated all-atom or united atom intermolecular potentials at a fraction of the computational cost of the more detailed models. Time permitting, we will also briefly discuss an extension of the course-graining approach for the development of fluid-surface potentials for molecules interacting with homogeneous and heterogeneous solid substrates; in this case a bottom-up methodology based on detailed all atom or united-atom force is described
April 11, 2022
10:30 AM
EB1 Room 1011
Dr. John Brady
California Institute of  Technology
A distinguishing feature of many living systems is their ability to move – to be active. Through their motion living systems are able self-assemble: birds flock, fish school, bacteria swarm, etc. But such behavior is not limited to living systems. Recent advances in colloid chemistry have led to the development of synthetic, nonliving particles that are able to undergo autonomous motion by converting chemical energy into mechanical motion and work. This intrinsic activity imparts new behaviors to active matter that distinguish it from equilibrium systems. Active matter generates its own internal stress, which can drive it far from equilibrium, and by so doing active matter can control and direct its own behavior and that of its surroundings. In this talk I will discuss our recent work on active matter and on a new source of stress that is responsible for self-assembly and pattern formation in active matter systems.
April 18, 2022
10:30 AM
EB1 Room 1011
Dr. Jackie Bruce
NC State University
It’s a universal truth that working with people can be messy and confusing. This session will provide participants with evidence based strategies allowing them to navigate those difficult times and help elevate their leadership practice.
Jackie Bruce is a leadership educator and faculty member in the Department of Agricultural & Human Sciences. At NC State, Jackie teaches courses in leadership development and qualitative research methods and advises undergraduate and graduate students. She serves as the Co-Director of the Oaks Leadership Scholars Program, is an Equal Opportunity Institute Graduate Scholar and an LGBT Center advocate.
April 25, 2022
10:30 AM
EB1 Room 1011
G.V. Reklaitis
Purdue University
Ollis Lecture
Innovative technologies offer the potential to modernize pharmaceutical manufacture, improving quality and reliability and reducing cost but the innovations have been be slow in realization. The Covid pandemic has shown how important innovations in pharmaceutical products and in manufacturing processes are in addressing this global healthcare emergency. Indeed, manufacturing issues have arisen with several of the alternative vaccine products delaying their availability to patients. Moreover, the normal regulatory process also had to be expedited via emergency authorizations reflecting the barriers to new technologies that the existing process creates. The differences in timing of approvals in different geographic regions given the same clinical data pointed to a need for harmonization of these regulatory processes.Recognizing that these issues need to be better understood and addressed, the FDA in late 2019 commissioned the US National Academies of Science, Engineering and Medicine (NASEM) to undertake a study to identify the emerging technologies, the technical challenges to their translation to practice, and the regulatory challenges that might exist in implementing them as well as to provide recommendations to overcome the regulatory challenges. In the technology area, the findings include the identification of emerging technologies with the potential to advance pharmaceutical quality and modernize manufacturing of FDA Center for Drug Evaluation and Research (CDER) regulated products. The technologies identified could be classified into four areas: drug substance, drug product, automation and control technologies, as well as innovative manufacturing networks. In the regulatory domain the challenges identified include those in the review process itself, the lack of alignment of incentives for innovation, the impediments arising due to differences in the regulatory process in different regions and countries, the handling of post-approval changes and internal limitations within the FDA itself. The study report which offered targeted recommendation was released in Spring 2021 [1]. A follow-on workshop, again sponsored by the Center for Drug Evaluation and Research (CDER), was convened by NASEM on October 29-29, 2021 [2]. The follow-on workshop served to update the findings of the original study in the light of the impact that Covid has had on the industry, to discuss and provide feedback on the recommendations, both from industry and FDA, and to provide a forum for the FDA to outline initiatives taken in response. The proceedings of this workshop will be released by NASEM in the coming months. In this presentation we will summarize the key findings and recommendation of the 2021 report as well as those of the follow-on workshop and discuss some outcomes that have already been realized.1. https://www.nap.edu/catalog/26009/innovations-in-pharmaceutical-manufacturing-on-the-horizon-technical-challenges-regulatory2. https://www.nationalacademies.org/event/10-28-2021/innovations-in-pharmaceutical-manufacturing-on-the-horizon-a-virtual-dissemination-workshop
May 3, 2022
9:00 AM
EB1 Room 2018
Yiliang Lin
National University of Singapore
Interfacial molecular interactions are at the heart of all biological processes. Ideal bio-interfaces would facilitate signal transductions by providing optimized biomaterial-cell interactions. With the increased capability to manipulate matter at different length scales, new bio-interface materials are being developed through different material selections and designs. Today, my talk will first introduce our efforts on the development of functional soft materials for bio-interfaces. I will showcase a few examples of unconventional, room-temperature patterning techniques with liquid metals and their applications in soft electronics and biomedical applications. Next, I will discuss several strategies for integrating semiconductors with living bacteria for biohybrid systems. The systems enable the discovery of transient signal transduction within the microbial community and the coupling of photo-responsive materials with living bacteria for microbial modulation. I will specifically highlight a material synthetic biology approach to yield microbial nanowires and semiconductor nanoparticles, where the nanoparticles can couple the optical modulation with bacterial energy metabolism. Lastly, I will highlight my recent research on soil-inspired chemical systems, where multiscale soft-hard material integration has yielded a responsive matrix. In addition to enhancing the microbial growth in vitro, the responsive matrix can modulate the gut microbiome in vivo for disease therapy. These rational bio-interface studies will help develop multiscale living materials to meet emerging needs, from the human-machine interface in telemedicine, biomedical therapy to sustainable agriculture.
May 6, 2022
2:30 PM
EB1 Room 1007
Greg McKenna
NC State University
There are several schools of thought related to complex fluid behavior that are based on the existence of an ideal, thermodynamic glass transition at which temperature the dynamics of the system diverge, i.e., the viscosity or relaxation times become infinite at a finite temperature above absolute zero. This temperature is thought to be related to the Kauzmann [3] temperature TK where the configurational entropy extrapolates to zero. But it remains a major challenge in glass physics to determine the temperature dependence of the relaxation times in the equilibrium state well below the laboratory glass temperature Tg and approaching to this TK value. The challenge arises because the times required to achieve equilibrium in this regime become of geological/ astronomical scale [2,3]. Yet, modeling of real glass behavior requires a knowledge of the equilibrium response. Thus, it becomes important to find away to finesse the timescale problem. To this effect, we have developed novel materials with extremely
low fictive temperatures Tf relative to Tg, hence unlocking an unexplored region of the glassy state to investigation. First, we measured the viscoelastic response of a 20 million year old amber with Tf ∼ 43.6 K below Tg, i.e., approximately 63% towards the “bottom” of the energy landscape at TK. Using time temperature superposition methods we have been able to show that the relaxation times deviate strongly from the expected finite temperature divergent behaviors and turn towards an Arrhenius response, albeit with a high activation energy. Though convincing as evidence that the dynamics of the glass do not diverge at a finite temperature, the amber work is complicated because the natural origins of amber have made expansion beyond these results to lower fictive temperatures difficult. To further expand the work to greater depths in the energy landscape, we have built on the ideas of ultra-stable glasses made by vapor deposition exploited by Ediger and co-workers for small molecules [4] and made an amorphous Teflon [5] material with Tf ∼55 K below Tg and close to the putative TK (the ideal glass temperature of 346 K) hence, some 93% of the way to the bottom of the energy landscape. Made only in microgram quantities, we used a nano-bubble inflation [6] method to measure the creep dynamics of the amorphous Teflon in the range between Tf and Tg, expanding the amber work to very near TK. The observed relaxation times deviate from the extrapolated VFT- (finite temperature divergence) line, thus challenging the view that there is an “ideal” glass transition. The data for both the amber and the ultra-stable amorphous Teflon will be compared to predictions of the temperature dependent dynamics from both entropy theories and elasticity theories of the glass transition. Ongoing work is also described.