IBM Research - Almaden Science Colloquium Series - IBM Research Almaden ARC ANGELS Student Seminar Series
Science and Technology welcomes researchers from academia and industry to present their work in Almaden's Science Colloquium Series.
Science and Technology staff who are interested in inviting researchers for this series are encouraged to contact Gavin Jones (firstname.lastname@example.org) or Greg Wallraff (email@example.com) to arrange presentations.
Topic: Inside Out: Visualizing Chemical Transformations and Light-matter Interactions with Nanometer-scale Resolution
Speaker: Prof. Jennifer Dionne (Stanford University)
Date: 1/26/2017 Time: 10:30 AM - 11:30 AM
Abstract: In Pixar’s Inside Out, Joy proclaims, “Do you ever look at someone and wonder, what’s going on inside?” My group asks the same question about materials whose function plays a critical role in energy and biologically-relevant processes. This presentation will describe new techniques that enable in situ visualization of chemical transformations and light-matter interactions with nanometer-scale resolution. We focus in particular on i) ion-induced phase transitions; ii) optical forces on enantiomers; and iii) nanomechanical forces using unique electron, atomic, and optical microscopies. First, we explore nanomaterial phase transitions induced by solute intercalation, to understand and improve materials for energy and information storage applications. As a model system, we investigate hydrogen intercalation in palladium nanocrystals. Using environmental electron microscopy and spectroscopy, we monitor this reaction with sub-2-nm spatial resolution and millisecond time resolution. Particles of different sizes, shapes, and crystallinities exhibit distinct thermodynamic and kinetic properties, highlighting several important design principles for next-generation storage devices. Then, we investigate optical tweezers that enable selective optical trapping of nanoscale enantiomers, with the ultimate goal of improving pharmaceutical and agrochemical efficacy. These tweezers are based on plasmonic apertures that, when illuminated with circularly polarized light, result in distinct forces on enantiomers. In particular, one enantiomer is repelled from the tweezer while the other is attracted. Using atomic force microcopy, we map such chiral optical forces with pico-Newton force sensitivity and 2 nm lateral spatial resolution, showing distinct force distributions in all three dimensions for each enantiomer. Finally, we present new nanomaterials for efficient and force-sensitive upconversion. These optical force probes exhibit reversible changes in their emitted color with applied nano- to micro-Newton forces. We show how these nanoparticles provide a platform for understanding intra-cellular mechanical signaling in vivo, using C. elegans as a model organism.
Topic: Not Big Enough for the Both of Us: Proximal Effects in Catalysis and Materials
Speaker: Prof. Madalyn Radlauer (San Jose State University)
Date: 6/8/2018 Time: 10:30 AM - 11:30 AM
Abstract: Proximity and sterics play a large role in catalysis and polymer chemistry. In the development and testing of bimetallic polymerization catalysts where the two metal centers are held on the same side of the molecule by a rigid ligand framework, the proximity of the second metal changes reactivity at the first. The resulting enhancements of polar group tolerance or isoselectivity in olefin polymerization are not observed in related bimetallic systems with distal metal centers or in monometallic analogues. In multiblock polymers, the proximity of incompatible blocks due to a covalent connection engenders frustration in the system. This frustration can produce interesting and complicated morphologies in the bulk and in thin films where thermodynamic penalties are expected to minimize the inter-material dividing surface. Our current work aims to harness the power of proximity in directing reactivity, selectivity, and equilibria to enhance catalysis by embedding catalysts within polymeric frameworks. We are targeting transition metal catalysts appended to synthetic organic polymers to study the effects of the macromolecular environment on catalytic reactions applicable to organic synthesis and fuel production.
Topic: Bridging Gaps Between Computational and Experimental Aspects of the Fourth Paradigm
Speaker: Dmitry Zubarev, Ph. D. (IBM Research - Almaden)
Date: 6/15/2018 Time: 10:30 AM - 11:30 AM
Abstract: A characteristic feature of the Fourth Paradigm is abstraction of the experiment from the design of experiments, where the latter is treated as a problem in the domain of data-driven computational chemistry. This abstraction creates unique challenges for the efficient propagation of the computational findings into the experimental phase. In this talk I will discuss two research directions in IBM Research Accelerated Material Discovery program that aim to make computational findings more actionable. The first direction is incorporation of chemical ontologies into the computational discovery workflow that enables engagement of the subject matter experts who don't have relevant computational background. The second direction is construction and comparison of representative sets in classification problems where experimental phase has severe throughput limitations.
Topic: Structure-property Relationships of (Co)polyester Regioisomers: From Polymers for Packaging to Understanding Cyclic Formation
Speaker: Ryan Mondschein (Virgina Tech)
Date: 6/22/2018 Time: 10:30 AM - 11:30 AM
Abstract: Identifying novel polymers which combine high barrier performance with thermal stability and mechanical properties is crucial for a polymer platform to compete with current industrial thermoplastics. Unique bibenzoate monomers enabled the synthesis of polyester regioisomers containing linear and kinked repeat units. Tuning monomer ratios afforded polyesters with thermal and mechanical properties near or surpassing polycarbonate, while also improving barrier performance compared to PET. Melt rheology studied flow behavior, and TTS revealed distinct flow relaxations providing insight into fractional free volume, flow activation energies, and entanglement. Advanced permeation chromatography confirmed high molecular weight, while elucidating multiple low molecular weight peaks, presumably cyclics. Step-growth polymerizations produce cyclics in equilibrium with linear polymer chains. Structural alterations, such as regiochemistry, influences the quantity, molecular weight, and dispersity of cyclics. Small molecule cyclics impact in polymers ranges from complications in processing to influencing barrier performance. Thus, understanding the influence of monomer regiochemistry on cyclic formation allows for predicting cyclic quantity and size. Characterization utilizing analytical techniques of extracted cyclics resulted in the size and shape of the cyclics, while controlling cyclic weight percent incorporation can impact rheological, mechanical, and barrier properties. Through systematic studies to quantify and predict cyclic formation, the development of structure-property relationships enables key understandings of cyclics influence on polymer properties.