Plenary Talks

Energy Conversion and Storage: Novel Materials and Operando Methods, Héctor D. Abruña, Department of Chemistry & Chemical Biology and Center for Alkaline Based Energy Solutions(CABES), Cornell University, Ithaca, NY.
Abstract: This presentation will deal with the development of new materials and operando methods for energy conversion and storage with emphasis on fuel cells and battery materials and technologies. The presentation will begin with a brief overview of the methods employed with emphasis on the use of X-ray based methods and transmission electron microscopy (TEM) under active potential control. The utility of these methods will be illustrated by selected examples focusing on non-precious metal electrocatalysts for the oxygen reduction reaction (ORR), and MEA testing as well as spectroscopic studies of Li/S batteries, Li metal deposition and the use of organic materials in electrical energy storage applications. The presentation will conclude with an assessment of future directions.
CHESS and PREM CIE2M, Joel D. Brock, Cornell High Energy Synchrotron Source (CHESS) and Engineering School of Applied & Engineering Physics, Cornell University, Ithaca, NY.
Abstract: The goal of DMR’s PREM program is to “… enable, build, and grow partnerships between minority-serving institutions and DMR-supported centers and/or facilities ….”1 Historically, PREMs were exclusively partnerships with research centers. CIE2M is the first PREM with a national user facility as the partner and the novel partnership is a huge success. In addition to meeting the goals of training students in x-ray data collection and analysis and supporting the synchrotron-based research programs of the PREM faculty, CIE2M’s unique partnership has enabled students to participate in the commissioning of new x-ray facilities at CHESS. This com-bination of experiences has generated prize-winning research, motivated undergraduates to pursue graduate study utilizing synchrotron-based x-ray techniques, and generated additional, high-profile successful collaborations, most notably, the Mid-Scale Research Infrastructure project to build a High Magnetic Field (HMF) facility at CHESS. Graduate students from UPR are an integral component of the HMF collaboration (with CHESS and the NHMFL) and are already developing experimental programs and helping to design new systems for studying materials in high magnetic fields with x-rays. On graduation, these HMF graduate students will become international leaders in this new research area.
Particle-stabilized multiphasic mixtures for energy, healthcare and sensing applications, Daeyeon Lee, Department of Chemical and Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA.
Abstract: Mixing two immiscible fluids (oil/water or air/water) in the presence of particles lead to strong adsorption of particles to the interface and formation of particle-stabilized multiphasic mixtures such as Pickering emulsions and liquid marbles. Because of their high stability, these particles-stabilized multiphasic mixtures can be used for a variety of applications including encapsulation and release of active agents as well as sensing and conversion of molecules. In this presentation, I will describe a new class of multiphasic mixtures called bijels (bicontinuous interfacially jammed emulsion gels) which present a unique morphology of intertwining network of two immiscible fluids stabilized by interfacially jammed particles. Several strategies to form bijels including thermal quenching of homogenous binary mixtures and shearing phase-separated biphasic mixtures in the presence of neutrally wetting particles have been introduced. As a complementary method, we explore the formation of bijels from a homogenous ternary mixture of water, oil and co-solvent. Phase separation is triggered by inducing the removal of the co-solvent via extraction or evaporation. The use of silica nanoparticles and ionic surfactants enables continuous and scalable manufacturing bijels with controllable morphologies and domain sizes down to a few hundreds of nanometers. This presentation will describe the effect of solvent removal process (extraction vs. vaporization) on the morphology and microscale structure of bijels. Surfactant-free bijels stabilized by mixtures of hydrophobic and hydrophilic nanoparticles can be produced; the ratio of these two particles must be changed depending on the polarity of the oil phase, enabling the fabrication of bijels with a wide range of oils of varying polarity. Taking advantage of the versatility of using ternary mixtures, we are exploring application of bijels for reactive separations, energy storage and passive daytime radiative cooling.
Building Bioactivity into ‘Slippery’ Liquid-Infused Porous Surfaces, David M. Lynn, Department of Chemical and Biological Engineering and Department of Chemistry, University of Wisconsin—Madison, Madison, WI.
Abstract: Slippery liquid-infused porous surfaces (or ‘SLIPS’) provide new approaches to prevent biofouling on commercial and industrial surfaces, including those used to design medical devices. Many different types of SLIPS have been demonstrated to resist fouling and colonization by microorganisms. However, while SLIPS are generally good at preventing fouling on surfaces to which they are applied, they can generally do little to prevent proliferation of non-adherent organisms—e.g., to stop them from colonizing other surfaces or prevent them from engaging in other behaviors, such as virulence factor production, that can also lead to infection or fouling. We have developed multi-functional and bioactive SLIPS that address these issues and expand the potential utility of liquid-infused surfaces in antimicrobial contexts. Our approach is based on incorporation and controlled release of antimicrobial agents from hydrophobic porous polymer matrices used to host infused lubricant. This approach can prevent short- and longer-term colonization and biofilm formation by common fungal and bacterial pathogens. This approach improves the inherent anti-fouling properties of these materials, enables them to efficiently kill planktonic pathogens, and can endow them with other useful functional properties. Both the polymer and liquid phases comprising these materials can be exploited to load and sustain the release of active agents; recent efforts to design antifouling surfaces infused with water-in-oil nanoemulsions (‘SNIPS’) that can release water-soluble agents will also be discussed. This approach is modular in nature and can be used to fabricate multi-functional, bioactive SLIPS on complex surfaces, including the luminal spaces of flexible polymer tubing used to fabricate catheters. We anticipate that these strategies and concepts will also open the door to completely new applications of slippery liquid-infused materials. Efforts to design SLIPS using biodegradable and biocompatible building blocks will also be discussed.
Perovskites: what's the big deal...and how can I get involved?, Andrew Rappe, Department of Chemistry, University of Pennsylvania, Philadelphia, PA.
Abstract: The perovskite crystal structure holds a special place in scientific research, serving both as perennial workhorse for decades and platform for a variety of hot topics. In this lecture, I will begin by making the case that this place is deserved, by introducing the perovskite structure and some of the interesting phenomena that it exhibits. Next, I will describe frontier areas of perovskite research, including new materials, nanomaterials, and phenomena. Finally, I will introduce the PREM team and its approach to perovskites. We will make the case for examining ionic, electronic, and magnetic structures in perovskite oxide alloys theoretically and experimentally with unprecedented accuracy. We anticipate that we will reveal novel couplings that enable a new generation of functional materials.
Orientation Domains in Anisotropic Molecular Glass Thin Films, Debaditya Chatterjee1, Shuoyuan Huang1, Kaichen Gu2,4, Junguang Yu3, Harald Bock5, Lian Yu3, Mark Ediger2, and Paul M. Voyles1, 1Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, WI, 2, Department of Chemistry, University of Wisconsin-Madison, Madison, WI,3, School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 4Exponent, New Territories, Hong Kong SAR, China, 5Centre de Recherche Paul Pascal – CNRS, Pessac, France.
Abstract: Physical vapor deposition of thin films can create glasses with an overall preferred molecular orientation. Anisotropic glasses can be made out of mesogens (molecules which exhibit liquid crystal phases) and non-mesogens (molecules without liquid crystal phases). The anisotropy arises because the surface of the growing film is highly mobile, which allows the molecules to rotate, and the film / vacuum interface tends to favor one molecular orientation. However, this process only imposes an orientation normal to the interface. In the plane of the film, the molecules form domains of similar orientation, but the global orientation averaged over many domains is isotropic. Molecular orientation effects emission and absorption of light and charge transport through these materials, so understanding and controlling both in-plane and out-of-plane orientation is important to optoelectronic applications of organic thin films.
We have used four dimensional scanning transmission electron microscopy (4D STEM) with one of the world’s fastest electron microscopy cameras to study the molecular orientation domain structure of vapor-deposited thin film glasses of a phenanthroperylene ester, a discotic mesogen known to form an equilibrium columnar hexagonal phase that favors anisotropic charge and exciton transport. 4D STEM mapping of diffraction from the intracolumnar disc stacking provides an image of the local molecular orientation at sub-nanometer spatial resolution, and the high speed reduces electron beam damage. The in-plane columnar orientation persists within domains whose length scale varies from tens of nanometers for films deposited at 12 K below the glass transition temperature Tg, to several microns for films annealed for 1 minute at Tg + 65 K, then cooled at 2.5 K/min. The boundary misorientation distribution (the distribution of the difference in molecular orientations across domain boundaries) favors angles < 2Θ°, with a shift to lower angles for films with larger domains showing a preference for low angle domain boundaries. Defects in the orientation maps are also visible. The domain size as a function of temperature is consistent with surface-diffusion limited domain growth during deposition.