Bulletin of the American Physical Society
APS March Meeting 2019
Volume 64, Number 2
Monday–Friday, March 4–8, 2019; Boston, Massachusetts
Session R32: Solvation and NanofluidicsFocus
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Sponsoring Units: DCP Chair: Dario Corradini, American Physical Society APS Room: BCEC 204A |
Thursday, March 7, 2019 8:00AM - 8:12AM |
R32.00001: The Intrinsic Density of a Nanoconfined Liquid Samuel Cohen, John S Bender, Benoit Coasne, John T Fourkas Liquids confined to nanoscale geometries are ubiquitous in nature and important in many areas of science and technology. However, connecting the microscopic structure and dynamics of a confined liquid to its macroscopic behavior is a fundamental, unsolved problem in liquid-state physics. One key macroscopic property, the density, is highly fluid- dependent, and there is currently no rigorous way of assessing a confined liquid’s accessible volume. Here we present our work using the spectrum of intermolecular vibrational modes to probe the intrinsic density of a confined liquid. In particular, molecular simulations to probe the density will be discussed. |
Thursday, March 7, 2019 8:12AM - 8:24AM |
R32.00002: Uniaxial-deformation behavior of Ice Ih as described by the TIP4P/Ice and mW water models Maurice De Koning, Pedro Antonio Santos-Flórez, Carlos Javier Ruestes Using molecular dynamics simulations we assess the uniaxial deformation response of ice Ih as described by two popular water models, namely the all-atom TIP4P/Ice potential and the coarse-grained mW model. In particular, we investigate the response to both tensile and compressive uniaxial deformations along the [0001] and [0-110] crystallographic directions for a series of different temperatures. We classify the respective failure mechanisms and assess their sensitivity to strain rate and cell size. While the TIP4P/Ice model fails by either brittle cleavage under tension at low temperatures or large-scale amorphization/melting, the mW potential behaves in a much more ductile manner, displaying numerous cases in which stress relief involves the nucleation and subsequent activity of lattice dislocations. Indeed, the fact that mW behaves in such a malleable manner even at strain rates that are substantially higher than those applied in typical experiments indicates that the mW description of ice Ih is excessively ductile. One possible contribution to this enhanced malleability is the absence of explicit protons in the mW model, disregarding the fundamental asymmetry of the hydrogen bond that plays an important role in the nucleation and motion of lattice dislocations in ice Ih. |
Thursday, March 7, 2019 8:24AM - 8:36AM |
R32.00003: Theory of freezing point depression and materials damage by nano-fluidic salt trapping Edmond Zhou, Mohammad Mirzadeh, Roland JM Pellenq, Martin Bazant The electrolyte solution inside the pore space of many functional materials are subjected to freeze-thaw cycles in a cold season, often undermining the material structure and eventually leading to failure. For more durable designs, it is crucial to understand the interplay between pore surface charge, salt ions and pore connectivity during freezing. We present a continuum theory to distinguish nano-fluidic confined freezing from open systems, and calculate freezing point depression, supercooling and pressure in both limits. As an example application, we provide a possible explaination for the mechanism of freeze-thaw damage in cement paste. Our findings could also provide some insights for cryopreservation and survival of species in winter. |
Thursday, March 7, 2019 8:36AM - 8:48AM |
R32.00004: Nuclear quantum effects on the liquid–liquid phase transition of a water-like monatomic liquid Nicolas Giovambattista, Gustavo E Lopez, Binh Nguyen Polyamorphic substances have the ability to exist in more than one liquid and/or glass states. Examples include water, silicon, and hydrogen. In many of these substances, nuclear quantum effects may become important in the proximity of the liquid–liquid and glass–glass transformation. Here, we study the nuclear quantum effects on a monatomic liquid that exhibits water-like anomalous properties and a liquid–liquid phase transition (LLPT) ending at a liquid–liquid critical point (LLCP). By performing path integral Monte Carlo simulations with different values of the Planck’s constant h, we are able to explore how the location of the LLCP/LLPT in the P–T plane shifts as the system evolves from classical, h = 0, to quantum, h > 0. We find that, as the quantum nature of the liquid (as quantified by h) increases, and the atoms in the liquid become more delocalized, the LLCP pressure increases, the LLCP temperature decreases, and the LLCP volume remains constant. In addition, the crystallization temperature decreases with increasing h. For large values of h, the LLCP is not accessible due to rapid crystallization. The structure of the liquids studied at different values of h are also investigated. |
Thursday, March 7, 2019 8:48AM - 9:00AM |
R32.00005: Strain-Induced Raman Shifts Due to Ice Adhesion Subash Kattel, Joseph Murphy, Marina Machado de Oliveira, Samuel Pasco, John Ackerman, Vladimir Alvarado, William Rice Ice formed on a material creates a strain that is indicative of the adhesive strength between the ice and substrate. Previous determinations of ice adhesion strength, a critical parameter for understanding icing physics, have proven to be both challenging and highly dependent on experiment-specific conditions (surface roughness, icing conditions, water purity, etc.). In this work, we use Raman spectroscopy to contactlessly and non-destructively measure ice-induced strain on silicon and single-layer graphene. To isolate the ice-material interface, we measured the vibrational modes of graphene from 200C to - 30 0C with and without ice. Along with the well-known temperature-dependent Raman shift of graphene, a clear, ~ 3 cm-1 change in the G-mode (~1590 cm-1) frequency developed upon ice formation. We found this change in the Raman shift tracked closely to the temperature-dependent density of ice, suggesting that we are optically measuring ice-created strain in graphene. When correlated with mechanical adhesion measurements, our non-destructive optical technique provides a way to measure ice adhesive strength, which can be extended to various materials. |
(Author Not Attending)
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R32.00006: Size and Aggregation of Ice-binding Proteins Control Their Ice Nucleation Efficiency Yuqing Qiu, Arpa Hudait, Valeria Molinero Ice-binding proteins are the common name shared by antifreeze proteins (AFPs) and ice nucleating proteins (INPs). It has been proposed that the size of ice-binding surface determines the function of these proteins, as INPs or AFPs. Aggregation of proteins can create large ice-binding surfaces, stabilize larger ice nucleus and enhance ice nucleation, However, the quantitative dependence of ice nucleation ability on the size and aggregation of the ice-binding surfaces has not yet been elucidated. We use molecular dynamic simulations to show that the ice nucleating ability of a ice-binding protein increases with their length and saturates at an ice freezing temperature lower that that induced by INP aggregates, because the short dimension of small ice-binding surface limits the formation of ice nucleus. We further demonstrate that INPs dimer with specific separation distance enhances the ice nucleating ability of INPs. We conclude that the size and aggregation of ice-binding proteins control their efficiencies. |
Thursday, March 7, 2019 9:12AM - 9:24AM |
R32.00007: Wetting state transition of water droplet on graphene surface with nanoscale pillars Hongru Ren, Chun Li The regulation of solid surface wettability can be effectively achieved by controlling surface microstructure and external |
Thursday, March 7, 2019 9:24AM - 9:36AM |
R32.00008: Surface Adsorption and Encapsulated Storage of H2 Molecules in a Cagelike (MgO)12 Cluster Yan Zhang, Hongshan Chen The cluster with a cagelike structure could enable the storage of H2 molecules via surface adsorption and encapsulated storage. Surface adsorption involves the interaction between H2 and host clusters. Encapsulated storage involves the storage of H2 in the interior space of the cagelike structure. The latter is essential for practical applications of cagelike clusters because the interior space is retained when they are assembled into solid-state materials, although many surface adsorption sites are occupied. Here, we report an investigation on surface adsorption and encapsulated storage of H2 molecules in the cagelike (MgO)12 cluster based on a dispersion-corrected density functional theory calculation. The results revealed that the cagelike (MgO)12 cluster surface can adsorb 24 H2 molecules with an average adsorption energy of 0.116 eV/H2, which brings about a gravimetric density of 9.1 wt%. Inside the cagelike (MgO)12 cluster, a maximum capacity of six H2 molecules could be stored according to symmetric configurations. The encapsulated H2 molecules are trapped by energy barriers no more than 2.55 eV, although the storage is an endothermic process. |
Thursday, March 7, 2019 9:36AM - 9:48AM |
R32.00009: WITHDRAWN ABSTRACT
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Thursday, March 7, 2019 9:48AM - 10:00AM |
R32.00010: Liquid and solid solute encapsulation using the Ouzo effect: the magic of phase diagrams Francois Ganachaud, Xibo YAN, Julien Bernard Nanoprecipitation is a powerful spontaneous emulsification technique known for long to generate polymeric particles and capsules. Nevertheless, only recently was this solvent shifting technique rationalize into phase diagrams, giving both a meaning for the physical chemistry of dispersion formation (nluceation/agregation growing process) and a rational for the different solutes that can be precipitated using this technique (e.g. oils, solid molecules, lipids, polymers). |
Thursday, March 7, 2019 10:00AM - 10:12AM |
R32.00011: Blue Shift of a Molecular Crystal Phonon at the Solid to Liquid Phase Transition Alex Davie, Farah Vandrevala, Yanting Deng, Deepu George, Eric Sylvester, Timothy Korter, Erik Einarsson, Jason Benedict, Andrea Markelz We investigate the dielectric response from the optically active phonons of single-crystal fructose using terahertz (THz) spectroscopic techniques. All samples were indexed by x-ray diffraction with space group of P212121, lattice constants a = 8.09 Å, b = 9.21 Å, c = 10.03 Å and α = β = γ = 90°. Anisotropic THz absorbance unambiguously assigns the measured resonances to specific lattice vibrations calculated by density functional theory. Using [101] face polished crystals, the lowest frequency resonance polarized along the b axis at 1.70 THz is found to continuously red shift with heating to 1.59 THz at the melting temperature 103°C. As the sample is maintained at 103°C the resonance continues to red shift, broaden and decrease in amplitude with melting. Using [010] face polished crystals, the lowest frequency resonance polarized along the c axis at 1.31 THz is found to red shift with heating to 1.25 THz at 103°C, but then blue shifts to 1.26 THz as the temperature is held at 103°C. The peak then remains at this frequency, broadens and decreases in amplitude as the sample enters the liquid phase. The result is inconsistent with expected softening of intermolecular forces during the phase transition. |
Thursday, March 7, 2019 10:12AM - 10:24AM |
R32.00012: Caged Contact Pair Formation in Cooled Triiodide-Ethanol Solutions Frank Yi Gao, Yu-Hsiang Cheng, Keith Adam Nelson We have conducted spectrally-resolved optical pump-probe experiments following the photodissociation of triiodide (I3-) in cooled ethanol solutions from 300 K to 80 K. After being excited by a UV pump pulse at 400 nm, I3- dissociates into I2- and I fragments, the former of which is monitored by its broad absorption in the 660-870 nm range. Primary geminate recombination occurs within 4 ps over the temperature range studied and occurs in an increasing fraction of photofragments as the solution is cooled. Following an initial period of vibrational relaxation, the observed spectra continuously red-shifts with decreasing temperature before saturating near 800 nm below 160 K. The red-shifted band appears on a timescale similar to geminate recombination. These results are consistent with the increased formation of a caged contact pair species at low temperatures. |
Thursday, March 7, 2019 10:24AM - 10:36AM |
R32.00013: Capillary condensation in the atomic-scale slits Qian Yang, Andre Geim Capillary condensation determines fundamentally the adhesion, nucleation, adsorption and friction processes in all granular and porous materials, micromechanical devices and nanotechnology, even in living systems. Its theoretical basis-the Kelvin equation, whose cogency has long been questioned on the nanoscale, is under continuously debate. Consensus has been reached on the validity of the Kelvin equation down to 4 nm, but pores and cracks in nature do not stop their extending to the molecular dimensions. Up to now, little information, at least experimentally, is available at the molecular scale. Here we report water condensation in ultimately thin capillaries, which is capable of accommodate only one layer of water molecules. Pronounced deviations are observed under strong confinement less than 2 nm. Theoretical interpretation of changes in the solid-liquid surface energy resulting from rearranging the water structure near a particular surface complements the Kelvin equation in the ultimate limit of the atomic-scale confinement. |
Thursday, March 7, 2019 10:36AM - 10:48AM |
R32.00014: Thermodynamics-based electrochemistry transport models: theory and applications Maxim Zyskin I will describe Newman-Monroe thermodynamics-based eletrochemical transport models and new results on numerical modeling and molecular dynamics based parameter estimation in such models. This work has applications to modeling multiphysics processes in solid electrolythes and is a part of a program of research on electric batteries. |
Thursday, March 7, 2019 10:48AM - 11:00AM |
R32.00015: Curvature Dependence of Surface Tension and Test of Kelvin Equation at Molecular Scale Seongsoo Kim, Dohyun Kim, Jongwoo Kim, Sangmin An, Wonho Jhe Capillary condensation is the vapo r-to-liquid phase transition occurring in confined geometries. Such heterogeneous nucleation has been well described by the Kelvin equation, but its applicability at nanoscale is still unresolved. We show it is valid down to 0.5 nm scale when the curvaturedependent surface tension is considered. Our results that unify the validity of the Kelvin equation and the curvature effect of surface tension may provide a better understanding of nucleation phenomena. |
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