Self-organizing Nano-architectured Materials: On-Demand Oral Presentations
Program Organizers: Yu-chen Karen Chen-Wiegart, Stony Brook University / Brookhaven National Laboratory; Ian Mccue, Northwestern University; Erica Lilleodden, Fraunhofer Insitute for Microstructure of Materials and Systems (IMWS); Pierre-Antoine Geslin, CNRS / INSA-Lyon; Qing Chen, Hong Kong University of Science & Technology
Monday 8:00 AM
March 14, 2022
Room: Nanostructured Materials
Location: On-Demand Room
Synthesis and Catalytical Properties of Nanoporous Copper Silver Films via Magnetron Co-sputtering: I-Chung Cheng1; Yu-Shuo Lee1; Jia-Hao Lai1; 1National Taiwan University
Nanoporous copper silver films with the average ligament size ranging from 15 to 33 nm were synthesized via magnetron co-sputtering and subsequent dealloying process. The CuAgAl precursor alloy films were selective dealloyed in 0.5M NaOH for 15 minutes. The migration of Cu and Ag nanocrystals in nanoporous structure was observed with HRTEM images. The catalytic performance of nanoporous copper silver films was determined by electrostatic double-layer capacitance and current density during CO2 reduction reaction, while the conversion products were evaluated by GC, HPLC, and NMR. The results showed that methane, ethene and ethanol, which has 6-8 electrons transfer were obtained from CO2 reduction reaction with the use of nanoporous Cu-Ag as electrocatalysts, while the faradic efficiency of hydrogen was 22%.
Biomineralized Nanocomposites: Hierarchical Structural Designs, Mechanical Properties, and Multifunctionality: Ling Li1; 1Virginia Polytechnic Institute
Many biological structural materials are highly mineralized in order to achieve their desired mechanical functions. Through the exquisite hierarchical structural organizations of the mineral building blocks together with a few percent of organic materials, these composite materials can often achieve remarkable mechanical properties, such as high strength and toughness, despite the intrinsic brittleness of the mineral constituents. In addition, the material systems can be tailored to achieve non-mechanical functions, including vision, photonic coloration, low-density, etc. Investigation of the structure-(multi-)property relationship of biomineralized composites holds important potential for guiding the development of novel multifunctional structural materials. In this talk, I will discuss our recent works in this area through a number of model systems, including mollusk shells, echinoderms, and fish teeth. I will particularly focus on their nanoscale composite designs and intrinsic mechanical properties, where these natural systems display complex structural controls that are difficult to achieve in synthetic materials.
Anomalously Low Modulus of the Interpenetrating-phase Composites Synthesized by Liquid Metal Dealloying: Ilya Okulov1; Jana Wilmers2; Pierre-Antoine Geslin3; Henry Ovri4; Soo-Hyun Joo5; Hidemi Kato6; 1Leibniz Institute for Materials Engineering - IWT; 2University of Wuppertal; 3CNRS–Université de Lyon–Tohoku University; 4Helmholtz-Zentrum Hereon; 5Dankook University; 6Institute for Materials Research, Tohoku University
Liquid metal dealloying is a modern metallurgical method enabling the synthesis of several classes of structural and functional materials: porous metals, interpenetrating-phase metallic, and hybrid (metal-polymer) composites. All these materials classes feature low elastic modulus in the range of that found for human bone as well as moderate strength values favorable for biomedical applications. Among others, metallic composites such as Ti-Mg and Fe-Mg possess anomalously low values of Young's modulus which are beyond the rule of mixtures. This deviation of elastic modulus can be explained by several mechanisms, namely, (i) the weak interfaces between immiscible bicontinuous phases promoting phase boundary sliding upon mechanical loading, (ii) interfacial distributed nanoscale porosity, and (iii) “hidden” local plastic deformation upon quasi-elastic loading regime. The micromechanical modeling demonstrated that the origin of the anomalously low modulus can be related to a weakened interface between the constituents.
Fabrication, Integration, and Performance of Nanoporous Metals In Electrochemical Energy Devices: Joshua Snyder1; 1Drexel University
The full potential of nanoporous metals in electrochemical energy storage and conversion devices has yet to be realized. This is due to a distinct disconnect between the fundamentals of nanoporous metal formation/evolution and electrochemical energy conversion device operation. Here we will present our work to bridge this gap, using a fundamental analysis of the dealloying process to optimize nanomaterial composition, compositional profile, and morphology with the goal of direct integration into full-cell electrochemical energy conversion devices including fuel cells and electrolyzers. In this work, we are able to demonstrate the utility of nanoporous metals for electrochemical energy conversion, taking advantage of their unique properties including tortuous porosity, high surface area-to-volume ratio, interconnected metallic backbone, etc. We will also present our work in understanding the evolution of nanoporous metals under relevant electrochemical conditions, deconvoluting the dominant mechanisms of mass flow, to develop mitigation strategies and improve device operational lifetime.
Nanoporous Materials for Energy and Environmental Applications: Mingwei Chen1; 1Johns Hopkins University
Bicontinuous nanoporous materials are emerging as a new class of multi-functional materials in view of their large surface areas and superior mechanical rigidity which traditional porous materials, such as metal foams, do not have. Coupled with excellent electric/thermal conductivity and rich surface chemistry for functionalization, the nanoporous materials show great promises for energy and environment related applications. In this presentation I will introduce our recent works in the development of nanoporous metals, metalloids, metallic compounds and 2D materials (graphene and transition metal dichalcogenides) by dealloying, selective phase dissolution and nanoporous metal based chemical vapor deposition. These novel nanoporous materials with 3D nanoarchitecture and tunable surface and electronic structures have been successfully employed as the catalysts, catalytic electrodes and active materials for electrochemical and photoelectrochemical hydrogen production, CO2 reduction, solar energy conversion and high-energy-density batteries.
Liquid Metal Dealloying: Formation and Coarsening: Pierre-Antoine Geslin1; Takeshi Wada2; Hidemi Kato2; 1CNRS / INSA-Lyon; 2Tohoku University
Liquid metal dealloying has emerged as a promising technique to elaborate finely porous structures of various nature. This work focus on the formation and coarsening mechanisms of microstructures obtained through the liquid metal dealloying technique. First, a phase-field model is carefully parameterized to reproduce the thermodynamics properties of Cu-Ni system dealloyed in liquid Ag. This system is chosen for simplicity reasons and the simulation results are carefully compared to experimental observations. In particular, the diffusion-limited kinetics and the progressive dissolution of Cu from the ligaments into the melt are quantitatively compared between experiments and simulations. Second, we investigate the coarsening of connected microstructures with a phase-field model incorporating surface diffusion. We show that, for different volume fractions, the topological evolution of the microstructure follows the growth of the ligament size such that the connected microstructure evolve in a self-similar way.
Processing of Nanoporous FeCr by Liquid Metal Dealloying Technique Observed by In Situ Xray Tomography and Xray Diffraction: Morgane Mokhtari1; Christophe Le Bourlot2; Jérome Adrien2; Anne Bonnin3; Wolfgang Ludwig4; Pierre-Antoine Geslin2; Takeshi Wada5; Jannick Duchet-Rumeau6; Hidemi Kato5; Eric Maire2; 1LGP, ENIT/INPT, Université de Toulouse; 2MATEIS Laboratory, INSA-Lyon; 3Swiss Light Source, Paul Scherrer Institute; 4European Synchrotron Radiation Facility; 5Institute for Materials Research, Tohoku University; 6IMP Laboratory, INSA-Lyon
Liquid metal dealloying (LMD) is a selective dissolution phenomenon of a solid alloy precursor into a metallic bath. Insoluble components spontaneously self-organize to get at room temperature a bicontinuous structure formed by the undissolved phase and solidified metallic bath phase. One phase can be removed by chemical etching to obtain the final nanoporous material. In this study, various in situ Xray experimental methods are combined to get a better understanding of the liquid metal dealloying phenomenon. FeCrx-Nix (FCC) precursors (with different x/(x+y) ratios) were dealloyed in Mg melt to obtain nanoporous FeCr (BCC). Both steps (dealloying and etching) are on the one hand, directly imaged by in situ Xray tomography, and on the other hand, followed by in situ Xray diffraction. The combination of the two different techniques gives a direct insight into not only the evolution of the morphology, but also the phase transformation and the strain field evolution.
Magnetic Nanopillars by Self-assembled Block Copolymer Templating: Alecsander Mshar1; Daniel Arnold2; Oreoluwa Agede1; Allen Owen1; Subhadra Gupta1; 1University of Alabama; 2University of Alabama at Huntsville
A designed experiment was conducted using self-assembled block copolymers to pattern multiple nanolayers of cobalt and palladium. Nanolayers ranging from four to twelve bilayers of Co (0.3 nm)/Pd (1 nm) were sputtered onto silicon wafers. The block copolymer, PS-PFS, was dissolved in toluene and spun onto the wafers. After heat treatment to phase separate the polymers, the PS was removed by oxygen plasma ashing. The remaining polymer, PFS, formed self-assembled spheres that were utilized as masks to ion mill the Co/Pd nanolayers as a function of etch time and etch angle. Scanning electron micrographs showed nanopillars ranging from 10 to 30 nm in diameter. Magnetic measurements carried out on both patterned and unpatterned wafers of these perpendicular magnetic anisotropy nanolayers and nanopillars showed an increase of 113% in coercivity after patterning. An overview of various perpendicular magnetic anisotropy materials patterned by this technique will be discussed.
A General Elastic Model for Self-Assembled Metal-oxide Vertical Aligned Nanocomposite (VAN) Thin Films: Kyle Starkey1; Ahmad Ahmad1; Juanjuan Lu1; Robynne-Lynn Paldi1; Haiyan Wang1; Anter El-Azab1; 1Purdue University West Lafayatte
In recent years in the field of nanotechnology, complex functional metal-oxide-based vertically aligned nanocomposite (VAN) thin films have gained interest due to their interesting physical properties and strong anisotropy. Despite the experimental demonstrations of various metal-oxide VAN films, modeling efforts that capture the complex two-phase structures and the mechanical coupling along the interfaces are very scarce. We present a new model that simulates the elastic deformation of two-phase nanocomposites and the mechanical coupling as a function of the interfacial density of pillar/matrix, pillar/substrate, and matrix/substrate, considering the epitaxial relationships between the two phases. The model accounts for the lattice mismatch between materials, curvature effects at the interface, and common line forces at the intersection of phase boundaries using concentrated surface and line body forces. The model can be used to predict a favorable potential two-phase system for future experimental demonstrations by calculating the total thermodynamic energy of different film morphologies.
Superinsulation Nanoporous Material, Silica and Biosourced Aerogels Observed in 3D Down to the Nanoscale with Electron Tomography: Genevieve Foray1; Louis-marie Lebas1; Lucian Roiban1; 1MATEIS, INSA Lyon
Assessing the efficiency of super-insulation products is a key step before they can become widespread in the building, or in transportation industry. Cutting edge techniques, such as electron and x ray tomography are of interest. They provide both, 3D images and 3D quantification of the pore and particles network. Thus, confidence increase in texture and properties relationship. We shade light on benefits and limitation of Fast electron tomography dedicated to highly beam sensitive materialsOur study focuses on silica aerogels and biomass aerogels and aims at quantifying the materials nanostructure. They differ in their chemistry (intentionally hydrophobized silica, natural polymer), in their synthesis processes, but also in properties such as thermal conductivity or specific surfaces. Pore size distribution and connectivity are discussed. Image analysis tools used to treat tomography prior to quantification are explained, as well as specificity due to the low contrast.
Hierarchical Grain Structure in Low Stacking-fault Energy Metals for Highly Tough Nanoporous Metal: Eunji Song1; Hansol Jeon1; Ju-Young Kim1; 1Department of Materials Science and Engineering, UNIST
Nanoporous metal is material with sponge-like structure, composed of continuously connected ligament and pore at nanoscale, which gives low density and high surface-to-volume ratio. These properties provide the advantages of application for catalyst, actuator, and sensor. However, though gold is ductile metal at bulk scale, brittle fracture occurs in nanoporous gold (np-Au) by stress concentration on pore surface and catastrophic crack propagation through grain boundaries. In this study, we focus on designing hierarchical grain boundaries as detoured crack propagation path. We perform cyclic hot-rolling and intermediate annealing on Au-Ag alloy. Hierarchical grain structure evolves at micron scale by interaction of shear band and deformation twin, and hierarchical np-Au forms as Ag is selectively etched by free-corrosion dealloying in nitric acid. Fracture toughness, KⅠc and KJc is investigated on coarse grained, fine grained, and hierarchical grained np-Au, and we discuss effect of grain boundary structure on fracture toughness and crack propagation.