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Ramírez-Ramírez F, Flores-Olmedo E, Báez G, Sadurní E, Méndez-Sánchez RA. Emulating tightly bound electrons in crystalline solids using mechanical waves. Sci Rep 2020; 10:10229. [PMID: 32576887 PMCID: PMC7311533 DOI: 10.1038/s41598-020-67108-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Accepted: 05/28/2020] [Indexed: 11/15/2022] Open
Abstract
Solid state physics deals with systems composed of atoms with strongly bound electrons. The tunneling probability of each electron is determined by interactions that typically extend to neighboring sites, as their corresponding wave amplitudes decay rapidly away from an isolated atomic core. This kind of description is essential in condensed-matter physics, and it rules the electronic transport properties of metals, insulators and many other solid-state systems. The corresponding phenomenology is well captured by tight-binding models, where the electronic band structure emerges from atomic orbitals of isolated atoms plus their coupling to neighboring sites in a crystal. In this work, a mechanical system that emulates dynamically a quantum tightly bound electron is built. This is done by connecting mechanical resonators via locally periodic aluminum bars acting as couplers. When the frequency of a particular resonator lies within the frequency gap of a coupler, the vibrational wave amplitude imitates a bound electron orbital. The localization of the wave at the resonator site and its exponential decay along the coupler are experimentally verified. The quantum dynamical tight-binding model and frequency measurements in mechanical structures show an excellent agreement. Some applications in atomic and condensed matter physics are suggested.
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Affiliation(s)
- F Ramírez-Ramírez
- Posgrado en Ciencias e Ingeniería, División de Ciencias Básicas e Ingeniería, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200, Ciudad de México, Mexico
| | - E Flores-Olmedo
- Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200, Ciudad de México, Mexico
| | - G Báez
- Departamento de Ciencias Básicas, Universidad Autónoma Metropolitana-Azcapotzalco, Av. San Pablo 180, Col. Reynosa Tamaulipas, 02200, Ciudad de México, Mexico
| | - E Sadurní
- Instituto de Física, Benemérita Universidad Autónoma de Puebla, Apartado Postal J-48, 72570, Puebla, Mexico
| | - R A Méndez-Sánchez
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, 62210, Cuernavaca Mor., Mexico.
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Kang E, Kim H, Gray LAG, Christie D, Jonas U, Graczykowski B, Furst EM, Priestley RD, Fytas G. Ultrathin Shell Layers Dramatically Influence Polymer Nanoparticle Surface Mobility. Macromolecules 2018; 51:8522-8529. [PMID: 30906073 PMCID: PMC6428372 DOI: 10.1021/acs.macromol.8b01804] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Revised: 10/01/2018] [Indexed: 01/27/2023]
Abstract
Advances in nanoparticle synthesis, self-assembly, and surface coating or patterning have enabled a diverse array of applications ranging from photonic and phononic crystal fabrication to drug delivery vehicles. One of the key obstacles restricting its potential is structural and thermal stability. The presence of a glass transition can facilitate deformation within nanoparticles, thus resulting in a significant alteration in structure and performance. Recently, we detected a glassy-state transition within individual polystyrene nanoparticles and related its origin to the presence of a surface layer with enhanced dynamics compared to the bulk. The presence of this mobile layer could have a dramatic impact on the thermal stability of polymer nanoparticles. Here, we demonstrate how the addition of a shell layer, as thin as a single polymer chain, atop the nanoparticles could completely eliminate any evidence of enhanced mobility at the surface of polystyrene nanoparticles. The ultrathin polymer shell layers were placed atop the nanoparticles via two approaches: (i) covalent bonding or (ii) electrostatic interactions. The temperature dependence of the particle vibrational spectrum, as recorded by Brillouin light scattering, was used to probe the surface mobility of nanoparticles with and without a shell layer. Beyond suppression of the surface mobility, the presence of the ultrathin polymer shell layers impacted the nanoparticle glass transition temperature and shear modulus, albeit to a lesser extent. The implication of this work is that the core-shell architecture allows for tailoring of the nanoparticle elasticity, surface softening, and glass transition temperature.
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Affiliation(s)
- Eunsoo Kang
- Max Planck Institute
for Polymer Research, Ackermannweg
10, 55128 Mainz, Germany
| | - Hojin Kim
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Laura A. G. Gray
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Dane Christie
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - Ulrich Jonas
- Macromolecular
Chemistry, Department of Chemistry and Biology, University of Siegen, Adolf-Reichwein-Strasse 2, 57076 Siegen, Germany
| | | | - Eric M. Furst
- Department
of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, United States
| | - Rodney D. Priestley
- Department
of Chemical and Biological Engineering, Princeton University, Princeton, New Jersey 08544, United States
| | - George Fytas
- Max Planck Institute
for Polymer Research, Ackermannweg
10, 55128 Mainz, Germany
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Kim H, Cang Y, Kang E, Graczykowski B, Secchi M, Montagna M, Priestley RD, Furst EM, Fytas G. Direct observation of polymer surface mobility via nanoparticle vibrations. Nat Commun 2018; 9:2918. [PMID: 30046038 PMCID: PMC6060150 DOI: 10.1038/s41467-018-04854-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 05/24/2018] [Indexed: 11/08/2022] Open
Abstract
Measuring polymer surface dynamics remains a formidable challenge of critical importance to applications ranging from pressure-sensitive adhesives to nanopatterning, where interfacial mobility is key to performance. Here, we introduce a methodology of Brillouin light spectroscopy to reveal polymer surface mobility via nanoparticle vibrations. By measuring the temperature-dependent vibrational modes of polystyrene nanoparticles, we identify the glass-transition temperature and calculate the elastic modulus of individual nanoparticles as a function of particle size and chemistry. Evidence of surface mobility is inferred from the first observation of a softening temperature, where the temperature dependence of the fundamental vibrational frequency of the nanoparticles reverses slope below the glass-transition temperature. Beyond the fundamental vibrational modes given by the shape and elasticity of the nanoparticles, another mode, termed the interaction-induced mode, was found to be related to the active particle-particle adhesion and dependent on the thermal behavior of nanoparticles.
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Affiliation(s)
- Hojin Kim
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA
| | - Yu Cang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Eunsoo Kang
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
| | - Bartlomiej Graczykowski
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany
- NanoBioMedical Centre, Adam Mickiewicz University, ul. Umultowska 85, Poznan, 61-614, Poland
| | - Maria Secchi
- Department of Industrial Engineering, University of Trento, 38123, Trento, Italy
| | | | - Rodney D Priestley
- Department of Chemical and Biological Engineering, Princeton University, Princeton, NJ, 08544, USA
| | - Eric M Furst
- Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, DE, 19716, USA.
| | - George Fytas
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
- IESL-FORTH, N. Plastira 100, 70013, Heraklion, Crete, Greece.
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Beltramo PJ, Schneider D, Fytas G, Furst EM. Anisotropic hypersonic phonon propagation in films of aligned ellipsoids. PHYSICAL REVIEW LETTERS 2014; 113:205503. [PMID: 25432048 DOI: 10.1103/physrevlett.113.205503] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2014] [Indexed: 05/24/2023]
Abstract
A material with anisotropic elastic mechanical properties and a direction-dependent hypersonic band gap is fabricated using ac electric field-directed convective self-assembly of colloidal ellipsoids. The frequency of the gap, which is detected in the direction perpendicular to particle alignment and entirely absent parallel to alignment, and the effective sound velocities can be tuned by the particle aspect ratio. We hypothesize that the band gap originates from the primary eigenmode peak, the m-splitted (s,1,2) mode, of the particle resonating with the effective medium. These results reveal the potential for powerful control of the hypersonic phononic band diagram by combining anisotropic particles and self-assembly.
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Affiliation(s)
- Peter J Beltramo
- Department of Chemical & Biomolecular Engineering, Center for Molecular and Engineering Thermodynamics, University of Delaware, Newark, Delaware 19716, USA
| | - Dirk Schneider
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - George Fytas
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany and Department of Materials Science, University of Crete and IESL-FORTH, 71110 Heraklion, Greece
| | - Eric M Furst
- Department of Chemical & Biomolecular Engineering, Center for Molecular and Engineering Thermodynamics, University of Delaware, Newark, Delaware 19716, USA
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Sirotkin S, Mermet A, Bergoin M, Ward V, Van Etten JL. Viruses as nanoparticles: structure versus collective dynamics. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2014; 90:022718. [PMID: 25215769 DOI: 10.1103/physreve.90.022718] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2014] [Indexed: 06/03/2023]
Abstract
In order to test the application of the "nanoparticle" concept to viruses in terms of low-frequency dynamics, large viruses (140-190 nm) were compared to similar-sized polymer colloids using ultra-small-angle x-ray scattering and very-low-frequency Raman or Brillouin scattering. While both viruses and polymer colloids show comparable highly defined morphologies, with comparable abilities of forming self-assembled structures, their respective abilities to confine detectable acoustic vibrations, as expected for such monodisperse systems, differed. Possible reasons for these different behaviors are discussed.
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Affiliation(s)
- S Sirotkin
- Institut Lumière Matière, Université de Lyon, Université Claude Bernard Lyon 1, UMR CNRS 5306, 69622 Villeurbanne, France
| | - A Mermet
- Institut Lumière Matière, Université de Lyon, Université Claude Bernard Lyon 1, UMR CNRS 5306, 69622 Villeurbanne, France
| | - M Bergoin
- Laboratoire de Virologie Comparé des Invertébrés, E.P.H.E., Université Montpellier 2, France
| | - V Ward
- University of Otago, Department of Microbology and Immunology, New Zealand
| | - J L Van Etten
- Department of Plant Pathology and the Nebraska Center for Virology, University of Nebraska-Lincoln, Lincoln, Nebraska USA
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