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Pawlak A, Krajenta J. Entanglements of Macromolecules and Their Influence on Rheological and Mechanical Properties of Polymers. Molecules 2024; 29:3410. [PMID: 39064989 PMCID: PMC11280004 DOI: 10.3390/molecules29143410] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2024] [Revised: 07/11/2024] [Accepted: 07/17/2024] [Indexed: 07/28/2024] Open
Abstract
Flexible macromolecules easily become entangled with neighboring macromolecules. The resulting network determines many polymer properties, including rheological and mechanical properties. Therefore, a number of experimental and modeling studies were performed to describe the relationship between the degree of entanglement of macromolecules and polymer properties. The introduction presents general information about the entanglements of macromolecule chains, collected on the basis of studies of equilibrium entangled polymers. It is also shown how the density of entanglements can be reduced. The second chapter presents experiments and models leading to the description of the movement of a single macromolecule. The next part of the text discusses how the rheological properties change after partial disentangling of the polymer. The results on the influence of the degree of chain entanglement on mechanical properties are presented.
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Affiliation(s)
- Andrzej Pawlak
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, 90-363 Lodz, Poland;
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2
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Clarke N, Buxton GA. Modeling photo-generated charge extraction in bulk heterojunction nanoparticles. SOFT MATTER 2024; 20:1651-1656. [PMID: 38284130 DOI: 10.1039/d3sm01352a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2024]
Abstract
We present a drift-diffusion model for predicting currents generated through the absorption of solar energy inside bulk heterojunction organic nanoparticles, which are, for example, promising nanomaterials for photo-catalytic water splitting. By coupling a model of the internal microstructure of the nanoparticle with the electronic properties, we show how different characteristics of the microstructure influence the efficiency of the conversion of solar energy into electrical energy. Our model provides a foundation for using computational modeling to optimize the design of photocatalytic nanoparticles.
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Affiliation(s)
- Nigel Clarke
- Department of Physics and Astronomy, University of Sheffield, S3 7RH, Sheffield, UK.
| | - Gavin A Buxton
- Science Department, Robert Morris University, Moon Township, PA 15108, USA
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3
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Mohottalalage SS, Kosgallana C, Senanayake M, Wijesinghe S, Osti NC, Perahia D. Molecular Insight into the Effects of Clustering on the Dynamics of Ionomers in Solutions. ACS Macro Lett 2023; 12:1118-1124. [PMID: 37493602 DOI: 10.1021/acsmacrolett.3c00353] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/27/2023]
Abstract
Ionizable groups tethered to polymers enable their many current and potential applications. However, these functionalities drive the formation of physical networks through clustering of the ionic groups, resulting in constrained dynamics of the macromolecules. Understanding the molecular origin of this hindrance remains a critical fundamental question, whose solution will directly impact the processing of ionizable polymers from molecules to viable materials. Here, using quasielastic neutron scattering accompanied by molecular dynamics simulations, segmental dynamics of slightly sulfonated polystyrene is studied in solutions as the cohesion of the ionic assemblies is tuned. We find that in cyclohexane the ionic assemblies act as centers of confinement, affecting dynamics both on macroscopic lengths and in the vicinity of the ionic assemblies. Addition of a small amount of ethanol affects the packing of the ionizable groups within the assemblies, which in turn enhances the chain dynamics.
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Affiliation(s)
- Supun S Mohottalalage
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Chathurika Kosgallana
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
| | - Manjula Senanayake
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Sidath Wijesinghe
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
- Department of Chemistry, Appalachian State University, Boone, North Carolina 26808, United States
| | - Naresh C Osti
- Neutron Scattering Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, United States
| | - Dvora Perahia
- Department of Chemistry, Clemson University, Clemson, South Carolina 29634, United States
- Department of Physics, Clemson University, Clemson, South Carolina 29631, United States
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4
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Demydiuk F, Solar M, Meyer H, Benzerara O, Paul W, Baschnagel J. Role of torsional potential in chain conformation, thermodynamics, and glass formation of simulated polybutadiene melts. J Chem Phys 2022; 156:234902. [PMID: 35732513 DOI: 10.1063/5.0094536] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
For polymer chains, the torsional potential is an important intramolecular energy influencing chain flexibility and segmental dynamics. Through molecular dynamics simulations of an atomistic model for melts of cis-trans-1,4-polybutadiene (PBD), we explore the effect of the torsions on conformational properties (bond vector correlations and mean-square internal distances), fundamental thermodynamic quantities (density, compressibility, internal energy, and specific heat), and glass transition temperature Tg. This is achieved by systematically reducing the strength of the torsional potential, starting from the chemically realistic chain (CRC) model with the full potential toward the freely rotating chain (FRC) model without the torsional potential. For the equilibrium liquid, we find that the effect of the torsions on polymer conformations is very weak. Still weaker is the influence on the monomer density ρ and isothermal compressibility κT of the polymer liquid, both of which can be considered as independent of the torsional potential. We show that a van der Waals-like model proposed by Long and Lequeux [Eur. Phys. J. E 4, 371 (2001)] allows us to describe very well the temperature (T) dependence of ρ and κT. We also find that our data obey the linear relation between 1/kBTρκT and 1/T (with the Boltzmann constant kB) that has recently been predicted and verified on the experiment by Mirigian and Schweizer [J. Chem. Phys. 140, 194507 (2014)]. For the equilibrium liquid, simulations result in a specific heat, at constant pressure and at constant volume, which increases on cooling. This T dependence is opposite to the one found experimentally for many polymer liquids, including PBD. We suggest that this difference between simulation and experiment may be attributed to quantum effects due to hydrogen atoms and backbone vibrations, which, by construction, are not included in the classical united-atom model employed here. Finally, we also determine Tg from the density-temperature curve monitored in a finite-rate cooling process. While the influence of the torsional potential on ρ(T) is vanishingly small in the equilibrium liquid, the effect of the torsions on Tg is large. We find that Tg decreases by about 150 K when going from the CRC to the FRC model.
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Affiliation(s)
- F Demydiuk
- Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22, F-67000 Strasbourg, France
| | - M Solar
- Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22, F-67000 Strasbourg, France
| | - H Meyer
- Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22, F-67000 Strasbourg, France
| | - O Benzerara
- Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22, F-67000 Strasbourg, France
| | - W Paul
- Institut für Physik, Martin Luther Universität, D-06099 Halle, Germany
| | - J Baschnagel
- Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22, F-67000 Strasbourg, France
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5
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Ultrafast dynamics of proflavine bound to poly (methacrylic acid) in aqueous solution. J Mol Struct 2022. [DOI: 10.1016/j.molstruc.2022.132676] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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A Brief Overview of Polymers Science and Technology, in Spain. Polymers (Basel) 2022; 14:polym14040652. [PMID: 35215565 PMCID: PMC8876667 DOI: 10.3390/polym14040652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2021] [Revised: 01/28/2022] [Accepted: 01/30/2022] [Indexed: 02/01/2023] Open
Abstract
This Special Issue State-of-the-Art on Polymer Science and Technology in Spain is comprised of a collection of 42 publications/contributions related to very different topics undertaken by the numerous research groups working in Spain in Polymer Science and Technology. This monograph collects the contributions of more than 200 different authors from 24 different national Institutions (>30 different centers/departments) from Universities and CSIC centers distributed throughout the whole of Spain. Two-thirds of the contributions to this Special Issue arise from Institutional collaborations, half of which are international collaborations with European research groups and the other half with other international research groups outside Europe including China, Australia or United States of America among others. This brief overview communication provides a general overview of the research lines in Polymer Science and Technology covered in Spain and show most of the representative polymer groups and their distribution throughout Spain. Most of Spanish polymer groups belong to the Grupo Especializado de Polímeros (GEP) being part of the European Polymer Federation (EPF). It also shows how Spanish science about polymers is positioned at European level.
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Design, Preparation, and Evaluation of Enteric Coating Formulation of HPMC and Eudragit L100 on Carboxylated Agarose Hydrogel by Using Drug Tartrazine. BIOMED RESEARCH INTERNATIONAL 2022; 2022:1042253. [PMID: 35127935 PMCID: PMC8816555 DOI: 10.1155/2022/1042253] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2021] [Revised: 12/28/2021] [Accepted: 01/15/2022] [Indexed: 11/17/2022]
Abstract
Enteric-coated application on drug is used to prevent the drug from inactivation which are degraded by gastric enzyme. The present study is aimed at achieving controlled drug delivery in acidic medium of gastrointestinal tract (GIT) by enteric coating of hydroxy propyl methylcellulose (HPMC) and Eudragit L100 on carboxylated agarose hydrogel, creating a pH-dependent delivery system. Fourier-transformed infrared spectroscopy (FTIR) was for the detection of carboxylic group on agarose hydrogel, and scanning electron microscope (SEM) was used for the determination surface of prepared formulation. To check the pH sensitivity of enteric-coated formulation, different pH solution was used. It was found that the formulation was not dissolved in 1.2 but dissolve in pH 6.8 similarly; hydrogels lacking coating showed that tartrazine was more dissolved in pH 1.2, and less dissolved at pH 6.8. The release of tartrazine from the hydrogels was measured by using spectrophotometer and using a scanning electron microscope to examine the morphology and surface appearance of hydrogel capsules. This study revealed cracks on coated samples, while noncoated samples showed clear appearance with no cracks. Our findings revealed that this method could be useful for the development of an enteric coating drug delivery system.
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Nemkovski K, Bewley R, García Sakai V, Nilsen GJ, Perrichon A, Silverwood I. SHERPA: A Spectrometer with High Energy Resolution and Polarisation Analysis. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227202004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
SHERPA is a proposed quasielastic neutron spectrometer with polarisation analysis, intended to replace the ageing Iris instrument at the ISIS neutron and muon source. In this paper we present a concept of the instrument along with Monte-Carlo simulations and analysis of possible instrument location. We expect greatly increased count rate compared to Iris (expected from 49 to 660 × Iris) in unpolarised mode and dedicated polarisation analysis capabilities at a more modest count rate increase (~5-70 × Iris). This huge gain in the count rate would be achieved from the combination of three factors: modern neutron guide with high-m coating, and prismatic effect and larger solid angle coverage at the energy analyser. Such an instrument would be the first of its kind and has incredible potential to revolutionise quasielastic neutron scattering technique through the separation of the coherent and incoherent scattering contributions.
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Reich V, Majumdar A, Müller M, Busch S. Comparison of molecular dynamics simulations of water with neutron and X-ray scattering experiments. EPJ WEB OF CONFERENCES 2022. [DOI: 10.1051/epjconf/202227201015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The atomistic structure and dynamics obtained from molecular dynamics (MD) simulations with the example of TIP3P (rigid and flexible) and TIP4P/2005 (rigid) water is compared to neutron and X-ray scattering data at ambient conditions. Neutron and X-ray diffractograms are calculated from the simulations for four isotopic substitutions as well as the incoherent intermediate scattering function for neutrons. The resulting curves are compared to each other and to published experimental data. Differences between simulated and measured intermediate scattering functions are quantified by fitting an analytic model to the computed values. The sensitivity of the scattering curves to the parameters of the MD simulations is demonstrated on the example of two parameters, bond length and angle.
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Wolf CM, Guio L, Scheiwiller S, Pakhnyuk V, Luscombe C, Pozzo LD. Strategies for the Development of Conjugated Polymer Molecular Dynamics Force Fields Validated with Neutron and X-ray Scattering. ACS POLYMERS AU 2021; 1:134-152. [PMID: 36855657 PMCID: PMC9954299 DOI: 10.1021/acspolymersau.1c00027] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Conjugated polymers (CPs) enable a wide range of lightweight, lower cost, and flexible organic electronic devices, but a thorough understanding of relationships between molecular structure and dynamics and electronic performance is critical for improved device efficiencies and for new technologies. Molecular dynamics (MD) simulations offer in silico insight into this relationship, but their accuracy relies on the approach used to develop the model's parameters or force field (FF). In this Perspective, we first review current FFs for CPs and find that most of the models implement an arduous reparameterization of inter-ring torsion potentials and partial charges of classical FFs. However, there are few FFs outside of simple CP molecules, e.g., polythiophenes, that have been developed over the last two decades. There is also limited reparameterization of other parameters, such as nonbonded Lennard-Jones interactions, which we find to be directly influenced by conjugation in these materials. We further provide a discussion on experimental validation of MD FFs, with emphasis on neutron and X-ray scattering. We define multiple ways in which various scattering methods can be directly compared to results of MD simulations, providing a powerful experimental validation metric of local structure and dynamics at relevant length and time scales to charge transport mechanisms in CPs. Finally, we offer a perspective on the use of neutron scattering with machine learning to enable high-throughput parametrization of accurate and experimentally validated CP FFs enabled not only by the ongoing advancements in computational chemistry, data science, and high-performance computing but also using oligomers as proxies for longer polymer chains during FF development.
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Affiliation(s)
- Caitlyn M. Wolf
- Department
of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195-1750, United States,Center
for Neutron Research, Stop 6102, National
Institute of Standards and Technology, Gaithersburg, Maryland 20889-6102, United States,
| | - Lorenzo Guio
- Department
of Material Science and Engineering, University
of Washington, Box 352120, Seattle, Washington 98195-2120, United States
| | - Sage Scheiwiller
- Department
of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195-1750, United States
| | - Viktoria Pakhnyuk
- Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Christine Luscombe
- Department
of Material Science and Engineering, University
of Washington, Box 352120, Seattle, Washington 98195-2120, United States,Department
of Chemistry, University of Washington, Box 351700, Seattle, Washington 98195-1700, United States
| | - Lilo D. Pozzo
- Department
of Chemical Engineering, University of Washington, Box 351750, Seattle, Washington 98195-1750, United States,
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Balacescu L, Brandl G, Radulescu A. Separation of the inelastic and elastic scattering in time-of-flight mode on the pinhole small-angle neutron scattering diffractometer K-WS-2. J Appl Crystallogr 2021; 54:1217-1224. [PMID: 34429724 PMCID: PMC8366428 DOI: 10.1107/s1600576721006610] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 06/24/2021] [Indexed: 02/19/2023] Open
Abstract
To study and control the incoherent inelastic background in small-angle neutron scattering, which makes a significant contribution to the detected scattering from hydrocarbon systems, the KWS-2 small-angle neutron scattering diffractometer operated by the Jülich Centre for Neutron Science (JCNS) at Heinz-Maier Leibnitz Zentrum (MLZ), Garching, Germany, was equipped with a secondary single-disc chopper that is placed in front of the sample stage. This makes it possible to record in time-of-flight mode the scattered neutrons in the high-Q regime of the instrument (i.e. short incoming wavelengths and detection distances) and to discard the inelastic component from the measured data. Examples of measurements on different materials routinely used as standard samples, sample containers and solvents in the experiments at KWS-2 are presented. When only the elastic region of the spectrum is used in the data-reduction procedure, a decrease of up to two times in the incoherent background of the experimentally measured scattering cross section may be obtained. The proof of principle is demonstrated on a solution of bovine serum albumin in D2O.
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Affiliation(s)
- Livia Balacescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
- Physikalisches Institut (IA), Rheinisch-Westfälische Technische Hochschule (RWTH), Otto-Blumenthal Strasse, Aachen, 52074, Germany
| | - Georg Brandl
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
| | - Aurel Radulescu
- Jülich Centre for Neutron Science (JCNS) at Heinz Maier-Leibnitz Zentrum (MLZ), Forschungszentrum Jülich GmbH, Lichtenbergstrasse 1, Garching, 85747, Germany
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Foglia F, Lyonnard S, Sakai VG, Berrod Q, Zanotti JM, Gebel G, Clancy AJ, McMillan PF. Progress in neutron techniques: towards improved polymer electrolyte membranes for energy devices. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2021; 33:264005. [PMID: 33906172 DOI: 10.1088/1361-648x/abfc10] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Accepted: 04/27/2021] [Indexed: 06/12/2023]
Abstract
Design and implementation of advanced membrane formulations for selective transport of ions and molecular species are critical for creating the next generations of fuel cells and separation devices. It is necessary to understand the detailed transport mechanisms over time- and length-scales relevant to the device operation, both in laboratory models and in working systems under realistic operational conditions. Neutron scattering techniques including quasi-elastic neutron scattering, reflectivity and imaging are implemented at beamline stations at reactor and spallation source facilities worldwide. With the advent of new and improved instrument design, detector methodology, source characteristics and data analysis protocols, these neutron scattering techniques are emerging as a primary tool for research to design, evaluate and implement advanced membrane technologies for fuel cell and separation devices. Here we describe these techniques and their development and implementation at the ILL reactor source (Institut Laue-Langevin, Grenoble, France) and ISIS Neutron and Muon Spallation source (Harwell Science and Technology Campus, UK) as examples. We also mention similar developments under way at other facilities worldwide, and describe approaches such as combining optical with neutron Raman scattering and x-ray absorption with neutron imaging and tomography, and carrying out such experiments in specialised fuel cells designed to mimic as closely possible actualoperandoconditions. These experiments and research projects will play a key role in enabling and testing new membrane formulations for efficient and sustainable energy production/conversion and separations technologies.
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Affiliation(s)
- Fabrizia Foglia
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Sandrine Lyonnard
- University Grenoble Alpes, CNRS, CEA, IRIG-SyMMES, 38000 Grenoble, France
| | - Victoria García Sakai
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Chilton OX11 0QX, United Kingdom
| | - Quentin Berrod
- University Grenoble Alpes, CNRS, CEA, IRIG-SyMMES, 38000 Grenoble, France
| | - Jean-Marc Zanotti
- Laboratoire Léon Brillouin (CEA-CNRS), Université Paris-Saclay, CEA Saclay, 91191 Gif-sur-Yvette Cedex, France
| | - Gérard Gebel
- University Grenoble Alpes, CEA LITEN, 38000 Grenoble, France
| | - Adam J Clancy
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, United Kingdom
| | - Paul F McMillan
- Department of Chemistry, Christopher Ingold Laboratory, University College London, 20 Gordon St., London WC1H 0AJ, United Kingdom
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Khairy Y, Alvarez F, Arbe A, Colmenero J. Disentangling Self-Atomic Motions in Polyisobutylene by Molecular Dynamics Simulations. Polymers (Basel) 2021; 13:polym13040670. [PMID: 33672368 PMCID: PMC7927061 DOI: 10.3390/polym13040670] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Revised: 02/08/2021] [Accepted: 02/17/2021] [Indexed: 01/16/2023] Open
Abstract
We present fully atomistic molecular dynamics simulations on polyisobutylene (PIB) in a wide temperature range above the glass transition. The cell is validated by direct comparison of magnitudes computed from the simulation and measured by neutron scattering on protonated samples reported in previous works. Once the reliability of the simulation is assured, we exploit the information in the atomic trajectories to characterize the dynamics of the different kinds of atoms in PIB. All of them, including main-chain carbons, show a crossover from Gaussian to non-Gaussian behavior in the intermediate scattering function that can be described in terms of the anomalous jump diffusion model. The full characterization of the methyl-group hydrogen motions requires accounting for rotational motions. We show that the usually assumed statistically independence of rotational and segmental motions fails in this case. We apply the rotational rate distribution model to correlation functions calculated for the relative positions of methyl-group hydrogens with respect to the carbon atom at which they are linked. The contributions to the vibrational density of states are also discussed. We conclude that methyl-group rotations are coupled with the main-chain dynamics. Finally, we revise in the light of the simulations the hypothesis and conclusions made in previously reported neutron scattering investigations on protonated samples trying to address the origin of the dielectric β-process.
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Affiliation(s)
- Yasmin Khairy
- Physics Department, Faculty of Science, Zagazig University, Zagazig 44519, Egypt;
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
| | - Fernando Alvarez
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
| | - Arantxa Arbe
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
| | - Juan Colmenero
- Centro de Física de Materiales (CSIC, UPV/EHU), Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain; (F.A.); (A.A.)
- Materials Physics Center MPC, Paseo Manuel de Lardizabal 5, E-20018 San Sebastián, Spain
- Departamento de Polímeros y Materiales Avanzados: Física, Química y Tecnología (UPV/EHU), Apartado 1072, E-20080 San Sebastián, Spain
- Donostia International Physics Center (DIPC), Paseo Manuel de Lardizabal 4, E-20018 San Sebastián, Spain
- Correspondence:
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