Article
Physics, Multidisciplinary
Entao Yang, Robert A. Riggleman
Summary: External stress can greatly enhance the molecular mobility of amorphous solids, and this phenomenon can be explained by the Eyring model. In this study, we analyzed constant-stress molecular dynamics simulations and proposed a structure-dependent Eyring model that connects activation volume with a machine-learned field called softness. Our findings reveal that stress has a heterogeneous effect on mobility, which is determined by the local structure as described by softness.
PHYSICAL REVIEW LETTERS
(2022)
Article
Materials Science, Multidisciplinary
S. Guchhait, D. V. Ambika, Qing-Ping Ding, M. Uhlarz, Y. Furukawa, A. A. Tsirlin, R. Nath
Summary: The structural and magnetic properties of a new spin-1/2 antiferromagnet NaZnVOPO4(HPO4) were studied using various methods, revealing significant magnetic behaviors and characteristics. The findings suggest that this compound exhibits unique features that deviate from conventional models.
Article
Physics, Multidisciplinary
Daniel L. Baker, Matthew Reynolds, Robin Masurel, Peter D. Olmsted, Johan Mattsson
Summary: The study investigates how the glass transition temperature T-g varies with molecular weight M for different polymer chemistries and chain flexibilities. The results show that T-g(M) is controlled by the average mass or volume per conformational degree of freedom and that a local molecular relaxation affects the larger-scale cooperative alpha relaxation responsible for T-g. The study suggests that dynamic facilitation can explain the observations, including logarithmic T-g(M) dependences. This study provides a new understanding of molecular relaxations and the glass transition in polymers, which can contribute to predictive design of polymers based on monomer-scale metrics.
Article
Multidisciplinary Sciences
Florian Spieckermann, Daniel Sopu, Viktor Soprunyuk, Michael B. Kerber, Jozef Bednarcik, Alexander Schokel, Amir Rezvan, Sergey Ketov, Baran Sarac, Erhard Schafler, Juergen Eckert
Summary: In-situ X-ray diffraction is used to study structural rearrangements during annealing processes in Cu44Zr-44Al8Hf2Co2 bulk metallic glass. The deformation-induced rejuvenation reveals a structural footprint that can be correlated to calorimetric signals, showing characteristics of a first-order transition for the beta-transition. Dynamic mechanical analysis data indicates that non-reversible structural rearrangements are preferentially activated during the beta-transition, while reversible deformations dominate the low-temperature alpha-transition with second-order characteristics.
NATURE COMMUNICATIONS
(2022)
Article
Chemistry, Multidisciplinary
Chenxi Zhai, Shangchao Lin, Mingchao Wang, Huanhuan Zhou, Eugenia Stanisauskis, Zhuangli Cai, Jingjie Yeo, William Oates
Summary: The study utilized molecular dynamics simulations to understand the limiting factors for optomechanical conversion in photostrictive polymers. It found that conformational freedom has a significant impact on optomechanical efficiency, with materials possessing larger conformational freedom exhibiting over 10 times higher efficiency than existing experiments.
ADVANCED FUNCTIONAL MATERIALS
(2021)
Article
Engineering, Chemical
Sidath Wijesinghe, Dvora Perahia, Ting Ge, K. Michael Salerno, Gary S. Grest
Summary: The stress relaxation of branched polymers, especially the impact of branch length compared to the entanglement length of linear polymer, plays a crucial role in viscosity modification. Shorter branch lengths relax within the entanglement time, affecting chain mobility and stress relaxation by increasing tube diameter and friction coefficient, essentially acting as a solvent in the system.
Article
Physics, Multidisciplinary
Panagiotis Kardasis, Nikolaos Kalafatakis, Mario Gauthier, Dimitris Vlassopoulos, George Floudas
Summary: Multiarm stars of 1,4-polybutadiene with very high branching functionality exhibit distinct layers of segmental mobility, with outer, intermediate, and near-core segments displaying a Vogel-Fulcher-Tammann temperature dependence. The corresponding glass temperatures increase with the square root of the branching functionality, suggesting potential implications for theoretical treatments in hybrid nanoparticles.
PHYSICAL REVIEW LETTERS
(2021)
Article
Mathematics
Viktor Vegh, Shahrzad Moinian, Qianqian Yang, David C. Reutens
Summary: Mathematical models play a crucial role in linking tissue microstructure with MRI signals. The Bloch equations describe spin and relaxation in a magnetic field, while the time-fractional order Bloch equations provide a better fit for brain MRI signals. Time-fractional models offer solutions in the form of Mittag-Leffler functions, which have been proven useful for describing relaxation in complex materials.
Article
Chemistry, Physical
Lukasz Kolek, Malgorzata Jasiurkowska-Delaporte, Ewa Juszynska-Galazka
Summary: The non-isothermal cold crystallization process of 3F5BFBiHex from the antiferroelectric SmCA* phase was studied using DSC and BDS experiments. DSC studies showed the complexity of the crystallization process, while BDS method described the behaviors of molecular I-process and collective anti-phase Phason relaxation processes. Energy barriers obtained from different models differed, but were close in DSC and BDS methods.
JOURNAL OF MOLECULAR LIQUIDS
(2021)
Article
Polymer Science
Jessica Mangialetto, Niko van den Brande, Bruno Van Mele, Michael Wuebbenhorst
Summary: This study systematically investigated the molecular dynamics of the reversible network 4F230-2M230 using dielectric relaxation spectroscopy. The cooperative segmental dynamics in the network were studied through the dielectric alpha-relaxation. The study showed an excellent agreement between the dynamic T(g) derived from relaxation times and the thermal T(g) derived from dielectric spectra, confirming the equivalence of both quantities in glass-forming materials.
Article
Polymer Science
Nadezhda N. Sheveleva, Valeriy V. Bezrodnyi, Sofia E. Mikhtaniuk, Oleg Shavykin, Igor M. Neelov, Irina I. Tarasenko, Mikhail A. Vovk, Mariya E. Mikhailova, Anastasia Penkova, Denis A. Markelov
Summary: This study investigated the orientational mobility of collapsed and swollen dendrimers using NMR relaxation experiments and atomistic simulations, revealing that volume interactions suppress internal local mobility while reorientation occurs due to the rotation of the dendrimer as a whole. These findings suggest that considering segmental mobility is crucial for interpreting the mobility of CH2 groups observed in NMR experiments.
Article
Biochemistry & Molecular Biology
Khairul Anwar Ishak, Thamil Selvi Velayutham, Mohamad Suffian Mohamad Annuar, A. Azeez Olayiwola Sirajudeen
Summary: Dielectric spectroscopy was used to study relaxation phenomena in PHAs, revealing the effects of molecular structure and temperature on dielectric response. Primary α-relaxation signals were observed at glass transition temperature, while secondary β- and γ-relaxations were detected at low temperatures. Comparison and discussion of dielectric properties of representative PHA samples were conducted.
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
(2021)
Article
Radiology, Nuclear Medicine & Medical Imaging
Teresa Gerhalter, Martijn Cloos, Anna M. Chen, Seena Dehkharghani, Rosemary Peralta, James S. Babb, Alejandro Zarate, Tamara Bushnik, Jonathan M. Silver, Brian S. Im, Stephen Wall, Steven Baete, Guillaume Madelin, Ivan I. Kirov
Summary: The relaxation properties derived from MRF, particularly T-1, showed higher utility for predicting outcomes 3 months after mild traumatic brain injury (mTBI) compared to T-2, fractional anisotropy (FA), and apparent diffusion coefficient (ADC). High T-1 at baseline and serially increasing T-1 were strong indicators of non-recovery at 3 months post-injury.
EUROPEAN RADIOLOGY
(2022)
Article
Polymer Science
Wenduo Chen, Shaonan Wei
Summary: This study utilized Langevin Dynamics Simulations to investigate the compression and relaxation processes of confined ring polymers in a nanochannel. The findings revealed that ring polymers exhibit complex deformations under different levels of confinement, with weakly confined polymers compressed into condensed blobs and strongly confined polymers undergoing deformations from double helix to collapsed states. During relaxation, weakly confined rings return to their initial states, while strongly confined rings extend from compacted states to randomly folded states due to interpenetrated and self-entangled structures formed during compression.
Article
Computer Science, Information Systems
Shihab Hamad Khaleefah, Salama A. Mostafa, Aida Mustapha, Mohammad Faidzul Nasrudin
Summary: This article introduces an Automated Paper Fingerprinting (APF) method that uses a combination of Gabor Filters (GF) and Uniform Local Binary Patterns (ULBP) called the GFULBP operator to improve texture classification accuracy. Test results show that GFULBP outperforms ULBP alone by 30.68% in certain conditions. The integration of Gabor filters and ULBP significantly enhances feature extraction quality and fingerprinting accuracy.
JOURNAL OF KING SAUD UNIVERSITY-COMPUTER AND INFORMATION SCIENCES
(2021)
Article
Chemistry, Medicinal
Rachel R. Ford, Peter H. Gilbert, Richard Gillilan, Qingqiu Huang, Roisin Donnelly, Ken K. Qian, David P. Allen, Norman J. Wagner, Yun Liu
Summary: A systematic study using small-angle x-ray scattering (SAXS) was conducted to investigate the phase behavior and morphological causes of aggregation of poloxamer 188 (P188) in the presence of phenol and benzyl alcohol. The results showed that P188 remained as unimers at low phenol concentrations, formed micelles at moderate phenol concentrations due to the interaction with phenol, and exhibited turbidity and phase separation at high phenol concentrations. The effect of benzyl alcohol on the phase behavior was also investigated.
JOURNAL OF PHARMACEUTICAL SCIENCES
(2023)
Article
Polymer Science
Kun Song, Dong Liu, Lin-Feng Wu, Zhe Wang
Summary: The growth of lamellar crystals in stretched crosslinked high-density polyethylene samples was investigated using in situ small-angle X-ray scattering and wide-angle X-ray diffraction. The growth process was found to undergo three stages: interface-controlled, diffusion-controlled, and crystal perfection stages through the Ostwald ripening mechanism. The transitions between stages were affected by chain diffusion, chain consumption, and depletion of crystallizable chains.
Article
Polymer Science
Huarui Wu, Dejia Kong, Lin-Feng Wu, Yubin Ke, Mark Robertson, Lilin He, Zhe Wang
Summary: We experimentally investigated the structure, dynamics, and linear rheology of dendrimer solutions as a model system for Gaussian-core fluids and ultrasoft colloids. We compared the results with a coarse-grained approach. Our findings revealed unexpected behaviors, such as plasticine-like particle packing in the overpacked regime and counterintuitive softening of interparticle interaction under densification. These observations highlight the crucial role of intraparticle complexity in the structure and dynamics of ultrasoft colloids.
Article
Nanoscience & Nanotechnology
Zongyu Wang, Bishnu P. Thapaliya, Ilja Popovs, Yangyang Wang, Tao Wang, Jihua Chen, Mark A. Arnould, Shannon M. Mahurin, Sheng Dai
Summary: The construction of solid electrolytes coated with multiple layers of polyanions and polycations using layer-by-layer assembly method demonstrates good ionic conductivity and mechanical robustness, making them valuable for electrochemical devices and high-voltage battery applications.
ACS APPLIED MATERIALS & INTERFACES
(2023)
Article
Biochemistry & Molecular Biology
Meng Zhang, Yun Liu, Xiaobing Zuo, Shuo Qian, Sai Venkatesh Pingali, Richard E. Gillilan, Qingqiu Huang, Donghui Zhang
Summary: This study investigates the influence of positionally controlled ionization sites on the micellization and micellar structure of copolymers. The introduction of an ionizable site at the hydrophobic terminus promotes the formation of equilibrium micellar structures in aqueous solutions. The presence of oppositely charged ionizable sites along the polymer chains allows for the electrostatic modulation of polymer association in a broad pH range.
Article
Chemistry, Physical
Jan-Michael Carrillo, Yangyang Wang, Rajeev Kumar, Bobby G. Sumpter
Summary: This study investigates the behavior of charged polyelectrolytes in semidilute solutions using explicit-solvent coarse-grained molecular dynamics simulations. The results highlight the importance of explicit-solvent effects in understanding polyelectrolyte solution behavior, particularly in semidilute solutions.
EUROPEAN PHYSICAL JOURNAL E
(2023)
Article
Chemistry, Physical
Zhiqiang Shen, Jan-Michael Y. Carrillo, Bobby G. Sumpter, Yangyang Wang
Summary: The collective density-density and hydrostatic pressure-pressure correlations of glass-forming liquids were investigated using molecular dynamics simulations. It was found that below the Arrhenius temperature, there is a slow nonhydrodynamic collective dynamics that is closely related to the local structural dynamics. This result highlights the importance of understanding the dynamic crossover phenomenon.
JOURNAL OF CHEMICAL PHYSICS
(2023)
Article
Chemistry, Physical
Kiet G. Pham, Benjamin R. Thompson, Tingting Wang, Shayak Samaddar, Ken K. Qian, Yun Liu, Norman J. Wagner
Summary: By measuring the interfacial viscoelasticity and surface pressure of mAbs at the air-water interface, we can predict their long-term stability, which is crucial in the pharmaceutical industry.
JOURNAL OF PHYSICAL CHEMISTRY B
(2023)
Article
Polymer Science
Guan-Rong Huang, Chi-Huan Tung, Lionel Porcar, Yangyang Wang, Yuya Shinohara, Changwoo Do, Wei-Ren Chen
Summary: This paper outlines a strategy for determining the size polydispersity of systems using small angle coherent scattering. By employing the method of moment expansion, the various central moments representing the average particle size, variance of particle size, and skewness of size distribution function (SDF) can be extracted from spectral analysis without bias. The effectiveness of this approach is demonstrated through numerical benchmarking and experimental validation using small-angle neutron scattering data obtained from L64 Pluronic micelles.
Article
Chemistry, Multidisciplinary
Karina Abitaev, Petia Atanasova, Joachim Bill, Natalie Preisig, Ivan Kuzmenko, Jan Ilavsky, Yun Liu, Thomas Sottmann
Summary: ZnO inverse opals are valuable photonic and catalysis support materials that combine the properties of ZnO semiconductor with the high surface area of the open-porous framework. The formation and growth of ZnO nanoparticles in a precursor solution containing PVP was studied using in situ USAXS/SAXS. The kinetics of nucleation and growth process were analyzed using the Finke-Watzky model.
Article
Chemistry, Multidisciplinary
Christopher N. Lam, Lilin He, Changwoo Do, Wei-Ren Chen, Weiyu Wang, Kunlun Hong, Yangyang Wang
Summary: The Zimm plot has been extended to anisotropic materials by analyzing the reciprocal scattering intensity from deformed polymers. In the small-angle limit, a tensorial extension of the Guinier law is found to describe the deformation of polymers. In the high-Q limit, the spherical harmonic expansion technique allows for direct model-independent analysis of spatially dependent molecular deformation.
JOURNAL OF APPLIED CRYSTALLOGRAPHY
(2023)
Article
Medicine, Research & Experimental
RoisinB. Donnelly, Sai Venkatesh Pingali, Luke Heroux, Robert G. Brinson, Norman J. Wagner, Yun Liu
Summary: Understanding protein dynamics and conformational stability is important in biopharmaceutical research. Hydrogen-deuterium exchange (HDX) is a quantitative method used to study these properties. This study explores the use of small-angle neutron scattering (SANS) as a novel HDX method, which allows for the evaluation of subtle changes in protein structure and the impact of electrolytes on protein stability. HDX-SANS is shown to be a sensitive and noninvasive technique for quantifying protein dynamics and providing new information about protein conformational fluctuations.
MOLECULAR PHARMACEUTICS
(2023)
Article
Multidisciplinary Sciences
Zening Liu, Jong K. Keum, Tianyu Li, Jihua Chen, Kunlun Hong, Yangyang Wang, Bobby G. Sumpter, Rigoberto Advincula, Rajeev Kumar
Summary: In this study, the conformational hypotheses of polyzwitterions (PZs) in dilute aqueous solutions are tested by investigating the effects of added salt on the gyration and hydrodynamic radii of poly(sulfobetaine methacrylate). The results reveal the importance of salt in affecting the net charge and conformations of PZs, with the observations of antipolyelectrolyte and polyelectrolyte effects.
Article
Chemistry, Physical
Ruikun Sun, Jie Yang, Shalin Patil, Yun Liu, Xiaobing Zuo, Andre Lee, Wei Yang, Yangyang Wang, Shiwang Cheng
Summary: The relaxation dynamics of PS/silica nanocomposites were studied, and it was found that nanoparticle aggregation enhances the mechanical properties, while nanoparticle loading accelerates structural anisotropy relaxation.
Article
Physics, Fluids & Plasmas
Zhiqiang Shen, Jan-Michael Y. Carrillo, Bobby G. Sumpter, Yangyang Wang
Summary: The analysis of space-time density-density correlation functions of polymers is complicated by the intrachain averaging of distinct self-dynamics of different segments. This study shows that the averaging process conceals critical dynamical information and contributes to the observed nonGaussian dynamics. A more nuanced approach to polymer self-dynamics is required.