443 results match your criteria: "Jülich Centre for Neutron Science JCNS[Affiliation]"

This study investigates lead-free organic-inorganic hybrids (CNH)[BiCl] () and (CNH)[BiBr] (), focusing on their structural, dielectric, ferroelectric, and optical properties. Both compounds exhibit paraelectric () to ferroelectric () phase transitions (PTs) at 230/233 K and 228/229 K, respectively, transitioning from orthorhombic () to monoclinic (2) phases, with distorted [BiX] octahedra forming 1D chains. Quasielastic neutron scattering and solid-state H NMR studies reveal the localized motion of azetidinium cations.

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This work investigates the conversion of bicelles into larger sheets or closed vesicles upon dilution and temperature increase for a system composed of the phospholipid 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and the saponin aescin. Due to its peculiar amphiphilic character, aescin is able to decompose DMPC bilayers into smaller, rim-stabilized bicelles. Aspects of the transition process are analyzed in an aescin content- and temperature-dependent manner by photon correlation spectroscopy (PCS), turbidimetry and small-angle neutron scattering (SANS).

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A confined bicontinuous CE-DO--octane microemulsion is studied using neutron spin echo spectroscopy (NSE). Controlled pore glasses serve as confining matrices with pore diameters ranging from 24 to 112 nm. Firstly, the microemulsion in bulk is investigated by NSE and dynamic light scattering, which allows the determination of the unperturbed collective dynamics as well as the observation of the undulation of the surfactant film.

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Making Sticky-Slippery Switchable Fluorogels Through Self-Adaptive Bicontinuous Phase Separation.

Adv Mater

November 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering & Center for Advanced Low-dimension Materials, Donghua University, 2999 North Renmin Road, Shanghai, 201620, China.

Developing gel materials with tunable frictional properties is crucial for applications in soft robotics, anti-fouling, and joint protection. However, achieving reversible switching between extreme sticky and slippery states remains a formidable challenge due to the opposing requirements for energy dissipation on gel surfaces. Herein, a self-adaptive bicontinuous fluorogel is introduced that decouples lubrication and adhesion at varying temperatures.

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PNIPAM Mesoglobules in Dependence on Pressure.

Langmuir

October 2024

TUM School of Natural Sciences, Physics Department, Soft Matter Physics Group, Technical University of Munich, James-Franck-Str. 1, Garching 85748, Germany.

Poly(-isopropylacrylamide) (PNIPAM) in aqueous solution forms mesoglobules above its cloud point temperature . While these are small and compact at atmospheric pressure, they are large and water-rich at high pressure. To identify the transition between these states, we employed optical microscopy and carried out isothermal pressure scans.

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Superparamagnetic iron oxide nanoparticles (SPIONs) are a promising tool for biomedical applications, including drug delivery, imaging, and magnetic hyperthermia. However, their tendency to agglomerate limits their performance efficiency. To overcome this limitation, a coating can be applied during or after synthesis.

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Polymer solid-state electrolytes offer great promise for battery materials with high energy density, mechanical stability, and improved safety. However, their low ion conductivities have so far limited their potential applications. Here, it is shown for poly(ethylene oxide) block copolymers that the super-stoichiometric addition of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) as lithium salt leads to the formation of a crystalline PEO block copolymer phase with exceptionally high ion conductivities and low activation energies.

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Planar XY magnetic glass state in the GdScNbOpyrochlore.

J Phys Condens Matter

September 2024

Department of Chemistry, University of Manitoba, Winnipeg R3T 2N2, Canada.

Here a spin glass system with emergent planar ordered spin clusters is investigated. The mixed B-site pyrochlore GdScNbOhas been synthesized and characterized through a variety of techniques, including x-ray diffraction, magnetic susceptibility, muon spin relaxation, heat capacity and neutron scattering. Despite a Curie-Weiss temperature of -3.

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Low-Hysteresis and Tough Ionogels via Low-Energy-Dissipating Cross-Linking.

Adv Mater

November 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, National Engineering Research Center for Dyeing and Finishing of Textiles, Center for Advanced Low-dimension Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China.

Low-hysteresis merits can help polymeric gel materials survive from consecutive loading cycles and promote life span in many burgeoning areas. However, it is a big challenge to design low-hysteresis and tough polymeric gel materials, especially for ionogels. This can be attributed to the fact that higher viscosities of ionic liquids (ILs) would increase chain friction of polymeric gels and eventually dissipate large amounts of energy under deformation.

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Spin dynamics of the E particles.

Sci Bull (Beijing)

October 2024

Helmholtz-Zentrum Berlin für Materialien und Energie GmbH, Berlin D-14109, Germany; Institut für Festkö rperphysik, Technische Universität Berlin, Berlin D-10623, Germany. Electronic address:

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Manipulating the hydrophilic / hydrophobic balance in novel cationic surfactants by ethoxylation: The impact on adsorption and self-assembly.

J Colloid Interface Sci

November 2024

ISIS Facility, Science and Technology Facilities Council, Rutherford Appleton Laboratory, Chilton, Didcot, OXON, UK.

Hypothesis: Cationic surfactants have a wide range of applications, often associated with their affinity for a range of solid surfaces and their anti-microbial properties. Manipulating their adsorption and self-assembly properties is key to most applications, and this is commonly achieved through surfactant mixtures or manipulating their headgroup or alkyl chain structure. Achieving this through adjustments to their headgroup structure is less common in cationic surfactants than in anionic surfactants.

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Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH) and its demethylated counterpart PIM-EA-TB(H), which have high Brunauer-Emmett-Teller surface area values of 1030 m g and 836 m g, respectively.

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We present a neutron spin echo (NSE) investigation to examine the impact of macromolecular crowding on the dynamics of single-chain nanoparticles (SCNPs), serving as synthetic models for biomacromolecules with flexibility and internal degrees of freedom, such as intrinsically disordered proteins (IDPs). In particular, we studied the dynamics of a medium-size poly(methyl methacrylate) (PMMA)-based SCNP (33 kDa) in solutions with low- (10 kDa) and high- (100 kDa) molecular weight analogous deuterated PMMA linear crowders. The dynamic structure factors of the SCNPs in dilute solution show certain degrees of freedom, yet the analysis in terms of the Zimm model reveals high internal friction that effectively stiffens the chain-a phenomenon also observed for IDPs.

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Crowding effects significantly influence the phase behavior and the structural and dynamic properties of the concentrated protein mixtures present in the cytoplasm of cells or in the blood serum. This poses enormous difficulties for our theoretical understanding and our ability to predict the behavior of these systems. While the use of course grained colloid-inspired models allows us to reproduce the key physical solution properties of concentrated monodisperse solutions of individual proteins, we lack corresponding theories for complex polydisperse mixtures.

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Charge Regulation Triggers Condensation of Short Oligopeptides to Polyelectrolytes.

JACS Au

May 2024

Department of Physical and Macromolecular Chemistry, Faculty of Science, Charles University, Hlavova 8, Prague 2 128 40, Czech Republic.

Electrostatic interactions between charged macromolecules are ubiquitous in biological systems, and they are important also in materials design. Attraction between oppositely charged molecules is often interpreted as if the molecules had a fixed charge, which is not affected by their interaction. Less commonly, charge regulation is invoked to interpret such interactions, i.

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The phase behavior of the liquid CD below and above the critical point was investigated using small-angle neutron scattering (SANS) in temperature and pressure ranges from 10 to 45 °C and 20 to 126 bar, respectively. The scattering of thermal fluctuations of the molecular density was determined and thus the gas-liquid and Widom lines. At the same time, we observed additional scattering of droplets of more densely packed CD molecules above the gas-liquid line and in the supercritical fluid regime from just below the critical point for all temperatures at about Δ = 10 bar above the Widom line.

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Hydrogen Bonding Competition Mediated Phase Separation with Abnormal Moisture-Induced Stiffness Boosting.

Small

September 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China.

Moisture usually deteriorates polymers' mechanical performance owing to its plasticizing effect, causing side effects in their practical load-bearing applications. Herein, a simple binary ionogel consisting of an amphiphilic polymer network and a hydrophobic ionic liquid (IL) is developed with remarkable stiffening effect after moisture absorption, demonstrating a complete contrast to water-induced softening effect of most polymer materials. Such a moisture-induced stiffening behavior is induced by phase separation after hydration of this binary ionogel.

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Intrinsically disordered late embryogenesis abundant (LEA) proteins play a central role in the tolerance of plants and other organisms to dehydration brought upon, for example, by freezing temperatures, high salt concentration, drought or desiccation, and many LEA proteins have been found to stabilize dehydration-sensitive cellular structures. Their conformational ensembles are highly sensitive to the environment, allowing them to undergo conformational changes and adopt ordered secondary and quaternary structures and to participate in formation of membraneless organelles. In an interdisciplinary approach, we discovered how the functional diversity of the Arabidopsis thaliana LEA protein COR15A found in vitro is encoded in its structural repertoire, with the stabilization of membranes being achieved at the level of secondary structure and the stabilization of enzymes accomplished by the formation of oligomeric complexes.

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A Solid-Liquid Bicontinuous Fiber with Strain-Insensitive Ionic Conduction.

Adv Mater

June 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering & Center for Advanced Low-dimension Materials, Donghua University, Shanghai, 201620, China.

Stretchable ionic conductors are crucial for enabling advanced iontronic devices to operate under diverse deformation conditions. However, when employed as interconnects, existing ionic conductors struggle to maintain stable ionic conduction under strain, hindering high-fidelity signal transmission. Here, it is shown that strain-insensitive ionic conduction can be achieved by creating a solid-liquid bicontinuous microstructure.

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The co-assembly of polyelectrolytes (PE) with proteins offers a promising approach for designing complex structures with customizable morphologies, charge distribution, and stability for targeted cargo delivery. However, the complexity of protein structure limits our ability to predict the properties of the formed nanoparticles, and our goal is to identify the key triggers of the morphological transition in protein/PE complexes and evaluate their ability to encapsulate multivalent ionic drugs. A positively charged PE can assemble with a protein at pH above isoelectric point due to the electrostatic attraction and disassemble at pH below isoelectric point due to the repulsion.

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Hydrogels with Differentiated Hydrogen-Bonding Networks for Bioinspired Stress Response.

Angew Chem Int Ed Engl

May 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering, Donghua University, Shanghai, 201620, China.

Stress response, an intricate and autonomously coordinated reaction in living organisms, holds a reversible, multi-path, and multi-state nature. However, existing stimuli-responsive materials often exhibit single-step and monotonous reactions due to the limited integration of structural components. Inspired by the cooperative interplay of extensor and flexor cells within Mimosa's pulvini, we present a hydrogel with differentiated hydrogen-bonding (H-bonding) networks designed to enable the biological stress response.

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Amorphous-Like Ultralow Thermal Transport in Crystalline Argyrodite CuPS.

Adv Sci (Weinh)

June 2024

CRISMAT, CNRS, ENSICAEN, UNICAEN, Normandie Univ, Caen, 14000, France.

Due to their amorphous-like ultralow lattice thermal conductivity both below and above the superionic phase transition, crystalline Cu- and Ag-based superionic argyrodites have garnered widespread attention as promising thermoelectric materials. However, despite their intriguing properties, quantifying their lattice thermal conductivities and a comprehensive understanding of the microscopic dynamics that drive these extraordinary properties are still lacking. Here, an integrated experimental and theoretical approach is adopted to reveal the presence of Cu-dominated low-energy optical phonons in the Cu-based argyrodite CuPS.

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Article Synopsis
  • Magnetite nanoparticles are promising anode materials for lithium-ion batteries due to their high potential energy storage, but the lithiation process is not fully understood.
  • The study examines 70 nm cubic magnetite nanoparticles with lithiation levels of 0, 0.5, 1, and 1.5, revealing a structural transformation from spinel to rock salt phase at lithium concentrations between 0.5 and 1.
  • Magnetization measurements indicate the formation of antiferromagnetic LiFeO and highlight an exchange bias in the hysteresis loops, suggesting complex magnetic properties tied to the lithiation process.
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Bioprinting has evolved into a thriving technology for the fabrication of cell-laden scaffolds. Bioinks are the most critical component for bioprinting. Recently, microgels have been introduced as a very promising bioink, enabling cell protection and the control of the cellular microenvironment.

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Entropy-Driven Design of Highly Impact-Stiffening Supramolecular Polymer Networks with Salt-Bridge Hydrogen Bonds.

J Am Chem Soc

March 2024

State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Chemistry and Chemical Engineering & Center for Advanced Low-dimension Materials, Donghua University, Shanghai 201620, China.

Impact-stiffening materials that undergo a strain rate-induced soft-to-rigid transition hold great promise as soft armors in the protection of the human body and equipment. However, current impact-stiffening materials, such as polyborosiloxanes and shear-thickening fluids, often exhibit a limited impact-stiffening response. Herein, we propose a design strategy for fabricating highly impact-stiffening supramolecular polymer networks by leveraging high-entropy-penalty physical interactions.

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