0000000000535173

AUTHOR

Bernhard Frick

showing 3 related works from this author

QENS investigation of filled rubbers

2002

The polymer segmental dynamics is investigated in a series of silica-filled rubbers. The presence of inert fillers in polymers greatly affects the mechanical and physical performance of the final materials. For example, silica has been proposed as a reinforcing agent of elastomers in tire production. Results from quasielastic neutron scattering and Dynamic Mechanical Thermal Analysis (DMTA) measurements are presented on styrene–ran-butadiene rubber filled with silica. A clear indication is obtained of the existence of a bimodal dynamics, which can be rationalized in terms of the relaxation of bulk rubber and the much slower relaxation of the rubber adsorbed on the filler surface.

chemistry.chemical_classificationMaterials scienceGeneral ChemistryDynamic mechanical analysisPolymerengineering.materialElastomerNatural rubberchemistryvisual_artFiller (materials)Quasielastic neutron scatteringvisual_art.visual_art_mediumengineeringRelaxation (physics)General Materials ScienceComposite materialThermal analysisApplied Physics A: Materials Science & Processing
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Segmental dynamics in polymer electrolytes

2002

Polymer dynamics in poly(ethylene oxide) (PEO)–salt mixtures is investigated by means of quasi-elastic neutron scattering (QENS). In a previous study, we reported QENS data from the NEAT spectrometer (BENSC) that evidenced, for the first time, a dynamic heterogeneity in PEO–salt mixtures induced by salt addition. This finding is supported by molecular dynamics (MD) simulations carried out by Borodin et al. In agreement with MD simulations, our QENS data revealed two distinct processes: a fast motion corresponding to the bulk polymer and a slower relaxation, which we attribute to formation of PEO–cation complexes. In this paper we present new QENS data from the high-resolution spectrometer I…

chemistry.chemical_classificationMaterials scienceEthylene oxideSpectrometerPolymer electrolytesDynamics (mechanics)Relaxation (NMR)General ChemistryPolymerNeutron scatteringCrystallographyMolecular dynamicschemistry.chemical_compoundchemistryChemical physicsGeneral Materials ScienceApplied Physics A: Materials Science & Processing
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Neutron Scattering Reveals Enhanced Protein Dynamics in Concanavalin A Amyloid Fibrils

2012

Protein aggregation is one of the most challenging topics in life sciences, and it is implicated in several human pathologies. The nature and the role of toxic species is highly debated, with amyloid fibrils being among the most relevant species for their peculiar structural and functional properties. Protein dynamics and in particular the ability to fluctuate through a large number of conformational substates are closely related to protein function. This Letter focuses on amyloid fibril dynamics, and, to our knowledge, it is the first neutron scattering study on a protein (Concanavalin A) isolated in its fibril state. Our results reveal enhanced atomic fluctuations in amyloid fibrils and i…

Protein functionbiologyChemistryProtein dynamicsmean square displacementsA proteinatomic fluctuationsmacromolecular substancesProtein aggregationNeutron scatteringFibrilAmyloid fibrilatomic fluctuationprotein aggregationCrystallographyConcanavalin ABiophysicsbiology.proteinGeneral Materials SciencePhysical and Theoretical Chemistry
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