The Microscopic Basis of the Glass Transition in Polymers from Neutron Scattering Studies

Frick, B.; Richter, D.

doi:10.1126/science.267.5206.1939

Cited by 329 publications

(213 citation statements)

References 28 publications

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“…First, similar timescale dependences of the dynamics of large molecules have also been made in neutron scattering measurements of chain polymers. 30,31 They have also been seen in computer simulations of silica glasses. 32 Thus, the behaviour discussed here may well be much more general than just its presence in enzymes in solution.…”

Section: Discussionmentioning

confidence: 72%

The dynamic transition in proteins may have a simple explanation

2002

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The transition that has been observed in the dynamics of hydrated proteins at low temperatures (180-230 K) is normally interpreted as a change from vibrational, harmonic motion at low temperatures to anharmonic motions as the temperature is raised. It is taken to be an intrinsic property of proteins and has been associated with the onset of protein functions. Examination of the dynamic behaviour of proteins in solution within a defined timescale window suggests that certain observations can be explained without the need to invoke a discontinuity in the dynamics of proteins with temperature, i.e. the existence of a dynamical transition is not required. This is discussed in the context of recent evidence that enzyme activity is independent of the activation of anharmonic picosecond dynamics and declines steadily with temperature through the apparent dynamic transition, in accordance with the Arrhenius relationship. That similar timescale dependent dynamical behaviour has been observed experimentally in chain polymers, and seen also in computer simulations of silica glasses, suggests that the phenomenon may be of wide general relevance in both simple glassy and more complex polymeric systems.

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Section: Discussionmentioning

confidence: 72%

The dynamic transition in proteins may have a simple explanation

2002

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“…The Boson peak is an excess of modes in the range from 2 meV to 10 meV over the low-energy flat Debye level, following the thermal occupation of a Bose system, i.e., phonons. It can be observed in the reduced VDOS g(E)/E 2 representation, or quite equivalently via the dynamic structure factor, of glasses and amorphous solids 151 . In the case of amorphous water, the measurement of a possible Boson peak is made difficult, mainly because the low-energy range is dominated by the HBB feature.…”

Section: The Boson Peakmentioning

confidence: 99%

X-ray and Neutron Scattering of Water

et al. 2016

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International audienceThis review article focuses on the most recent advances in X-ray and neutron scattering studies of water structure, from ambient temperature to the deeply supercooled and amorphous states, and of water diffusive and collective dynamics, in disparate thermodynamic conditions and environments. In particular, the ability to measure X-ray and neutron diffraction of water with unprecedented high accuracy in an extended range of momentum transfers has allowed the derivation of detailed O–O pair correlation functions. A panorama of the diffusive dynamics of water in a wide range of temperatures (from 400 K down to supercooled water) and pressures (from ambient up to multiple gigapascals) is presented. The recent results obtained by quasi-elastic neutron scattering under high pressure are compared with the existing data from nuclear magnetic resonance, dielectric and infrared measurements, and modeling. A detailed description of the vibrational dynamics of water as measured by inelastic neutron scattering is presented. The dependence of the water vibrational density of states on temperature and pressure, and in the presence of biological molecules, is discussed. Results about the collective dynamics of water and its dispersion curves as measured by coherent inelastic neutron scattering and inelastic X-ray scattering in different thermodynamic conditions are reported

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“…These suggest the existence of an excess vibrational density of states over and above the predictions of the Debye model: at the maximum in C p /T 3 , the vibrational density of states, D(ω), scaled with the DOS of a perfect crystal, goes through a maximum which is called the "Boson peak" [17][18][19][20][21][22]. The relation between the Boson peak and the disorder remains a topic that is hotly debated [12,13]; it seems clear that there is some relation between the two, but a direct link between the Boson peak and structural disorder in glassy systems has been difficult to demonstrate [17][18][19][20][21][22][23][24][25].…”

Section: Copyright C Epla 2014mentioning

confidence: 99%

Disorder and excess modes in hard-sphere colloidal systems

Zargar¹,

Russo²,

Schall³

et al. 2014

EPL

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Disorder and excess modes in hard-sphere colloidal systemsZargar, R.; Russo, J.; Schall, P.; Tanaka, H.; Bonn, D. Published in: Europhysics Letters DOI:10.1209/0295-5075/108/38002 Link to publication Citation for published version (APA):Zargar, R., Russo, J., Schall, P., Tanaka, H., & Bonn, D. (2014). Disorder and excess modes in hard-sphere colloidal systems. Europhysics Letters, 108(3), [38002]. DOI: 10.1209/0295-5075/108/38002 General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Abstract -The anomalous thermodynamic properties of glasses remain incompletely understood, notably the anomalous peak in the heat capacity at low temperatures; it is believed to be due to an excess of low-frequency vibrational modes and a manifestation of the structural disorder in these systems. We study the thermodynamics and vibrational dynamics of colloidal glasses and (defected) crystals. The experimental determination of the vibrational density of states allows us to directly observe a strong enhancement of low-frequency modes. Using a novel method (Zargar R. et al., Phys. Rev. Lett. 110 (2013) 258301) to determine the free energy, we also determine the entropy and the specific heat experimentally. It follows that the emergence of the excess modes and high values of the specific heat are directly related and are specific to the glass: even for solids containing a very large amount of defects, both the low-frequency density of states and the specific heat are significantly smaller than for the glass.

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The Microscopic Basis of the Glass Transition in Polymers from Neutron Scattering Studies

Cited by 329 publications

References 28 publications

The dynamic transition in proteins may have a simple explanation

The dynamic transition in proteins may have a simple explanation

X-ray and Neutron Scattering of Water

Disorder and excess modes in hard-sphere colloidal systems

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