Inelastic neutron scattering for investigating the dynamics of confined glass-forming liquids

Frick, B.; Alba‐Simionesco, Christiane; Dosseh, Gilberte; Quellec, C. Le; Moreno, Angel J.; Colmenero, Juan; Schönhals, Andreas; Zorn, Reiner; Chrissopoulou, K.; Anastasiadis, Spiros H.; Dalnoki-Veress, Kari

doi:10.1016/j.jnoncrysol.2005.03.061

Cited by 55 publications

(50 citation statements)

References 40 publications

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“…Moreover, the β-relaxation, corresponding to the local motions, is quite similar between the bulk and the confined polymer. 40 In other studies, however, where the polymer-inorganic interactions are more attractive, the α-relaxation observed is much slower than the bulk polymer. 46,57−60 In the present work, the dynamics of three different generations of a hyperbranched polyester polyol, Boltorn, is investigated in the bulk and, for the first time, under severe confinement when the polymers are intercalated between the layers of layered montmorillonite, Na + -MMT.…”

Section: Introductionmentioning

confidence: 94%

Dynamics of Hyperbranched Polymers under Confinement: A Dielectric Relaxation Study

Androulaki

Chrissopoulou

Prevosto

et al. 2015

ACS Appl. Mater. Interfaces

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The effect of severe confinement on the dynamics of three different generations of hyperbranched polyesters of the Boltorn family is investigated by dielectric relaxation spectroscopy (DRS). The polymer chains are intercalated within the galleries of natural montmorillonite (Na+-MMT), thus forming 1 nm polymer films confined between solid walls. The structure of the nanocomposites is studied with X-ray diffraction and the thermal behavior of the polymers in bulk and under confinement is determined by differential scanning calorimetry. The glass transition temperatures of the polymers show a clear dependence on the generation whereas the transition is completely suppressed when all the polymer chains are intercalated. The dynamic investigation of the bulk polymers reveals two sub-Tg processes, with similar behavior for the three polymers with the segmental relaxation observed above the Tg of each polymer. For the nanocomposites, where all the polymer chains are severely confined, the dynamics show significant differences compared to that of the bulk polymers. The sub-Tg processes are similar for the three generations but significantly faster and with weaker temperature dependence than those in the bulk. The segmental process appears at temperatures below the bulk polymer Tg, it exhibits an Arrhenius temperature dependence and shows differences for the three generations. A slow process that appears at higher temperatures is due to interfacial polarization.

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Section: Introductionmentioning

confidence: 94%

Dynamics of Hyperbranched Polymers under Confinement: A Dielectric Relaxation Study

Androulaki

Chrissopoulou

Prevosto

et al. 2015

ACS Appl. Mater. Interfaces

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“…In general, transport properties of solvent molecules or solvated ions are highly influenced by confinement at the nano-scale. Size, shape and connectivity of the confining matrix, together with the nature of the charged interfaces and the interplay among hydrophobic, electrostatic and Van der Waals forces, have been shown to significantly alter the fluid properties compared to those of the bulk [7][8][9][10][11][12] . Most part of these studies has focused on confinement in hard matrices but, more recently, the interest in soft confinement, where boundaries mobility cannot be neglected, has substantially grown 13,14 .…”

Section: Introductionmentioning

confidence: 99%

Water confined in self-assembled ionic surfactant nano-structures

2015

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We present a coarse-grained model for ionic surfactants in explicit aqueous solutions, and study by computer simulation both the impact of water content on the morphology of the system, and the consequent effect of the formed interfaces on the structural features of the adsorbed fluid. On increasing the hydration level at ambient conditions, the model exhibits a series of three distinct phases: lamellar, cylindrical and micellar. We characterize the different structures in terms of diffraction patterns and neutron scattering static structure factors. We demonstrate that the rate of variation of the nano-metric sizes of the self-assembled water domains shows peculiar changes in the different phases. We also analyse in depth the structure of the water/confining matrix interfaces, the implications of their tunable degree of curvature, and the properties of water molecules in the different restricted environments. Finally, we discuss our results compared to experimental data and their impact on a wide range of important scientific and technological domains, where the behavior of water at the interface with soft materials is crucial.

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“…The signature of the glass transition is a molecular relaxation process known as the a-relaxation, characterized by cooperativity of the motions and high dynamical heterogeneity, which leads to a broad distribution of relaxation times [3]. A variety of spectroscopic techniques has been used at that aim, in particular broadband dielectric spectroscopy [2,4,5], neutron inelastic scattering [6] and dynamical mechanical spectroscopy [7]. A fruitful approach to the study of the problem at a microscopic level is offered by Nuclear Magnetic Resonance experiments [8], thanks to its selectivity and versatility.…”

Section: Introductionmentioning

confidence: 99%

Probing with Nuclear Magnetic Resonance echo decay and relaxation: A study on nitrile butadiene rubber

Sturniolo¹,

Pieruccini²,

Corti³

et al. 2013

Solid State Nuclear Magnetic Resonance

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Inelastic neutron scattering for investigating the dynamics of confined glass-forming liquids

Cited by 55 publications

References 40 publications

Dynamics of Hyperbranched Polymers under Confinement: A Dielectric Relaxation Study

Dynamics of Hyperbranched Polymers under Confinement: A Dielectric Relaxation Study

Water confined in self-assembled ionic surfactant nano-structures

Probing with Nuclear Magnetic Resonance echo decay and relaxation: A study on nitrile butadiene rubber

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