The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform
Pascal Hebraud - One of the best experts on this subject based on the ideXlab platform.
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Viscoelastic Properties of Poly(vinyl alcohol) Hydrogels Having Permanent and Transient Cross-Links Studied by Microrheology, Classical Rheometry, and Dynamic Light Scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q(0) dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we found Maxwell type viscoelasticity characterized by a crossover frequency (maximum of G '') and G' similar to omega(2) and G '' similar to omega(1) in the lower frequency range. The chemical gels displayed an elastic plateau with low G '' at low frequency. For the dual cross-link gel a maximum of G '' was observed, and its characteristic time agrees with that of the Intermediate Mode measured by DLS. We show that this relaxation Mode corresponds to the associative Rouse Mode characterized by G' = G '' similar to omega(0.5), depending on the dissociation rate of the reversible transient cross links We propose a stress relaxation mechanism of the PVA chains in the presence of elastically inactive but associative transient cross links which induces incomplete stress relaxation.
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viscoelastic properties of poly vinyl alcohol hydrogels having permanent and transient cross links studied by microrheology classical rheometry and dynamic light scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing-wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q0 dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we fo...
Tetsuharu Narita - One of the best experts on this subject based on the ideXlab platform.
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Physical gelation of supramolecular hydrogels cross-linked by metal-ligand interactions: Dynamic light scattering and microrheological studies
Polymer, 2017Co-Authors: Hiroto Ozaki, Tsutomu Indei, Tsuyoshi Koga, Tetsuharu NaritaAbstract:Abstract Microrheology based on diffusing-wave spectroscopy, dynamic light scattering (DLS), and macrorheology were performed on solutions of polyacrylamide-derivative associating polymer containing imidazole groups. By adding Ni ion, the physical gel is formed by metal-ligand bond. The physical gel point, where the percolation of a transient network is supposed to occur, was microrheologically determined. In the DLS measurement showing ergodicity at all the conditions studied, we observed three Modes in the autocorrelation functions: fast, Intermediate, and slow Modes. The fast Mode is the collective diffusion (gel Mode), while the slow Mode is attributed to the diffusion of clusters. For the Intermediate Mode, with increase in Ni ion concentration, the transition from diffusive Mode to relaxation Mode was observed near the microrheologically determined physical gel point. In postgel regime, Intermediate Mode can be attributed to the macroscopic relaxation since the activation energies are comparable with the relaxation energy estimated by macrorheology.
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Viscoelastic Properties of Poly(vinyl alcohol) Hydrogels Having Permanent and Transient Cross-Links Studied by Microrheology, Classical Rheometry, and Dynamic Light Scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q(0) dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we found Maxwell type viscoelasticity characterized by a crossover frequency (maximum of G '') and G' similar to omega(2) and G '' similar to omega(1) in the lower frequency range. The chemical gels displayed an elastic plateau with low G '' at low frequency. For the dual cross-link gel a maximum of G '' was observed, and its characteristic time agrees with that of the Intermediate Mode measured by DLS. We show that this relaxation Mode corresponds to the associative Rouse Mode characterized by G' = G '' similar to omega(0.5), depending on the dissociation rate of the reversible transient cross links We propose a stress relaxation mechanism of the PVA chains in the presence of elastically inactive but associative transient cross links which induces incomplete stress relaxation.
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viscoelastic properties of poly vinyl alcohol hydrogels having permanent and transient cross links studied by microrheology classical rheometry and dynamic light scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing-wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q0 dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we fo...
Martinus J. Buekers - One of the best experts on this subject based on the ideXlab platform.
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the integration of temporally shifted visual feedback in a synchronization task the role of perceptual stability in a visuo proprioceptive conflict situation
Human Movement Science, 2010Co-Authors: Tanja Ceux, Gilles Montagne, Martinus J. BuekersAbstract:The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization Modes (in-phase, anti-phase, and Intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization Mode in contrast to the less stable anti-phase and Intermediate Mode. Our findings suggest that the complexity of the synchronization Mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task.
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The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation
Human Movement Science, 2010Co-Authors: Tanja Ceux, Gilles Montagne, Martinus J. BuekersAbstract:The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, seventeen participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75% and 100% of the target cycle duration) in three synchronization Modes (in-phase, anti-phase and Intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization Mode in contrast to the less stable anti-phase and Intermediate Mode. Our findings suggest that the complexity of the synchronization Mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task.
Tanja Ceux - One of the best experts on this subject based on the ideXlab platform.
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the integration of temporally shifted visual feedback in a synchronization task the role of perceptual stability in a visuo proprioceptive conflict situation
Human Movement Science, 2010Co-Authors: Tanja Ceux, Gilles Montagne, Martinus J. BuekersAbstract:The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, 17 participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75%, and 100% of the target cycle duration) in three synchronization Modes (in-phase, anti-phase, and Intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization Mode in contrast to the less stable anti-phase and Intermediate Mode. Our findings suggest that the complexity of the synchronization Mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task.
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The integration of temporally shifted visual feedback in a synchronization task: The role of perceptual stability in a visuo-proprioceptive conflict situation
Human Movement Science, 2010Co-Authors: Tanja Ceux, Gilles Montagne, Martinus J. BuekersAbstract:The present study examined whether the beneficial role of coherently grouped visual motion structures for performing complex (interlimb) coordination patterns can be generalized to synchronization behavior in a visuo-proprioceptive conflict situation. To achieve this goal, seventeen participants had to synchronize a self-moved circle, representing the arm movement, with a visual target signal corresponding to five temporally shifted visual feedback conditions (0%, 25%, 50%, 75% and 100% of the target cycle duration) in three synchronization Modes (in-phase, anti-phase and Intermediate). The results showed that the perception of a newly generated perceptual Gestalt between the visual feedback of the arm and the target signal facilitated the synchronization performance in the preferred in-phase synchronization Mode in contrast to the less stable anti-phase and Intermediate Mode. Our findings suggest that the complexity of the synchronization Mode defines to what extent the visual and/or proprioceptive information source affects the synchronization performance in the present unimanual synchronization task.
Guylaine Ducouret - One of the best experts on this subject based on the ideXlab platform.
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Viscoelastic Properties of Poly(vinyl alcohol) Hydrogels Having Permanent and Transient Cross-Links Studied by Microrheology, Classical Rheometry, and Dynamic Light Scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q(0) dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we found Maxwell type viscoelasticity characterized by a crossover frequency (maximum of G '') and G' similar to omega(2) and G '' similar to omega(1) in the lower frequency range. The chemical gels displayed an elastic plateau with low G '' at low frequency. For the dual cross-link gel a maximum of G '' was observed, and its characteristic time agrees with that of the Intermediate Mode measured by DLS. We show that this relaxation Mode corresponds to the associative Rouse Mode characterized by G' = G '' similar to omega(0.5), depending on the dissociation rate of the reversible transient cross links We propose a stress relaxation mechanism of the PVA chains in the presence of elastically inactive but associative transient cross links which induces incomplete stress relaxation.
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viscoelastic properties of poly vinyl alcohol hydrogels having permanent and transient cross links studied by microrheology classical rheometry and dynamic light scattering
Macromolecules, 2013Co-Authors: Tetsuharu Narita, Koichi Mayumi, Guylaine Ducouret, Pascal HebraudAbstract:Dynamics of poly(vinyl alcohol) (PVA) hydrogels having chemical and physical transient cross-links simultaneously (dual cross-link PVA gels) were studied by microrheology based on diffusing-wave spectroscopy (DWS), classical rheology and single dynamic light scattering (DLS), and compared with those of corresponding chemical and physical PVA gels. Three different relaxation Modes (fast, Intermediate and slow Modes) are observed for physical gels, while one Mode (fast Mode) is found for chemical gels, and two (fast and Intermediate) for dual cross-link gels. The three Modes are attributed respectively to Brownian diffusion of PVA polymer or collective diffusion of the network or gel Mode (fast Mode), macroscopic stress relaxation (Intermediate Mode whose characteristic time shows q0 dependence) and Brownian diffusion of aggregates (slow Mode). Microrheological measurements are in good agreement with macrorheological showing segmental Rouse Mode dynamics in the high frequency range. For physical gels, we fo...