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Introduction to soft matter and neutron scattering
Auteur(s): Oberdisse J.
Chapître d'ouvrage: Jdn 23 - French-Swedish Winterschool On Neutron Scattering: Applications To Soft Matter, vol. 188 p. (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01921252_v1
DOI: 10.1051/epjconf/201818801001
Exporter : BibTex | endNote
Résumé: As an opening lecture to the French-Swedish neutron scattering school held in Uppsala (6th to 9th of December 2016), the basic concepts ofboth soft matter science and neutron scattering are introduced. Typical soft matter systems like self-assembled surfactants in water, microemulsions, (co-)polymers, and colloids are presented. It will be shown that widely different systems have a common underlying physics dominated by the thermal energy, with astonishing consequences on their statistical thermodynamics, and ultimately rheological properties – namely softness. In the second part, the fundamentals of neutron scattering techniques and in particular small-angle neutron scattering as a powerful method to characterize soft matter systems will be outlined.
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Enhancing the Mechanical Properties of Glassy Nanocomposites by Tuning Polymer Molecular Weight
Auteur(s): Genix A.-C., Bocharova Vera, Kisliuk Alexander, Carroll Bobby, Zhao Sheng, Oberdisse J., Sokolov Alexei P.
(Article) Publié:
Acs Appl. Mater. Interfaces, vol. 10 p.33601-33610 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01925066_v1
DOI: 10.1021/acsami.8b13109
WoS: WOS:000446919800073
Exporter : BibTex | endNote
17 Citations
Résumé: The addition of nanoparticles to a polymermatrix is a well-known process to improve the mechanicalproperties of polymers. Many studies of mechanical reinforcementin polymer nanocomposites (PNCs) focus on rubberymatrices; however, much less effort concentrates on thefactors controlling the mechanical performance of thetechnologically important glassy PNCs. This paper presentsa study of the effect of the polymer molecular weight (MW)on the overall mechanical properties of glassy PNCs withattractive interaction by using Brillouin light scattering. Wefound that the mechanical moduli (bulk and shear) have anonmonotonic dependence on MW that cannot be predictedby simple rule of mixtures. The moduli increase with increasing MW up to 100 kg/mol followed by a drop at higher MW. Wedemonstrate that the change in the mechanical properties of PNCs can be associated with the properties of the interfacialpolymer layer. The latter depend on the interfacial chain packing and stretching, as well as polymer bridging,which vary differently with the MW of the polymer. These competing contributions lead to the observed nonmonotonicvariations of the glassy PNC moduli with MW. Our work provides a simple, cost-effective, and efficient way to control themechanical properties of glassy PNCs by tuning the polymer chain length. Our finding can be beneficial for the rational designof PNCs with desired mechanical performance.
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Properties and internal structure of thermoresponsive acrylamide based core-shell microgels
Auteur(s): Cors M., Wrede Oliver, Oberdisse J., Hellweg Thomas
Conference: DPG Fruehjahrstagung Berlin (Smart Hydrogels and Hydrogel Based Devices II) (Berlin, DE, 2018-03-11)
Ref HAL: hal-01922483_v1
Exporter : BibTex | endNote
Résumé: A gel is a dispersed system which consists of at least two different components: a solid or flexible mesh and a fluid (water in the present case). Microgels are gels in the size range of 10 nm to 1 μm and can be used in a wide range of applications like drug delivery and smart surface coatings. If the microgel consists of acrylamides like N-isopropylmethacrylamide (NIPMAM) or N-n-propylacrylamid (NNPAM) as network component, they show a volume phase transition (VPT) at a certain temperature, the volume phase transition temperature (VPTT). An increase in temperature above the VPTT leads to an abrupt decrease in size and a decrease in temperature leads to an abrupt increase in size. The VPTT is specific for each monomer. To use microgels in sensors or for nanoactuators the thermoresponse has to be precise. That is why we investigated microgels with a core-shell architecture containing NIPMAM and NNPAM. These particles show a tunable linear change in size between 22 °C and 43 °C. Furthermore, we deposited these microgels on surfaces and investigated the properties of the coating. The properties of these particles and coatings can be adjusted by selecting specific synthesis conditions. We then did small angle neutron scattering (SANS) to determine the internal structure of the core-shell microgel.
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Structure of single-chain nanoparticles: a new model
Auteur(s): Oberdisse J.
(Séminaires)
Donostia International Physics Center (San Sebastian, ES), 2018-10-17
Résumé: Proposition d'une modélisation numérique
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Structure of single-chain nanoparticles studied by SANS
Auteur(s): Oberdisse J.
(Séminaires)
Donostia International Physics Center (San Sebastian, ES), 2018-04-18
Résumé: Structure par diffusion de neutrons aux petits angles
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