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Article Dans Une Revue Journal of Physical Chemistry C Année : 2016

Multiple Glass Transitions of Microphase Separed Binary Liquids Confined in MCM-41

Résumé

The confinement of fluids in channels of nanometer size presents unprecedented opportunities to reveal emergent physicochemical properties that have no equivalent in the corresponding bulk system. We present an experimental study of fully miscible binary low-molecular weight liquids confined in nanopores. Under these conditions, the mixtures form a microphase-separated state with two regions of different compositions forming the core and the shell of a concentric tubular nanostructure. We combine neutron diffraction and DSC measurements to assess the thermal behavior of this unusual phase. These results show that crystallization is suppressed, leading to glassy behaviors characterized by anomalies in the density and the heat capacity. We reveal the coexistence of two different glass transitions, providing the direct proof for two different enthalpic relaxation times. It leads to the conclusion that the subcomponents of the microphase-separated mixture each obey distinct dynamical behaviors. This phenomenon is all the more unusual considering that the thicknesses of the core and the shell are only one to three molecular sizes. These results have important implications for processes involving interfacial multicomponents fluids, including heterogeneous catalysis, microfluidic devices, nanofiltration or oil industry.
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Dates et versions

hal-01314886 , version 1 (12-05-2016)

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Abdel Razzak Abdel Hamid, Ramona Mhanna, Pierre Catrou, Yann Bulteau, Ronan Lefort, et al.. Multiple Glass Transitions of Microphase Separed Binary Liquids Confined in MCM-41. Journal of Physical Chemistry C, 2016, 120 (20), pp.11049-11053. ⟨10.1021/acs.jpcc.6b04596⟩. ⟨hal-01314886⟩
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