Detection of two glass transitions on triton X-100 under confinement - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Journal of Physical Chemistry C Année : 2013

Detection of two glass transitions on triton X-100 under confinement

Résumé

Because of the strong tendency of Triton X-100 to crystallize, inclusion in a SBA-15 matrix of 5.7 nm in pore diameter was used as a means to suppress crystallization. Clear evidence that Triton X-100 exists under confinement in the amorphous and supercooled state is given by X-ray diffraction supported by differential scanning calorimetry and dielectric relaxation spectroscopy. From the thermogravimetric analysis, a loading degree of 50% (wt) was estimated; the decomposition of confined Triton X-100 follows a two-step profile, indicating that molecules are partitioned between bulklike and adsorbed, the latter fraction being in a higher proportion. This allowed the unequivocal detection by DSC of two well-resolved glass transitions (∼ 20 K apart), which is a remarkable result obtained by conventional calorimetric analysis in confined systems. The two molecular populations have different mobilities giving rise to two different dielectric relaxation processes: an αTr/SBA bulklike process associated with molecules located more in the center of the pores, slightly slowed down relative to bulk α-relaxation, and an S-process due to molecules absorbed at the walls with significantly hindered mobility. Moreover, an MWS process is detected due to interfacial polarization that builds up between the adsorbed Triton X-100 molecules and SBA pore walls whose temperature dependence seems to be correlated with the one of the S-process. The inclusion in SBA-15 revealed to be a good strategy to simultaneously avoid crystallization and achieve a long-term stabilization of the disordered form.
Fichier non déposé

Dates et versions

hal-00910265 , version 1 (27-11-2013)

Identifiants

Citer

E.G. Merino, P.D. Neves, I.M. Fonseca, F. Danéde, A. Idrissi, et al.. Detection of two glass transitions on triton X-100 under confinement. Journal of Physical Chemistry C, 2013, 117, pp.21516-21528. ⟨10.1021/jp404306a⟩. ⟨hal-00910265⟩
59 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More