8th Liquid Matter Conference September 6-10, 2011 Wien, Austria ...

Thu 811:10-14:00P7.97Glass transitions of confined molecular liquids andnanoparticle-elastomer compositesMarius Reinecker, 1 Johannes Koppensteiner, 1 Armin Fuith, 1 Antoni Sánchez-Ferrer, 1 Raffaele Mezzenga, 2 and Wilfried Schranz 11 Universität Wien, Boltzmanngasse 5, 1090, Wien, Austria2 ETH Zürich, Zürich, SwitzerlandWe use TMA and DMA to study the thermal expansion, as well as temperature and frequencydependence of the dynamic elastic susceptibility of glass-forming liquids in mesoporous confinement[1, 2] and polymer nanocomposites [3]. Although these systems are quite different, theyshare some interesting properties. For an attractive interaction between molecules and pore walls,the dynamics of molecular liquids in pores can be drastically slowed down in the vicinity of thepore walls [4] as compared to the centre of the pores. This dynamical decoupling of moleculescan lead to a second glass transition at T g2 [1] at higher temperature as the main vitrification processwhich occurs at T g1 . After coating the pore surfaces with HMDS as a silylating agent, themolecule-pore surface interaction was drastically reduced, leading to a constant relaxation timeacross the pore cross section and a single glass transition. Similar two-glass transition behaviourwas previously found in polymers filled with silica nanoparticles and random ionomers [5]. Herewe present evidences for two glass transitions from DMA measurements (Fig. 2) in a microphaseseparated polyurea elastomer and two elastomeric samples filled with inorganic nanotubes MoS 2or nanowires Mo 6 S 2 I 8 . Similarities and differences with confined molecular liquids will be discussed.[1] J. Koppensteiner, W. Schranz and M. R. Puica, Phys. Rev. B 78, 054203 (2008).[2] J. Koppensteiner, W. Schranz and M. A. Carpenter, Phys. Rev. 81, 024202 (2010).[3] A. Fuith, M. Reinecker, A. Sánchez-Ferrer, R. Mezzenga, A. Mrzel, M. Knite, I. Aulika,M. Dunce and W. Schranz, Dynamic- and thermo- mechanical analysis of inorganic nanotubes/elastomercomposites, submitted to Sensors & Transducers.[4] P. Scheidler, W. Kob, and K. Binder, Eur. Phys. J. E 12, 5 (2003).[5] G. Tsagoropoulos and A. Eisenberg, Macromolecules 28, 6067 (1995).97