Dresden 2006 – wissenschaftliches Programm
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DY: Dynamik und Statistische Physik
DY 46: Poster
DY 46.65: Poster
Donnerstag, 30. März 2006, 16:00–18:00, P1
Dynamics of glass-forming liquids in soft confinement — •Maria Mayorova1, Reiner Zorn1, Dieter Richter1, and Bernhard Frick2 — 1IFF, FZJ, Germany — 2ILL, Grenoble, France
Effect of soft confinement (microemulsion) on the dynamics of viscous propylene glycol (PG) near its glass transition temperature is investigated.
To determine the size of PG core and its polydispersity measurements by neutron small-angle scattering were performed. The data were fitted by a model combining a Schultz distribution of spheres with a Percus-Yevick type structure factor. This fit displays an value of averaged PG core radius about 0,86 nm.
Elastic scans being obtained with a backscattering (BS) spectrometer reveal a temperature region of crystallization in case of confined PG (heating branch). An earlier onset of glass transition of confined PG could be detected from comparison of the mean square displacement for bulk and confined PG.
Fast dynamic processes (Boson peak (Bp)) were observed with time-of-flight (TOF) spectrometer. There is a clearly visible Bp in the case of bulk PG. For confined PG it is suppressed. As Bp for PG in hard confinement displays just opposite behavior, this suppression can be interpretated as a result of extremely small size of PG core or soft confinement. The data obtained on TOF and BS spectrometers have been combined by Fourier transform. The comparison of scattering function behavior for bulk and confined PG provides information that in the case of confined PG the α relaxation is more stretched.