This title appears in the Scientific Report : 2014 

Thermal properties and vibrational density of states of a nanoconfined discotic liquid crystal
Krause, Christina (Corresponding Author)
Zorn, Reiner / Frick, Bernhard / Schönhals, Andreas
Neutronenstreuung ; ICS-1
Neutronenstreuung ; Neutronenstreuung; JCNS-1
Colloid & polymer science, 292 (2014) 8, S. 1949 - 1960
Berlin Springer 2014
10.1007/s00396-014-3247-3
Journal Article
JCNS
Soft Matter Composites
Please use the identifier: http://dx.doi.org/10.1007/s00396-014-3247-3 in citations.
Neutron scattering is employed to investigate the vibrational density of states (VDOS) of the discotic liquid crystal 2,3,6,7,10,11-hexakis[hexyloxy] triphenylene (HAT6) confined to the pores of alumina oxide membranes with different pore sizes. Additionally, the phase transitions were studied by differential scanning calorimetry. The transitions were observed down to the smallest pore size. The decrease of the transition enthalpies versus inverse pore size for both transitions implies an increase of the amount of disordered amorphous material. By extrapolation of its pore size dependence, a critical pore diameter for structure formation of 17 nm is estimated. Similar to the bulk, excess contributions to the VDOS (Boson peak) are also observed for confined HAT6. The Boson peak gains in intensity and shifts to lower frequencies with decreasing pore diameter. This is discussed in the framework of a softening of HAT6 induced by the confinement due to a less-developed plastic crystalline state inside the pores compared to the bulk.