Europhys. Lett.
Volume 65, Number 3, February 2004
Page(s) 351 - 357
Section Condensed matter: structure, mechanical and thermal properties
Published online 01 January 2004
Europhys. Lett., 65 (3) , pp. 351-357 (2004)
DOI: 10.1209/epl/i2003-10088-0

Quenching of lamellar ordering in an n-alkane embedded in nanopores

P. Huber, D. Wallacher, J. Albers and K. Knorr

Fakultät für Physik und Elektrotechnik, Universität des Saarlandes D-66041 Saarbrücken, Germany

(Received 12 August 2003; accepted in final form 20 November 2003)

We present an X-ray diffraction study of the normal alkane nonadecane $\chem{C_{19}H_{40}}$ embedded in nanoporous Vycor glass. The confined molecular crystal accomplishes a close-packed structure by alignment of the rod-like molecules parallel to the pore axis while sacrificing one basic ordering principle known from the bulk state, i.e. the lamellar ordering of the molecules. Despite this disorder, the phase transitions observed in the confined solid mimic the phase behavior of the 3D unconfined crystal, though enriched by the appearance of a true rotator phase known only from longer alkane chains.

61.46.+w - Nanoscale materials: clusters, nanoparticles, nanotubes, and nanocrystals.
64.70.Nd - Structural transitions in nanoscale materials.
61.10.Eq - X-ray scattering (including small-angle scattering).

© EDP Sciences 2004