High-resolution solid-state C-13 NMR spectra of long-chained n-alkanes included in the nano-channel of MCM-41 have been observed. Each spectrum has two sets of peaks: one from very flexible molecules and the other from molecules with no significant flexibility. These molecules are characterized by carbon spin lattice relaxation times, T-1, of < 10 s and > 10 s. respectively. This phenomenon is ascribed to phase separation of the alkanes in the nano-channel. i.e., the amorphous and crystalline phases. respectively. The mechanism of this phase separation and the dynamics of these molecules in the nano-channel are discussed. (C) 2004 Elsevier B.V. All rights reserved.