MICRODYNAMICS AND PHASE-EQUILIBRIA IN ORGANIC NANOCRYSTALS

The effects of confinement on various organic molecules have been stud ied by nuclear magnetic resonance (NMR) relaxation techniques (T-2 and T-1 rho) between room temperature and 77 K. Cyclohexane, pentadecane, squalane, and squalene have been constrained within 60 Angstrom porou s silica, and the behaviour of the resulting nanocrystals has been com pared to that of the bulk material. In all cases the molecular dynamic s of the confined material were found to be significantly different fr om the bulk, and there is evidence to suggest that the behaviour is la rgely dependent on the size and shape of the molecules and the resulta nt structural disorder present when constrained within the pores. (C) 1998 Elsevier Science Inc.