Berwanger, RenéRenéBerwangerHenschel, AnkeAnkeHenschelKnorr, KlausKlausKnorrHuber, PatrickPatrickHuberPelster, RolfRolfPelster2022-06-032022-06-032009-03-31Physical Review B 79 (12): 125442 (2009-05-08)http://hdl.handle.net/11420/12805We present a combined x-ray diffraction and infrared spectroscopy study on the phase behavior and molecular dynamics of n-hexadecanol in its bulk state and confined in an array of aligned nanochannels of 8 nm diameter in mesoporous silicon. Under confinement the transition temperatures between the liquid, the rotator RII and the crystalline C phase are lowered by approximately 20K. While bulk n-hexadecanol exhibits at low temperatures a polycrystalline mixture of orthorhombic beta- and monoclinic gamma-forms, geometrical confinement favors the more simple beta-form: only crystallites are formed, where the chain axis are parallel to the layer normal. However, the gamma-form, in which the chain axis are tilted with respect to the layer normal, is entirely suppressed. The beta-crystallites form bi-layers, that are not randomly orientated in the pores. The molecules are arranged with their long axis perpendicular to the long channel axis. With regard to the molecular dynamics, we were able to show that confinement does not affect the inner-molecular dynamics of the CH_2 scissor vibration and to evaluate the inter-molecular force constants in the C phase.en1550-235X200912American Physical SocietyPhysics - Materials SciencePhysics - Materials SciencePhysics - Soft Condensed MatterPhysikJournal Article10.1103/PhysRevB.79.1254420905.1268v1Journal Article