PREMELTING FEATURES AND ACOUSTIC MODE SOFTENING IN THE ROTATOR PHASESOF LINEAR TELOMERS - C17H36

The polymer induced alignment (PIA) technique is presented as a new te chnique to grow single-crystalline films of linear telomers. Combining the PIA technique with special high-resolution Brillouin techniques, it is possible to determine the coefficients of the elastic stiffness tenser of the crystalline state of linear telomers, especially in thei r rotator phases. As model systems we have chosen the perfluoroalkane C20F42 and the linear n-alkane C17H36. A comparison of elastic data ob tained from classically and PIA grown samples proves their equivalence as well as their complementarity. Precursors of critical melting disc overed in the rotator phase of C17H36 are discussed in terms of the an omalous temperature dependence of certain elastic tenser coefficients and of related n-telomers.