Dielectric Study of n -Propanol during Physical Vapor Deposition: No Surface Mobility and No Kinetic Stability.

Dielectric relaxation experiments have been performed on n -propanol (NPOH) films during physical vapor deposition at temperatures above and below its glass transition, T g = 97 K. The results for NPOH are compared with those of analogous experiments on methyl- m -toluate (MMT) and 2-methyltetrahydrofuran (MTHF), with all three deposited at the same reduced temperature, 0.82 T g . While MMT and MTHF display clear signs of a highly mobile surface layer, no such feature is observed for NPOH. The existence of this in situ observed mobile surface layer correlates perfectly with the material's ability to form kinetically stable glasses, as NPOH differs from MMT and MTHF by not displaying kinetic stability.