AFM observation of the non-solid behaviour of AKD wax

摘要

The lack of understanding of the mechanism of AKD sizing has prompted a number of recent fundamental studies on this topic. These studies have shown that during sizing, AKD does not spread on the surface of a fibre via complete wetting (i.e. macroscopic contact angle = 0°). Several processes, i.e., capillary wicking, evaporation - redeposition and surface diffusion of an autophobic precursor have been identified as contributing to the migration of AKD on a cellulose fibre surface. It has been previously suggested that the migration of the autophobic precursor on a hydrophilic substrate may be due to the freezing point of AKD in a two dimensional mono-molecular layer being lower than that of bulk AKD wax. In this work, we present direct experimental evidence which supports this view. The non-solid behaviour of solid AKD is investigated using optical microscopy, atomic force microscopy and differential scanning calorimetry.