Abstract

Leather fatliquored with monoakyl phosphate (MAP) possessed an excellent hydrophobicity. In order to elucidate the mechanism of the hydrophobicity due to MAP fatliquoring the binding behaviour and orientation of the MAP molecule (with different alkyl chain lengths) on the surface of chrome leather were examined by X-ray photoelectron spectroscopy (XPS). Differences in the behaviour of MAP and mono alkyl sulphonate (MAS) were also studied by XPS. The interactions of MAP or MAS with the chrome leather are different. MAP combined with the chrome leather with a co-ordination bond and MAS combined chiefly with an ionic bond. The binding strength of MAP varied with the carbon number. The MAP molecule stayed on the fibre surface and a monolayer of MAP molecules was formed. The alkyl chain with C16 or above showed a high condensation force between the side planes and formed a condensed membrane with high density. It can be considered that the hydrophobicity results from the formation of a monolayer of MAP molecules into a condensed membrane.