Surface characterization of polyester fibers

Fibers made from poly(ethylene terephthalate) (PET) are characterized by a hydrophobic surface with low reactivity. Modifications of the PET surface to render a higher degree of hydrophilicity and reactivity are therefore common. The modification often involves a surface layer of only a few nanometers thickness. The relatively low fraction of the modified surface layer and the fact that it is generally an organic modification on a thin curved organic substrate presents difficulties in surface analyses. Surface characterization is, however, of high importance in the evaluation of the degree and durability of a given surface modification. The paper will discuss the possibilities and the limits of using wettability studies according to the Wilhelmy method to evaluate the degree of surface modification and its permanence. Comparison between internal and external reflection Fourier‐transform infrared spectroscopy will be made. The use of electron spectroscopy for chemical analysis, secondary ion mass spectrometry, laser microprobe mass analysis, and microprobe molecular optics laser examiner will be illustrated. Data will be presented from studies of model yarns and films coated with D‐417 dip.