engleski

Interface Phenomena of Textiles

According to definition interface phenomena happens in liquid (bath) and solid (textile) surface contact what is the case in all wet textile processes. Such phenomena, as wetting and wicking, adsorption and particle aggregation, depend on a large extend on the kind and magnitude of the solid surface free energy and surface electrokinetic properties, like zeta potential and specific amount of surface charge. Water and other liquids absorbency mainly depends on wetting and wicking phenomena. Wetting of the textile is the displacement of vapor (textile-air interface) with liquid (textile-liquid) interface. On the other hand wicking is the spontaneous flow of a liquid in a porous substrate, driven by capillary forces and takes places only in the wetted fabrics. For the process to be spontaneous free energy has to be gained and the work of penetration has to be positive. This paper is attempt to clarify these complex phenomena describing in details the measuring method of relevant components for calculation the surface free energy and work of liquid spreading for different pretreated textile fabrics. Method applied is based on Washburn equation for the horizontal capillary and modified by Chibowski. Textiles electrokinetic charge depend on the amount of accessible groups (hydroxyl, carboxyl, sulphate, amino groups and other groups) and the portion of amorphous regions where the adsorption processes take place. In general, specific adsorption of ions or dissociation of the surface groups in aqueous solution results with their surface charge. Fiber surface charge depends upon their molecular and supramolecular structure, swelling capacity as well as upon ionogenity, structure and concentration of adsorbate. These phenomena are crucial for textile dyeing and finishing processes as well as for textile care. They characterize the material electrical charge. Changing the number of functional fiber surface groups, e.g. by blocking in dyeing and finishing processes, and their dissociation affect the distribution of surface charge, as well as the thickness and distribution of the electric double layer which results in different fabric interface phenomena. Paper will describe in details elekrokinetic phenomena, the measuring procedure using the streaming current method developed for textiles.

textile; surface free enery; electrokinetic potential; surface charge

nije evidentirano