XPS and contact angle study of cotton surface oxidation by catalytic bleaching

Surface chemistry and wetting properties of cotton fibres as affected by catalytic bleaching have been investigated. Two types of cotton fabric have been analysed: the regular and a model cotton fabric. In the regular – double scoured cotton fabric, cellulose was contaminated with both non-removable and removable impurities including different pigments. The model cotton fabric, previously freed of most removable impurities, was stained for the purpose of this study with one pigment only, i.e. morin, a component that is typically found in native cotton fibre. Bleaching effectiveness of the catalyst based bleaches has been compared to the non-catalyst based bleaching systems. Surface chemical changes of cotton have been identified by XPS. Contact angle and capillary constant of the cotton fabric have been measured applying the Washburn method. This approach has provided the tool to explore and to quantify the chemical and physical effects on cotton fibre after catalytic bleaching. The interrelationship between an increase in capillary constant and the removal of non-cellulosic impurities, characterised by the C1 component in C 1s XPS spectrum, has been elucidated.