The processes of low temperature plasma treatment of polyamide fiber were systemically studied. Ripple-like structures in sub-micron size perpendicular to fiber axis were observed under particular treatment parameters. Suggested explanations were given of the mechanisms that produce the structure after the processes of plasma treatment. The fundamental approach used in modelling was considered the temperature profile of the material during the treatment. The morphological study results showed that the stress-field inside the fiber and the degree of crystallinity are essentially important in contributing to structure formation. (c) 2006 Elsevier B.V. All rights reserved.