Topographical Study of Low Temperature Plasma Treated Flax Fibers

A comprehensive study of morphological and topographical changes in low tempera ture plasma treated flax fibers is reported. Time-series images of fiber surface appearance are examined by environmental scanning electron microscopy (ESEM). As the exposure time increases, the depth of the micropores etched by the plasma increases with increasing pore width. The surface fibrils remain on the surface at up to 40 minutes of oxygen plasma or 60 minutes of argon plasma exposure. The dominant fabric weight loss of linen during plasma treatment is mainly attributed to fiber surface etching. Fiber contraction is also observed during plasma treatment. The ESEM micrographs show a good correlation with the SEM micrographs. The depth of the etched pits induced by the argon and oxygen plasma is measured by atomic force microscopy (AFM). On the relatively smooth surface of an untreated flax fiber, the argon plasma creates pits of mainly submicrometer size (both depth and diameter), while the oxygen plasma creates pits of a few micrometers. Image processing techniques provide a quantitative description of the surface topography of plasma treated flax fibers, and the FFT power spectra describe periodic surface features. Changes in the surface roughness of the plasma etched flax fibers are quantified by RMS values.