Wetting characterization of Typha domingensis plant fibers

This article focuses on the characterization of the wettability and surface chemistry of typha fiber as a function of the mechanical or biological extraction process and their location in the leaf. With diiodomethane (CH2I2), non-retted fiber bundles exhibited an average contact angle of approximately 57°, compared to 85° for bundles extracted by retting, representing an increase of about 33%. This change in the contact angle, which can reach 102°, was accompanied by a significant decrease in the nonpolar surface energy component, which fell on average from 30.5 to 15.4 mN/m, corresponding to a reduction of approximately 50%. Measurements made with ethylene glycol (C2H6O2) revealed an inverse evolution of polarity. The average polar component increased from 14.6 to 24.9 mN/m after retting, corresponding to an increase of 41%, indicating a surface becoming more polar after retting, despite higher contact angles, increasing on average from 22° to 34°, an increase of 35%. XPS analysis revealed a more pronounced hydrophilicity of the inner face of the fiber bundles obtained by direct combing, associated with a higher O/C ratio of 0.42 versus 0.14, although FTIR analyses did not permit to observe a significant difference in chemical composition, in terms of functional groups.