Electrochemical anodic oxidation of UHMCFs was carried out in acustom-built laboratory set-up which consisted of a surface treatmentbath, a washing bath and a drying oven. The length of the surfacetreatment bath was 1.5 m and an aqueous 5.0 wt% NH4HCO3 solutionwas chosen as the electrolyte. The electric current densities were 0(untreated), 1.0 A/m2, 2.0 A/m2 and 3.0 A/m2, respectively. UHMCFswere thoroughly washed with deionized water in the washing bath afterthe electrochemical anodic oxidation and then dried in an oven at110 °C