Tunable wicking behavior via titanium oxide embedded in polyacrylonitrile nanofiber strings of yarn

The effect(s) of TiO 2 nanoparticles on the vertical wicking behavior observed in electrospun polyacrylonitrile (PAN) nanofiber strings of yarn was investigated in this study. The capillary flow was measured in composite nanofiber strings of yarn by means of the image analysis of the rise of colored liquid soaked up in the strings of yarn; the height of liquid rise was determined as a function of time. The kinetics of capillary rise follows the Lucas–Washburn’s equation. The results obtained from the experimental design showed that the rate coefficient of the capillary rise was influenced by TiO 2 nanoparticles more than the twist level in nanofiber strings of yarn. For various hot-stretching ratios, the rate of capillary rise decreased with increasing the number of TiO 2 nanoparticles and the level of yarn twist. This decreasing trend was more pronounced at higher levels of yarn twist. To find how capillary behavior changed with the release of nanoparticles, the wicking mechanisms were measured at different concentrations of TiO 2 nanoparticles in capillary liquid. When TiO 2 nanoparticles were used in capillary liquid, they immediately filled the spaces between nanofibers in yarn and the liquid could not rise any more. The present study indicated that the wicking behavior of composite nanofiber strings of yarn was tunable provided that appropriate constructive factors, that is to say, the number of TiO 2 nanoparticles and the level of nanofiber yarn twist, were chosen.