3.3. Dispersion characteristicsThe dispersions of acetylated and non-acetylated CNFs inethanol and acetone are presented in Fig. 2. Fig. 2(b) and (d) showsthat the acetylated nanofibers are stable and well-dispersed in bothethanol and acetone after 14 days, as expected while the phase sep-aration observed in those cases of native (unmodified) ones Fig. 2(a)and (c). The non-acetylated nanofibers are not as stable and showa slow sedimentation in the used solvents. C¸ etin et al. (2009) havereported similar results for acetylated cellulose nanowhiskers. Thestability of the nanofiber dispersions in the solvent is expected todepend on the size, surface characteristics, and concentration ofnanofibers. The high stability of the modified nanofibers might bedue to the replacement of OH groups in cellulose by acetyl groups,which are more hydrophobic, resulting in better dispersion. It isworth mentioning that a concentration lower than 1% might beless unstable because of the lower interaction between the fibers.