Among these shreds, the small fragments could disperse and float in water. The CNFs were acquired by separation of these floating materials. TEM images of the CNFs produced by sonication are shown in Figure 2. The CNFs seemed to be almost the same size as the cotton-based cellulose nanofibers reported in other studies, with a length of several micrometers and a width of less than 10 nm.18 However, the boundaries of the CNFs are unclear in the TEM images due to the limited hydrolysis of the cellulose amorphous region compared to an acid treatment.