3. Results and discussion
3.1. AFM investigation of cellulose nanofibers
Typical tapping mode AFM images of nanofibers obtained after
acid hydrolysis and deposited on a glass substrate are shown in
Fig. 1a–d. AFM height and amplitude images showed bundles of
cellulose nanofibers with ribbon like shape structure. From these
pictures, it is obvious that a considerable reduction in fiber size has
been accomplished by the acid treatment considering an average
size of 20 m for the raw MCC cellulose. The diameter of individual
fibers ranges from 11 to 44 nm with an average of 20
±
6 nm. In
order to have a representative value, this diameter was calculated
on 70 fibers measurements with NanoScope software. To ensure
the repeatability and the accuracy of the AFM scanning, different
zones of the same sample were analyzed and the presented images
are representative of the totality of the sample.