2.5.1. Atomic force microscopy (AFM) analysis of cellulose
nanofibers
The structural properties of both cellulose nanofibers and
PLA/cellulose nanofibers composites were studied using an atomic
force microscope (AFM) from Bruker, Santa Barbara, equipped with
a Nanoscope V controller and a MultiMode head. The aqueous suspensions
of cellulose nanofibers were diluted, and one drop was
dried on a glass substrate plate under vacuum for several hours.
The equipment was operated in tapping mode using etched silicon
tip (nominal radius 8 nm) with a cantilever length of 225 m
and a resonance frequency of about 75 kHz. AFM measurements
were performed at room temperature with a scan rate of 1 Hz and
a scan angle of 0◦. The height and the amplitude of the signal were
recorded simultaneously.