ATOMIC FORCE MICROSCOPY OF CELLULOSE MICROFIBRILS - COMPARISON WITH TRANSMISSION ELECTRON-MICROSCOPY

Atomic force microscopy (AFM) and transmission electron microscopy (TEM) have been used to image well-characterized algal cellulose microfibrils. Cross-sections of the microfibrils observed by TEM are square, whereas the AFM topography of these microfibril surfaces shows a rounded profile due to convolution with the shape of the AFM tip. Height and base width measurements taken from cross-sections of these AFM micrographs also show a marked dependence on the scan rate of the AFM tip. AFM images of the surface of the highly crystalline cellulose microfibrils were obtained at atomic resolution under ambient conditions; the images showed periodicities along the microfibril axis of 1.07 and 0.53 nm that may correspond to the fibre and glucose unit repeat distances, respectively.