Chiefly manufactured using TEMPO-mediated oxidation of wood cellulose followed by mechanical dispersion of the  oxidized fibers, CNF has a higher length/diameter ratio (100-150). Its structure includes both amorphous cellulose and crystalline cellulose I. The 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO) used for the selective oxidation of primary alcohol groups in polysaccharides (aqueous NaOCl as primary oxidant in the presence of a catalytic amount of bromide at pH 9-10)24 partly oxidises the primary alcohol groups of water-insoluble cellulose to carboxylate groups.25