Micro/nanofibrillated cellulose (MFC/NFC) The MFC and NFC are materials produced generally by chemical or biochemical pretreatments of the cellulosic fibre pulp (e.g. carboxymethylation, enzyme treatment), followed by disintegration into micro/nanofibrils with the aid of high pressure homogenization. The nanofibrils are typically 5-15 nm in diameter, up to 1 µm long, and the microfibrils are of several micrometres long and 20-60 nm in diameter.17,18 The pretreatments lead also to an increase in the content of carboxylic acid groups on the fibre surface. The MFC/NFC is obtained as a viscous, aqueous gel, consisting of cellulose micro/nanofibril aggregates.