Favorable 3D-network formation of chitin nanofibers dispersed in water prepared using aqueous counter collision

In this study, chitin nanofibers were at first successfully prepared using aqueous counter collision (= ACC) method. Dispersion states of the chitin nanofibers in water were compared with aqueous dispersion of cellulose nanofibers in dynamic viscoelastic properties. Morphology of the chitin nanofibers was observed by transmission electron microscopy and polarizing light microscopy. As a result, the ACC treatment provided aqueous dispersion of chitin nanofibers having width of 10-20 nm, and repetition of the treatment allowed a homogeneous aqueous dispersion of the similar sized nanofibers, instead of further pulverization, from the intermediately treated mixture containing different scaled chitin fibers co-existed. The homogeneous dispersion containing chitin nanofibers exhibited much higher dynamic storage and loss moduli when compared with an aqueous cellulose nanofiber system. The dynamic storage modulus of the chitin dispersion tended to increase with increase in the amount of such homogeneous nanofibers, differing from the case of nano-size effects found in the cellulose system that was oppositely decreased. This indicated that the chitin nanofibers dispersed in water were likely to engage a more favorable network.