Single crystals of chitosan

Lamellar single crystals of chitosan were prepared at 125°C by adding ammonia to a low DP fraction of chitosan dissolved in water. The crystals gave sharp electron diffraction diagrams which could be indexed in an orthorhombic P212121 unit cell with a a  8.07 Å, b  8.44 Å, c  10.34 Å. The unit cell contained two anti-parallel chitosan chains and no water molecules. It was found that cellulose microfibrils from Valonia ventricosa could act as nuclei for inducing the crystallization of chitosan on cellulose. This produced a shish-kebab morphology.