Oligomeric Cellulose Co-Crystallization with DMSO

Oligomeric cellulose with a median degree of polymerization of 7 (DP7) is produced by hydrolysis of cellulose in phosphoric acid. DP7 molecular weight distribution was characterized by NMR, MALDI-TOF, and GPC. DP7 is soluble in hot DMSO and crystallizes in the form of spherulites upon cooling. The spherulite morphologies and crystallization kinetics was characterized by polarized optical microscopy. The structure of the crystal has been studied by synchrotron radiation XRD, TEM and MD simulation. The oligomeric cellulose and DMSO co-crystallize. After removing excessive solvent, the crystal is metastable in dry air but transforms into the cellulose II crystal structure when exposed to humidity.