Effect of trace electrolyte on liquid crystal type of cellulose microcrystals

The rodlike microcrystal suspension prepared by sulfuric acid hydrolysis of bacterial cellulose was found to undergo spontaneous nematic phase separation after complete desalination. This phase separation was preceded by a birefringent glassy-like state for about 1 week. Addition of trace electrolyte (< 1 mM NaCl) caused remarkable changes in phase separation behavior; i.e., the separation was complete in 2 days and the anisotropic phase became chiral nematic. This phenomenon can be explained by the change in the effective particle shape, from cylindrical to the twisted rod as a result of screening of surface charge.