Fundamental Studies on Functionalization of Cellulosics by Control of Their Molecular Assemblies

This research project concerns the fundamental studies on the formation of organized molecular assemblies by cellulose derivatives，especially on the formation of liquid crystals and Langmuir-Blodgett(LB)films.To this end，we have prepared various types of novel cellulose derivatives by utilizing conventional polymer reactions。The results revealed that(1)cellulose ether derivatives having a flexible substituent of appropriate length can form a cholesteric mesophase and undergo a thermally induced inversion of helicoidal sense at a characteristic temperature，depending on the length of flexible substituent and main chain.(2)The ester derivatives such as cellulose triacylates do not form a cholesteric mesophbut a nntypes of columar ar derivatives such as cellulose triacylates do not form a cholesteric mesophase but a ntypes of columar cellid cellides of cellible substatives having a.(2)The ester derivatives such as cellulose triacylates of temperatureIt was found that completely homogeneous mono-and multi-layer films are formed with esters derived from cellulose，while other derivatives including tri-O-alkyl celluloses cannot form a homogeneous mono-layer.The results were discussed from a viewpoint of novel functionalization of cellulosics.

This research project concerns the fundamental studies on the formation of organized molecular assemblies by cellulose derivatives, especially on the formation of liquid crystals and Langmuir-Blodgett(LB) films. To this end, we have prepared various types of novel cellulose derivatives by utilizing conventional polymer reactions. The results revealed that(1) cellulose ether derivatives having a flexible substituent of appropriate length can form a cholesteric mesophase and undergo a thermally induced inversion of helicoidal sense at a characteristic temperature, depending on the length of flexible substituent and main chain.(2) The ester derivatives such as cellulose triacylates do not form a cholesteric mesophase but a new type of columnar liquid crystal.(3) Cello-oligosaccharides including cellobiose are very interesting mesogens.As to LB films, different types of amphiphilic ester and ether derivatives were prepared from cellulose and cellulose derivatives and the fine structure of mono- and multi-layer films was examined by electron microscopy and fluorescence spectroscopy. It was found that completely homogeneous mono- and multiーlayer films are formed with esters derived from cellulose, while other derivatives including tri-O-alkyl celluloses cannot form a homogeneous monoーlayer.The results were discussed from a viewpoint of novel functionalization of cellulosics.