Preparation And Application Of Cellulose-Derived Functionalized Nanofibers And Their Assemblies

Due to their advantages of environmental friendliness and low cost,cellulose derived materials have attracted extensive attention recently.With the development of nanotechnology,the various established extraction and preparation processes of nanofibrillated cellulose(NFC)have laid a solid foundation for the development of functionalized cellulose derived materials.The source of NFC is the biomass of plants,animals and bacteria widely existing in the nature.Its excellent mechanical properties,biocompatibility and tunable self-assembly determine the nanocellulose itself has important applications in many fields such as catalysis,energy storage and transformation,functional paper,environmental restoration.In addition,the synthesis and preparation of various kinds of nanomaterials and nanocomposites,including polymers,metals,metal oxides,inorganic-organic composites,and carbon nanomaterials,are inseparable from the participation of nanocellulose.Although researchers have made many important advances in the preparation and application of nanocellulose materials,how to use nanocellulose as a one-dimensional(1D)structural unit template,how to achieve functionalized cellulose derived nanomaterials by rational design,simple and efficient methods are still the key scientific issues that need to be solved urgently.Based on the regulation of functional groups on the surface of cellulose nanofibers and template effect,we prepared a variety of functional nanofibers and related aerogels,thin film materials,including carbon nanofibers,metal-organic frameworks(MOFs)nanofibers,amorphous calcium carbonate(ACC)nanofibers.Cellulose derived ultrathin CNFs aerogels have application potential as electrode materials in supercapacitors.The MOF nanofiber materials can be used in sewage treatment and organic reaction catalysis.The main research results can be summarized as follows:1.An efficient and sustainable method for the fabrication of mechanically stable carbon nanofiber(CNFs)aerogels has been developed by engineering the thermal decomposition chemistry of wood cellulose nanofibers(Wood-NFC).Such wood-derived CNFs aerogels possessed an electrically conductive 3D nanofibrous network structure with a large specific surface area and exhibited promising potential as binder-free electrode materials for supercapacitor.The catalytically thermal conversion of inexpensive and earth-abundant precursors into high value-added carbon materials described in the present work shed new light on the future development of renewable materials by green chemistry.2.A facile template method has been developed for the synthesis of different one-dimensional(1D)MOF nanofiber materials and 1D MOF nanofibers are processed in solution phase to form homogenous macroscopic membrane or thin film materials.The MOF thin films can be prepared on various substrates and free-standing MOF membranes can be prepared with good flexibility.The characterization of the membranes showed that the MOF nanofibers are highly crystalline and remain porous,which is conducive to applications like rapid removal of organic micropollutants and heterogeneous catalysts in reactions.Moreover,the continuous flow synthesis can guarantee the large-scale of MOF nanofibers production.This general strategy in solution processing and synthesis,accompanied by the new morphology of 1D MOFs with high flexibility and processibility,would herald an era in promoting the industrial application of MOFs.3.Based on the cellulose-derived MOF nanofiber membrane,we proposed a secondary growth method using MOF nanofibers as seed crystals on the membrane surface to synthesize continuous and defect-free crystalline MOF thin film materials.The application of this crystalline MOF thin film material in the field of gas separation was investigated.4.Taking cellulose nanofiber as a one-dimensional template,we used the traditional gas-phase diffusion method to synthesize one-dimensional amorphous calcium carbonate(ACC)nanofiber materials.In order to realize the rapid synthesis of amorphous calcium carbonate nanofibers,we proposed a new polyol solvent method to fabricate ACC nanofiber materials with uniform diameters and cross-linked networks at room temperature,which provides new ideas and reference for the synthesis of amorphous calcium carbonate nanomaterials.At the same time,the successful synthesis of ACC nanofibers provides a basis for the assembly of relevant macroscopic film or block materials.