Preparation And Properties Of Titanium Dioxide Materials Through Self-assembling Method

Self-assembly has been widely studied to prepare inorganic materials with various special structures,which provides a simple and low-cost method for producing ensembles of nanoparticles in a controllable manner.Continuing titanium dioxide research is exploring novel and highly promising applications including chromatographic separation,photo catalytic redox reactions and water splitting,dye-sensitized solar cells,lithium ion batteries,gas sensors and drug delivery vehicles.In this paper,two kinds of titanium dioxide nanomaterials with special structures were prepared by self-assembly method.On the one hand,a titanium dioxide particle with a hemispherical shape is prepared by self-assembly using a surfactant as a soft template.On the other hand,rod-shaped cellulose nanocrystals(Cellulose Nanocrystals,CNC)prepared by acid hydrolysis of cellulose microcrystalline(Microcrystalline Cellulose,MCC)as a hard template,a composite material with chiral nematic structure from self-assembling of CNC was prepared by mixing an organic precursors of titania.The main contents are as follows:1、An organic precursor of titanium dioxide,tetrabutyl titanate(Tetrabutyl titanate,TBT)and a surfactant to control the stucture of the product dissolved in a hydrophobic organic solvent.After stirring,the mixed solution was reacted in an open glass container,and the reaction temperature and the reaction humidity were effectively controlled.As a result,a simple interfacial self-assembly method was used to prepare hydrolysis intermediates with hemispherical structure.Finally,after calcining at 450°C,titanium dioxide nanoparticles with hemispherical structure obtained.2、A rod-shaped CNC is prepared by acid hydrolysis of MCC.Since the sulfonic acid group was helically grafted onto the CNC surface,the CNC can form a liquid crystal state with a chiral nematic structure at a certain concentration.It can be found that CNC was about 200 nm in length and 10 nm in width by TEM observation.FT-IR results showed that the chemical structure of MCC and CNC did not change.XRD analysis showed that compared with MCC,the crystallinity of CNC increased.The pure CNC film was found to have birefringence property by observing in polarizing optical microscopy.3、With CNC as a hard template,a composite film was prepared with mixing TBT and CNC suspension.During the film formation process,CNC self-assembled into chiral nematic structure.And the hydrolysis intermediates of TBT evenly attached around CNC and participate in the self-assembly process.SEM and POM observation confirmed that the hydrolysis intermediates of TBT were well mixed in the chiral nematic structure of CNC.With the increase of the content of CNC,the pitch of the obtained film increased,and an obvious "fingerprint" structure could be found.