Preparation And Self-assembled Property Of Monodisperse Anatase TiO₂ Nanorods

This thesis carried out the synthesis of anatase TiO₂ nanorods,the study of their self-assembled properties,and a preliminary exploration of TiO₂ nanorods in the application of inorganic liquid crystal materials.We have adopted a unique high-temperature "aminolysis" route to synthesize TiO₂ nanorods(diameter about 1.5 nm,length of 26 - 34 nm) in the TNBT/OLAC/OLAM formula for 1:15:6 mmol,all of which have the same diameter and the self-assembled properties.Moreover,we put forward a distinctive interpretion of aminolysis mechanism in terms of relative reactivity of carbonyl carbons under attack by oleylamine,and then make the specific interpretation on this aminolysis mechanism for our experiments.This study shows by transmission electron microscopy that anatase TiO₂ nanorods of a dipolar character self-assemble into 1D(ribbon),2D(smectic,columnar, domino,honeycomb) and 3D(lamellar) liquid-crystalline ordered superlattices,which may play an important role in exploring new materials and devices in the future.We may narrow down the investigative parameters affecting the assembly behavior roughly to two aspects:evaporation dynamics(i.e.,local concentration,evaporation rate) and directional interactions(i.e.,entropic force,energetic force),shedding light on a careful control of the subtle balance between them in self-assembly.Furthermore, the roles of entropic depletion attractions and energetic dipole-dipole couplings between TiO₂ nanorods in self-assembly process are particularly emphasized.Here we apply the Accelrys Materials Studio software as a new strategy combined with Tasker's classification to theoretically validate the existence of electric dipole moment along the longitudinal axis of TiO₂ nanorods.Finally,this paper successfully used TiO₂ nanorods as inorganic liquid crystal's ingredients,and got the preliminary characterizations under a polarizing optical microscope.We believe that TiO₂ nanorods with self-assembled properties may have great importance for exploring new inorganic liquid crystal materials.