Synthesis,Assembly And Optical Properties Of Colloidal Nanodiscs

Responsive optical nanomaterials have a unique light function micro-nanostructure,which can change the optical properties and flourish in advanced fields,like military,sensing,display and anti-counterfeiting.Nowadays,researchers have developed a class of responsive optical materials in which multiple magneto-optical effects are regulated by a single stimulus.Nevertheless,the development of responsive optical nanomaterials is still in infancy.Specifically,the building block is only limited to 1D anisotropic nanostructures(such as nanorods and nanoellipsoids),which is mainly caused by limited materials and difficulties in assembling anisotropic particles.Thus,it is still greatly a challenging but important to further expand the large family of responsive optical nanomaterials with multiple magneto-optical effects,such as 2D anisotropic nanoparticles colloidal assembly arrays.Herein,our work provides a straightforward and new model for regulation of multiple optical properties.Confronted with the abovementioned scientific problems,our research starts with the preparation of nanodiscs and constructed colloid array.Subsequently,we reveal the mechanism of assembly by SAXS.Finally,we realize the dual magneto-optical regulation of nanodiscs colloid array,the following studies have been conducted in the dissertation:(1)First of all,2D Ni@SiO2 nanodiscs were synthesized by a facile method with uniform morphology,adjustable size and high dispersion.Additionally,these methods can not only improve the charge distribution of the particle surface,but also enable nanodiscs to have a higher degree of freedom in the assembly process.Also,we have successfully solved the scientific problem that building blocks are limited to 1D structure,providing a significant building blocks for smart optical nano materials.Meanwhile,our study provides new insights into a better understanding of the magnetic assembly of 2D colloidal nanostructures.Additionally,it is noticeable that our proposed strategy can be well extended to other kinds of more sophisticated colloidal nanostructures,making it possible in the precise tailoring of anisotropic nanostructures.(2)In chapter 3,our work focuses on controlling the assembly of anisotropic particles,we proposed a strategy focusing on the introduction of a magnetic field to induce their position and orientation.Therefore,we revealed the mechanism of nanodiscs assembly by SAXS and the research conducted suggests that in the absence of a magnetic field,concentrated nanodiscs can self-assemble into a randomly oriented polycrystalline structure driven by the electrostatic repulsive force.While applying a magnetic field,the orientation of the main axis of the nanodiscs aligns along the direction of the field to form a uniformly aligned polycrystalline structure.In addition,it is noteworthy that 2D nanodiscs can be used as potential candidates in magneto-optical nanomaterials,which is of great benefit to enrich the assembly models of anisotropic nanoparticles.(3)Considering the challenge of whether the 2D nanoparticles colloidal array can achieve the regulation of multiple optical properties.In chapter 4,we developed 2D anisotropic Ni@SiO2 nanodiscs colloidal array with multi-magnetic-optical response material,integrated with the properties of the magnetically-response photonic crystal and liquid crystal.Exposed with an external magnetic field,both the photon band gap and birefringence optical properties of 2D anisotropic Ni@SiO2 nanodiscs colloidal array could be effectively regulated.Meanwhile,it is insensitive to changes in magnetic field strength,making it possible to work efficiently under weak magnetic field.Furthermore,we have successfully expanded the choice of targeted materials with multiple magnetooptical effects to more complicated kinds of anisotropic nanostructures.Our work not only developed a new type of smart optical materials,but also provided a new assembly model for condensed matter physics.