Cation-induced Nanowire Self-Assembly And The Fabrication Of Nanowire Aerogel

With the development of nanoscience and nanotechnology,single and individual nanocrystals may be impractical for meeting the growing demands in practical applications.Self-assembly,as one of the "bottom-up" assembly processes,has been recognized as one of the most powerful technologies for integrating various nanostructures.New properties and functionalities may appear after aligning the disordered nanoscal-building blocks in a well-designed pattern.Therefore,there are significant requirements to develop efficient,fast,and universal assembly methods to fabricate nano materials with complicated structures.Focusing on this point,we aim to develop a general method for preparing nanomaterial aerogels whose interaction is enhanced by nanowire assembly.Briefly,after ion being added in nanowire solution,dispersed nanowires(NWs)rapidly aggregate to form small ordered nanowire building blocks.During this process,the assembly mechanism can be revealed by the DFT analysis and large-scale molecular dynamics theoretical evaluation.At the same time,using the principle of cation-induced nanoscal-assembly process and the surface plasmon resonance effect,nanoparticles are regulated in solution and the visual display devices are constructed.The main results are summarized as follows:1.The mechanism of cation-induced self-assembly of one-dimensional nanowires has been explored.Te nanowires witha diameter of 7 nm and surfactant of PVP were synthesized.Coordination bond is formed between-N,=O and divalent metal cation,which act as driving force of the nanowire assembly.According to the DFT theory,we can calculate the binding energy of different metals with PVP and Pb2+show the highest binding energy leading to a stable nanowire assemblies.2.Based on the principle of ion-induced nanowire assembly,a simple and rapid method for synthesizing nanowire aerogels has been introduced by simple heating and supercritical drying process.The results show that the gel method is fast and simple,and the Te nanowires can maintain a fixed shape and have high mechanical strength.Adding a certain amount of other nanomaterials in the process of gelation enable to prepare composite nanomaterial aerogel,which has broad application potentials.3.Based on the principle of cation-induced self-assembly and the surface plasmon resonance effect of gold nanoparticles,a visual pressure response color-changing device can be constructed.Due to the surface plasmon resonance effect of the gold nanoparticles,changing the spacing between adjacent gold nanoparticles allows to show the color of the gold nanoparticle array macroscopically.Using this principle,the micro-assembly of gold nanoparticles in the solution can be tuned by the addition of cations to regulate the refraction and reflection of visible light,thereby resulting in the change in appearance color.