Synthesis And Electrochemical Properties Of Nanospheres With Controllable Structural Parameters

The morphology and size of nanomaterials have great influence on the electrochemical performance and the stability of devices.People design and control the morphology of nanomaterials through different methods and ideas to improve the capacity and stability of the material by improving the morphology.In recent years,a lot of research results have been obtained by using surfactants as templates to construct nanostructures in different dimensions,mainly because the active molecules of surfactants can be adsorbed in the nucleation centers of crystals.Therefore,it is considered to be a very suitable structural directing agent,and surfactants are a kind of active molecules which can form thermodynamically stable natural nanoscale aggregates at the solution and interface.It provides a variety of possibilities for the construction of nanoparticles with different structure.Based on this,the effect of changing the length of hydrophilic and hydrophobic chain on the self-assembly behavior of surfactants and the morphology of the as-prepared nanoparticles were studied.The influence of different morphology and structure on the electrochemical properties of the material was also included.Octylphenol polyoxyethylene ether surfactants?OP10,OP20,OP30,OP40?with different ethoxy chain lengths were used as templates.Aniline and pyrrole were used as carbon source to prepare nanoparticles by redox reaction.The effects of hydrophilic chain length and hydrophobic chain length on the morphology of nanospheres were studied.The morphology and pore structure of the material were characterized by dynamic light scattering,scanning electron microscope,transmission electron microscope and nitrogen adsorption and desorption curves.The results show that the hydrophilic chain was long in10EO-30EO.The diameter of carbon nanospheres decreased with the increase of hydrophilic chain length.The particle size of EO-?30?-CNS is minimum 36nm,with high specific surface area of 2300m²g^-1and excellent electrochemical performance of 220F g^-1at 1A g^-1.Fatty alcohol polyoxyethylene ether surfactants with different hydrophobic alkane chain lengths?C8,C10,C13,C16?were used to study the effect of hydrophobic chain length on the particle size of polymer nanospheres,with the increase of hydrophobic chain length?C8-C16?,the particle size of polypyrrole nanospheres decreased and the morphology was uniform,the minimum particle size was 47nm.At the same time,PNS-C16 has the largest specific surface area 57m²g^-1and an obvious mesoporous distribution,which indicates that the change of chain length not only improves the morphology and properties of the material.It also has an obvious effect on the pore structure of the material.Not only the influence of hydrophilic and hydrophobic chain length on the particle size is explored,it can be found that the self-assembled form of surfactant also has a certain effect on the structure of nanoparticles.When surfactants are self-assembled into micelles of several nanometers,the nanocrystalline particles are hollow structure,while when they are assembled into vesicle of hundreds of nanometers,the prepared nanoparticles are solid structures.In summary,adjusting the molecular structure of surfactants can effectively regulate the morphology and structure of the materials,which is more effective than the adjustment of concentration.The regulation of hydrophilic chain and hydrophobic chain and the effect of self-assembled morphology on the structure of nanoparticles are also obtained.This work provides a new strategy for controlling the particle size and morphology of nanoparticles,and provides some guiding ideas for the selection of surfactant templates.