| In recent years,one-dimensional nanomaterials have been developed rapidly due to their special structural properties and become the leader of nanomaterials.Its synthesis methods include solvothermal method,electrochemical synthesis,template method,et al.However,owing to the disorder state after synthesis,one-dimensional nanomaterials cannot play their unique structural advantages in functional devices,so they need to be reordered.Interface engineering refers to the physical and chemical process completed at the multiphase interface by adjusting the surface tension,density and other parameters between solvents.As an assembly method of nanomaterials,it has the advantages of high efficiency,stability and low price.This paper focus on how to use the interface project to achieve the ordered assembly of one-dimensional nanomaterials through the control of the physicochemical properties and interface structure unit,in three-phase of water-oil-air interface and two-phase of water-air interface,to construct macroscopic ordered assembly of one-dimensional nanomaterials,mainly to carry out the following several aspects:(1)Inorganic semiconductor nanobelts films and yarns constructed at water-oil-air interface:high quality molybdenum oxide nanobelts,bismuth sulfide nanoribbon,etc.were synthesized by hydrothermal method and evenly dispersed in deionized water.Through the three-phase interface assembly method,molybdenum oxide nanobelts were assembled into tightly stacked and ordered nanostructures at the dichloromethane-air-water interface,and the oriented inorganic semiconductor thin films and yarns were obtained after treatment.The carrier mobility in the oriented film is 400 and 30cm~2/(V·s)in the axial and vertical directions of the nanobelts,respectively,demonstrating the excellent electrical anisotropy.The assembled molybdenum oxide yarn exhibited a highly ordered internal structure and tensile strength up to 120 MPa,which is superior to many similar natural and man-made fibers/yarns.Yarns can also be used in energy harvesting applications,as molybdenum oxide allows ion insertion and detachment in the electrolyte.(2)Inorganic semiconductor nanobelts yarns constructed at water-oil-air interface:inorganic semiconductor yarns constructed at short range are limited in their application due to their limited length.In this section,ultra-long vanadium oxide nanobelts with an aspect ratio of 10~4～10~5 were synthesized by hydrothermal method.High aspect ratio is used to provide the interaction force between the building blocks,and the ordered treatment was carried out to achieve the uniformity of the microstructure and the high strength of the macroscopic structure.At the chloroform-air-water interface,vanadium oxide nanobelts underwent three processes of alignment,assembly and twisting due to the interface pressure,so as to realize the continuous preparation of ordered and high strength pure inorganic semiconductor yarns.Due to its unique structural characteristics,the semiconductor yarn has the characteristics of low density(0.32±0.05 g/cm~3),high flexibility(bendable)and high strength(tensile strength 443 MPa),and can be used for fibrous heat/light-responsive sensors and electrochromic artificial muscles.Electrochemically driven muscle generates 32.56%tensile stroke and 1.54 J/g work capacity,which color simultaneously varies between yellow and dark green.(3)Two-phase interface method to build macroscopic ordered assembly based on the common brushes:the three-phase interface assembly method subjects to some weaknesses because of the utilization of organic solvents,and the two-phase interface assembly has the advantages of environmental friendliness,high efficiency,etc.In this section,common brushes are used to prepare ordered assemblies of various one-dimensional nanomaterials,including silver nanowires,molybdenum oxide nanowires,bismuth sulfide nanowires,and so on.In order to realize the orderly assembly of one-dimensional nanostructures,this section carries out mechanical analysis and regulation of brush coating behavior.Glycerol was used to improve the viscosity of disperse liquid,thus increasing the transverse shear force of brush coating and realizing the parallel arrangement of nanostructures.According to theoretical and ANSYS simulation calculation,when the volume ratio of glycerol to water is 3:1,the transverse shear force increased by 24 times and 20.3 times,respectively.This method has universality and can be applied to a variety of one-dimensional nanomaterials.However,according to the different physical properties of the materials,the brushing effect was also different.Finally,the application of anisotropic conductor and thermoelectric thin film was realized by combining different nanowires.(4)Two-phase interface method to build macroscopic ordered assembly based on the nanobrushes:The structure characteristics of common brush determined that it could not provide accurate induction force.Nanobrushes are the oriented one-dimensional nanomaterial assemblies prepared in the first three sections,and used to improve the contact area between the brush and coating material and increase the shear force,shear efficiency.According to the different physical properties of the brush,the water-based and oil-based nanobrushes were utilized to brush different materials.Water-based nanobrushes include molybdenum oxide nanobelts film/yarn,vanadium oxide nanobelts film/yarn,electrostatic spinning polymer film/yarn,etc.,which can be used for the brush coating of water dispersion solution of various one-dimensional nanomaterials,including silver nanowires,tungsten oxide nanowires,etc.Oil-based nanobrushes include carbon nanotube film/yarn,etc.,and can be used for brush coating of a variety of conjugate polymers,including Poly(3-hexylthiophene),etc.The ordered assembly prepared by this method can be used for electrochromic artificial muscles and other purposes. |
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