Structure Sorting Of Large-Diameter Singel-Walled Carbon Nanotubes By Gel Chromatography

Single-walled carbon nanotubes(SWCNTs)intrigued many scientists because they have abroad applications in electronic,opto-electronic,bio-medical fields etc.owing to their unique electronic structure,special physical and chemical properties.The properties of SWCNTs depend on its physical structure,and a minute difference in their atomic arrangement may lead to huge difference in the property of SWCNT.At present,most methods of growing SWCNTs are only producing SWCNTs mixtures with various structures.These SWCNTs mixtures are difficultly applied for the fabrication of high-performance electronic devices directly.Therefore,it is particularly critical to have a research on separating the structure of SWCNTs.In recent years,gel chromatography has been shown high resolution in separating chirality structure of semiconductor SWCNTs,which diameter is less than 1.1 nm,but it still faces huge challenges when separating the structure of SWCNTs with the diameter greater than 1.1 nm.This paper use gel chromatography to separate the structures of SWCNTs(diameter >1.2 nm)mixtures produced by arc discharge method.In this work,we separated the different structures of large diameter SWCNTs by controlling the interaction force between SWCNTs and dextran gel with double surfactant system(Sodium dodecyl sulfate and Sodium cholate)and NaOH respectively.The results are listed as follows:1)For double surfactant system,we find that when adding Sodium cholate(SC)to SWCNTs aqueous solution dispersed by 0.5 wt% SDS solutions,different structures of SWCNTs is separated.What’s more,with the SC concentration changing,the separated SWNTs structure is different.Therefore,we design a gradient concentration of SC to adjust the interaction force between dextran gel and different SWCNTs structures,and realized the separation of SWCNTs structure.2)For the system controlling the interaction force between SWCNTs and dextran gel by NaOH,we find that when adding NaOH to SWCNTs aqueous solution dispersed by SDS,the interaction force between SWCNTs and dextran gel is increased with the NaOH concentration raising.Furthermore,we design the method of gradient concentration of NaOH,and succeed to separate the SWCNTs structure.In a word,we use double surfactant system and NaOH to control the interaction force between SWCNTs structures and dextran gel firstly,and succeed to separate the large diameter SWCNTs structure.This study proved the possibility of large diameter SWCNTs structure separated by gel chromatography and develops a new method for separating single chirality structure of large diameter SWCNTs.