Study On The Dispersion Of Single-walled Carbon Nanotubes By Alkylated Derivatives Of Amino Acids

With the development of nanotechnology,single-walled carbon nanotubes have been widely applied in many fields,which require SWNTs of various qualities.For example,photovoltaic devices and electrochromic devices need single-walled carbon nanotubes of a single(metallic or semiconducting)conductivity,and scanning probe,field emission,drug carrier and other applications require individual single-walled carbon nanotubes.The biocompatibility of single-walled carbon nanotubes,particularly,is the precondition and basis for their application in medical diagnosis and treatment.Thus,research on the dispersion of single-walled carbon nanotubes by biomolecules is of great scientific and practical significance.In this paper,single-walled carbon nanotubes were prepared by dc arc discharge meyhod,and most amorphous carbon and metal catalysts were removed by heat treatment in air and acidification with hydrochloric acid.Ten N-dodecyl derivatived amino acid sodium salts were synthesized by Schotten-Baumann reaction and alkali treatment,and then applied to research on the dispersibility of preliminarily purified single-walled carbon nanotubes.The experimental results show that N-dodecyl leucinate nd N-dodecyl sarcosinate have very good dispersing ability to the single-walled carbon nanotubes prepared by arc discharge method.It is found that the mixed solution of N-dodecyl leucinate and N-dodecyl sarcosinate had a stronger individual dispersing ability for the arc-discharged single-walled carbon nanotubes,reflecting the interaction between these two amino acid derivtives.Though Raman spectra and UV-VIS-NIR absorption spectra,the chiral indices(m,n)of n-dodecyl leucinate and N-dodecyl sarcosinate individually dispersed single-walled carbon nanotubes were assigned.The Raman and FTIR spectra evidenced the electric charge transfer from N-dodecyl leucinate(or N-dodecyl sarcosinate)to single-walled CNTS,which is thought to be the key factor for the good dispersibility of the two amino acid derivatives to single-walled carbon nanotubes.It is expected that the N-dodecyl leucinate or N-dodecyl sarcosinate individually dispersed single-dispersed carbon nanotubes would be applicable in medical diagnosis and treatment.