Surface modification of Multi-walled carbon Nanotubes.pdf

1、The first reported observation of carbon nanotubes was by Iijima in 1991 for multi-wallcarbon nanotubes (MWCNT). It took however, less than two years before single wall carbonnanotubes were discovered experimentally by I

2、ijima at the NEC Research Laboratory inJapan and by Bethune at the IBM Almaden Laboratory in California These experimentaldiscoveries and the theoretical work which predicted many remarkablc properties for carbonnanotube

3、s, launched this field and propelled it forward. The field has been advancing at abreath taking pace ever since with many unexpected discoveries.Caron Nanotubes (CNT)have attracted tremendous attention and numorous poten

4、tial applications have been proposed.CNTs are among the stiffest and strongest materials known, and have remarkable electronicproperties and many other unique characteristics. For these reasons, they have attracted lotso

5、f academic and industrial interest, with thousands of papers on nanotubes being publishedevery year.
　　 In the first part of this thesis, Surface modification of Carbon nanotubes by a reactivebiopolymer- polydopamine

6、 (pdop) was conducted by dispersing CNTs into a solution ofdopamine and mildly stirred at room temperature. Modifying the outer of carbon nanotubes(CNTs) is a promising pathway to manipulate them into solutions, hybrid a

7、ssemblies andnano-devices. Although, success have been achieved in many areas, many available methodshave limitations for widespread practical use; specific examples include the drastic reactionconditions and breakdowns

8、of CNT sidewalls (oxidative acid treatmcnt), the use of complexinstrumentation and multistep procedures (covalent grafting in organic solvent), thelimitations of coating thickness (deposition of proteins etc.) reactivity

9、 and bioactivity(semiconductors). The surface modification doesn't ruin the nanotube sidewalls, and itsthickness was controlled on nanometer by adjusting the reaction time, temperature and pH.Furthcrmore, the coating was

10、 a vc:rsatilc platform for functional organic ad-layers Theresulted coating is a versatile platfonn for both functional organic ad layax Furthermore, alayer film constmction of silverloaded nanotubes has also achieved. T

11、he dispersed andcovered nanotubes were investigated by scanning-Electron Microscopy (SEM),Transmission Electron Microscopy, Fourier-Transmission Infrared (FT-IR), and X-rayPhotoelectron spectroscopy (XPS) in order to ana

12、lyze the evolution of the dispersion and thesurface modification of MWCNT. Silver nanoparticle modified carbort nanotubes pasteelectrodes for determination of Dopamine has been extensively studied and variousapproaches h

13、ave been employed for the preparation of metal nanoparticlcs. Therefore, muchwork has been caITied out into their formation characterization and employment fordetection of many electro actives species. Therefore, modific

14、ation of Carbon nanotubes byoxidative polymerization of dopamine, including Silver has to be improved.
　　 Secondly, Plasma polymerization is a procedure, in which gaseous monomers,stimulated through plasma, condense

15、on freely selectable substrates as high cross-linkedlayers． As the monomer molecules in plasma for the most part become shattered intoreactive particles, there remain at most only partially preserved chemical structures

16、of theoutput gases in the product, which results in cross-linked and disordered structure. Swcturalpreservation and cross-linking gradients can bc controlled through process parameters suchas pressure, working gas-flow a

17、nd applied electrical output; so that one can also construct socalled gradient layers； with increasing degree of cross-linking over the thickness. In thisthesis, thin polymer films were deposited on CNT surface by plasma

18、 polymerization of GMA(Glycidyl methacrylate) under different glow discharge condition. The FT-IR, X-rayphotoelectron spectroscopy (XPS) and gases carricr plasma(oxygen, (O2); Nitronium (N2)and Argon(Ar)) treatment resul

19、ts; suggested that the epoxide functional group8 0f thedeposited film httd been preserved to various extends depending on the plasma depositionconditions The use of low radio frequency power (～80W) and a relatively low s

20、ystempressure 0.6torr readily resulted in the deposition of thin film having nearly the samecomposition of the epoxide functional groups as that of the GMA homopolymer. The plasmapolymerization of GMA (PP-GMA) thin film

21、deposited on the Ar, O2, N2 pretreated CNTsurface, were retained to a large extend, suggesting the presence of covalent bonding betweenthe PP-GMA layer and the CNT surface. In the present work, GMA is plasma polymerized(

22、PP-GMA) and deposited on the plasma pretreaterd Carbon Nanotubes (CNT) surface withthe preservation of a high percentage of the epoxide groups. The plasma polymerized of GMA also pretreated silicon nanocomposites in orde

23、r to study the surface modification, thechemical change and the effect of the plasma polymer of GMA on the CNT/Silicon. FT-IR,DSC, TGA, SEM and FTIR-ATR were conducted and the structure of the silicon waschemically modif

24、ied by the plasma polymerization of Glycidyl methacrylate. Therefore,Fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR) hasproven to be a useful technique for the analysis of surfactants on

25、 the surface of silicone andppGMA films
　　 Thirdly, Multi-wall carbon nanotubes (MWCNT) reinforced silicone rubber (SiR)nanocomposites were successfully prepared through mechanical mixing method usingdicumyl peroxide

26、 (DCP) as a curing agent. The vulcanization reaction of the elastomer ispromoted by the radical decomposition of DCP to obtain the network structure. Themcchanical propcrties of the nanocomposite:s were evaluated. The th

27、ermal stability of thenanocomposites was systematically studied.Measurcments are used primarily to determinethe amount and rate of change in the weight of a material as a function of temperature, andcharactcrizc material

28、s that exhibit weight loss or gain due to decomposition. The dispersionof CNTs in silicone rubber was characterized by Scanning electron Microscopy (SEM).
　　 Finally, the effect of carbon nanotubes loading on the elc

29、ctrical thermal conductivityand Payne effcct were also investigated Furthermore, From DSC study, it has beendetermined that the degree of crystallinity Xc and the super cooling △T, generallycharacterize the crystallizati

30、on behavior of the nanocomposites.A decrease in Xc and △Tindicate that the crystallization rate of the nanocomposites is increased. Afier pyrolysis,with the increase of CNT content, the decomposition rate or/and the weig