The 78th JSAP Autumn Meeting, 2017

Presentation information

Poster presentation

17 Nanocarbon Technology » 17 Nanocarbon Technology(Poster)

[5p-PA1-1~82] 17 Nanocarbon Technology(Poster)

Tue. Sep 5, 2017 1:30 PM - 3:30 PM PA1 (P)

1:30 PM - 3:30 PM

[5p-PA1-12] Evaluation of dispersion properties in nitrogen-doped carbon nanotube(N-CNT) and fabrication of N-CNT/polymer composite films

Naoto Kozakura1, Ousuke Shigehiro1, Toshiyuki Watanabe1 (1.Grad.Sch.Eng.,Tokyo Univ. Agri. And Tech.)

Keywords:carbon nanotube, Solubility Parameter, Composite material

Carbon nanotubes (CNT) have been attracted much attention in the world, because CNT show excellent conductivity, mechanical strengths. As a method to give CNT a new function, hetero atoms are introduced in the backbone of carbon network. Nitrogen-doped carbon nanotubes (N-CNT) which is incorporated nitrogen in CNT is reported by some researchers. Several groups have reported that N-CNT show more excellent conductivity than CNT and unique properties for supporting materials for anchoring nano particles and oxygen reduction reaction catalysts. In this study, we investigate dispersibility of N-CNT synthesized by thermal chemical vapor deposition(T-CVD) and plasma discharge with carbon electrodes in super critical fluid of nitrogen. In addition, we estimate a solubility parameters of N-CNT.
In T-CVD method, N-CNT was synthesized by using acetonitrile as the feeds and the cobalt supported on silica gel as a catalyst. The synthesis temperature was set at 750℃. The flow rate of mixed gas (N2 96.5vol%, H2 3.5vol%) was 100 ml/min. In plasma discharge in supper critical fluid of nitrogen, N-CNTs was synthesized by using graphite electrode as the feeds and ferrocene was cast on electrode as a catalyst. A plasma discharge was generated by applying radio frequency power 100w to the nitrogen gas at 13.56 MHZ for 60 min.
X-ray Photoelectron Spectroscopy was conducted for these products. The atomic percentage (at.%) of nitrogen of N-CNT synthesized by T-CVD (C-N-CNT) was 4.7at.%. The nitrogen content is roughly match to N-CNT by the previously reported CVD. On the other hand, N-CNT synthesized by plasma discharge with carbon electrodes in super critical fluid of nitrogen (S-N-CNT) was 18at.%. The nitrogen content is the top level among reported date with our best knowledge. Therefore, S-N-CNT contains much nitrogen than C-N-CNT.
N-CNT were dispersed into 12 solutions of different and known solubility parameters by a homogenizer. The concentration of N-CNT in the supernatant of the dispersions was estimated by the Beer-Lambert-Bouguer law based on absorbance at 500 nm. The concentration was plotted versus the solubility parameters(dt). The estimated dt value for C-N-CNTs was 22.6 Mpa1/2 and dt value for S-N-CNTs was 28.8 Mpa1/2. Therefore, the solubility parameters can be tuned with increasing the atomic percentage of nitrogen of N-CNT. S-N-CNT can be dispersed into H2O for relatively high solubility parameters and the atomic percentage of nitrogen of N-CNT.
In this presentation, we will discuss influence of solubility parameter between polymer matrix and C-N-CNT on electrical conductivity.