A gas shower system was introduced to improve the growth of single-walled carbon nanotube (SWNT) forests by controlling the gas flow direction. Delivery of gases from the top of the forest enabled direct and precise supply of ethylene and water vapor to the Fe catalysts. As such, this approach solved one of the limiting factors of water-assisted chemical vapor deposition method (CVD), that is, delivery of the very small optimum water level to the catalysts. Consequently, this approach improved SWNT forests growth stability, uniformity, reproducibility, carbon efficiency (32%), and catalyst lifetime. With this improved growth, we could synthesize a 1 cm tall forest with 1 x 1 cm size. Also we employed this approach to grow an A4 size SWNT forest to highlight the scalability of water-assisted CVD.

No abstract

N,N′-Diphenyl-1,4-benzoquinone diimine (PBI), which is the minimum redox-active unit of polyaniline, was reduced to N,N′-diphenyl-1,4-phenylenediamine (PDA) derivatives through Michael-type additions of some nucleophiles. The addition of thiophenol to PBI proceeded very rapidly. The polyaddition of PBI-endcapped monomers (P-2PBI, B-2PBI, and TB-2PBI) with thiobisbenzenethiol (TB) produced the novel thermostable oligo(thio-1,4-phenylene)s (OTP) having PDA units as a redox-active site (OTP-P-PDA, OTP-B-PDA, and OTP-PDA). This polymerization proceeded at room temperature without catalysts. OTP-P-PDA, one of the oligomers obtained, was found to have a moderate molecular weight (Mw 8400) and to possess good thermostability (Td10% 400 °C). The polymerization based on Michael-type additions was also confirmed by NMR measurements. The oligomers obtained behaved as good electro-responsive materials. The redox process was determined by the slope of the Nernst plot that involved two electrons and two protons per PDA unit.

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[figure: see text] A novel poly(thiophenylene) having N,N-diphenyl-1,4-phenylenediamine (PDA) as a redox unit was synthesized through a Michael-type addition. This polymerization proceeded at room temperature without catalysts. The polymer obtained acted as a good electroresponsive material with moderate thermostability.