tailieunhanh - Báo cáo hóa học: "Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube/poly(vinylidene fluoride) composites | Carabineiro et al. Nanoscale Research Letters 2011 6 302 http content 6 1 302 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Effect of the carbon nanotube surface characteristics on the conductivity and dielectric constant of carbon nanotube poly vinylidene fluoride composites -C AZ-Z- 1 1 2 Z- 2 2 Sónia AC Carabineiro Manuel FR Pereira João N Pereira Cristina Caparros Vitor Sencadas and Senentxu Lanceros-Mendez 1 2 Abstract Commercial multi-walled carbon nanotubes CNT were functionalized by oxidation with HNO3 to introduce oxygen-containing surface groups and by thermal treatments at different temperatures for their selective removal. The obtained samples were characterized by adsorption of N2 at -196 C temperature-programmed desorption and determination of pH at the point of zero charge. CNT poly vinylidene fluoride composites were prepared using the above CNT samples with different filler fractions up to 1 wt . It was found that oxidation reduced composite conductivity for a given concentration shifted the percolation threshold to higher concentrations and had no significant effect in the dielectric response. Introduction Carbon nanotubes CNTs have attracted particular interest because of their remarkable mechanical and electrical properties 1 . The combination of these properties with very low densities suggests that CNTs are ideal candidates for high-performance polymer composites 2 . In order to increase the application range of polymers highly conductive nanoscale fillers can be incorporated into the polymeric matrix. As CNTs present high electrical conductivity 103-104 S cm they have been widely used 3 . Therefore CNT polymer composites are expected to have several important applications namely in the field of sensors and actuators 4 . However in order to properly tailor the composite material properties for specific applications the relevant conduction mechanisms must be better understood. .