Confinement Behavior And Energy Storage Properties Of Polymer Materials In Carbon Nanotubes Arrays

With the continuous miniaturization of functional devices,the nano-confinement effect began to show an increasing and important role.In a nanometer-sized space,polymers often exhibited different properties from their bulk state,such as abnormal chain mobility and crystal transition behavior.These properties are of great significance for the research and development of new polymer materials.Therefore,the physical and chemical properties of polymers in confined environments have always been attractive in the polymer community.In this paper,we fabricated a vertically aligned multi-walled carbon nanotube arrays by chemical vapor deposition(CVD).By solvent wetting-shrinking method,we obtained a high-density arrays structure.The aligned carbon nanotube gap formed a quasi-one-dimensional confined nanospace with the adjustable size of 5-50 nm.We further fill conjugated polymers(9,9-dioctyl fluorene-2,7-diyl)(PFO)into the nano-space of carbon nanotube gaps and obtain PFO/CNT arrays composite film.We found that in the nano-confined space of carbon nanotubes,the chain mobility of PFO molecules is significantly suppressed compared with the spin-coated bulk PFO film.The transition speed between different crystal forms declines greatly,which enhancesthe thermal stability of P conformation of PFO.Additionally,the aligned carbon nanotubes have obvious effects on the orientation and distribution of PFO molecular chains,which is potentially beneficial to obtain PFO crystals with high performance.Such a high density aligned carbon nanotube arrays structure can thus be used to prepare PFO photovoltaic devices with excellent luminescent properties and high stability in the future.Besides the investigation on the restricted segment motion and crystallization behavior of the polymer in the carbon nanotube gaps,we also investigated the confined thermal decomposition behaviors of the polymer in the intercalated carbon tube gaps as well as the electrochemical energy storage properties of the carbonized product.In order to improve the energy storage properties of the supercapacitor,people always selected an electrochemically active material as an electrode material,increased the specific surface area,regulated the pore structure,and used a redox-active electrolyte.A general method is to pyrolyzed carbon-containing organic species to obtain a porous carbon material,and to controled the pore structure by adding a porogen.We filled the phenolic resin(PF)into the space of the aligned carbon nanotubes(ACNTs)and carbon nanotube sponges gap by solution wetting-shrink method to prepared S-ACNTs/PF and CNT-S/PF samples.Then we obtained high graphitized products in the tube gaps by high temperature carbonization.We found that aligned carbon nanotubes are beneficial to the graphitization of phenolic resin,which not only reduced the thermal decomposition rate,but also obtained higher specific surface area and more regular pore structure.Compared with pure phenolic resin and random carbon tube/phenolic resin blends,they have better electrochemical energy storage properties.In addition,we also prepared a three-dimensional carbon nanotube sponges(CNT-S)and phenolic resin composite products for comparasion,which also showed excellent electrochemical energy storage properties.