Fast mechanochemical synthesis of carbon nanotube-polyaniline hybrid materials
- PDF / 576,671 Bytes
- 10 Pages / 584.957 x 782.986 pts Page_size
- 62 Downloads / 215 Views
ra I. Vega-Cantú and Fernando J. Rodríguez-Macíasa) Escuela de Ingeniería y Ciencias, Tecnologico de Monterrey, Monterrey, NL 64849, México; and Departamento de Química Fundamental, Universidade Federal de Pernambuco, Recife, PE, 50740-570, Brasil (Received 7 December 2017; accepted 5 March 2018)
We present a fast method to prepare hybrid materials of polyaniline (PAni) with carbon nanotubes (CNTs, both undoped and nitrogen-doped) by ball milling without solvents or strong oxidants. PAni forms nanoparticles, attached to CNTs in a nanocomposite structure, with the nanotubes well dispersed among the polymer. This is achieved with only a few minutes of ball milling. Raman spectroscopy confirms that PAni was synthesized in its conductive state and suggests a good CNT–PAni interaction, particularly with nitrogen-doped CNTs. We found that water increased polymer yield, which we optimized, together with the nanocomposite conductivity, as function of amount of water and of oxidant (FeCl3). The nanocomposite conductivity is four orders of magnitude higher than that of PAni, for both types of nanotubes. Scanning electron microscopy and X-ray diffraction both show negligible damage to the CNT during this mechanosynthesis procedure, while dry milling and milling CNT in water without aniline does damage nanotubes, indicating that the reaction absorbs most of the mechanical energy. I. INTRODUCTION
Carbon nanotubes (CNTs) are of great interest for multifunctional reinforcement of polymer composites, as well as many other applications, including several already in the market,1 due to their extraordinary properties such as high Young’s modulus, good flexibility, and high electrical and thermal conductivities. A variety of reviews summarize the extent of the basic work, the advances, and challenges, as well as commercial applications of polymer nanotube composites.2,3 Polyaniline (PAni) composites are of particular interest since this conducting polymer shows good processability, outstanding environmental stability, and its electrical conductivity can be modified by doping via acid–base reactions and electrochemistry, which make a variety of applications possible.4,5 Both single-walled CNTs and multi-walled CNTs (MWCNTs) can improve the mechanical properties as well as enhance further the high electrical conductivity of PAni.6–8 For example, CNTs have been used to improve the electrical properties of battery electrodes,9 the electrochemical performance of supercapacitors,10,11 and the mechanical and electrical properties of actuators.12
Contributing Editor: Sarah Morgan a) Address all correspondence to this author. e-mail: [email protected], [email protected] DOI: 10.1557/jmr.2018.56
Electrochemical oxidative polymerization of aniline is a classical route for PAni but is limited to film deposition.5 For larger scale synthesis, a chemical polymerization route, with the monomer oxidized in solution, typically using ammonium persulfate (APS), can be used. This route can produce PAni nanostructures under specific conditions.13–
Data Loading...
