Facile Synthesis and Optimization of Conductive Copolymer Nanoparticles and Nanocomposite Films from Aniline with Sulfodiphenylamine

Abstract

A new series of electrically conductive pure copolymer nanoparticles was facilely synthesized by using oxidative polymerization of aniline (AN) and sodium diphenylamine-4-sulfonate (SDP) in acidic media in the absence of stabilizer. The variation of the structure of the copolymer particles was comprehensively studied by carefully choosing several important parameters, such as the comonomer ratio, oxidant/monomer ratio, polymerization time and temperature, monomer concentration, acidic medium, and oxidant species. Analytical techniques used include IR and UV-visible spectroscopy, X-ray diffraction, laser particle analysis, atomic force microscopy, and transmission electron microscopy. It was found that the particle size varied significantly with the above-mentioned polymerization parameters, only changes in the salt concentration in the aqueous testing solution had no noticeable effect. The polymerization conditions were optimized for the formation of copolymer nanoparticles with sought-after properties. The doped copolymer particles of AN/SDP (50:50) at an oxidant/monomer molar ratio of 0.5 exhibit a minimum length of 50 nm and a minimum diameter of 44 nm. The bulk electrical conductivity of the copolymer particles increases greatly from 5.90x10(-4) to 1.15x10(-2) S cm(-1) with increasing AN content. Compared with barely soluble polyaniline, the copolymers exhibit a remarkably enhanced solubility in most solvents, including NH4OH and even water, due to the presence of the hydrophilic sulfonic groups. Nanocomposite films of the nanoparticles and cellulose diacetate exhibit a percolation threshold of down to 0.1 wt %, at which the film retains 98% of the transparency, 94% of the strength, and 5x10(7) times the conductivity of a pure cellulose diacetate film.

Synthesis of PEDOT Nanoparticles and Vesicles by Dispersion Polymerization in Alcoholic Media

“…In contrast to data obtained with [(NH 4 ) 2 S 2 O 8 ] as an oxidant, use of high reaction temperature (85 8C) allowed us to prepare PEDOT latex in high yield (80%) (runs [12][13][14]16) in the presence of Fe(III)(OTs) 3 Á 6(H 2 O) after 48 h reaction time (methanol/water, 3/2). In this case the reaction temperature was found crucial since the polymerization does not take place at room temperature (run 15).…”

“…For instance, aqueous dispersions of conjugated polymers have been prepared by chemical oxidative polymerization of the corresponding monomers such as pyrrole or aniline in the presence of suitable water-soluble steric stabilizers. [5][6][7][8][9][10][11][12][13] Among conjugated conductive polymers, poly(3,4-ethylenedioxythiophene) (PEDOT) has more recently attracted specific attention because of its excellent environmental stability, its low oxidation potential and low band gap as well as its good and stable electrochromic behavior from blue to transparent in neutral and oxidized states, respectively. [14,15] The synthesis of stable PEDOT dispersions in water with the help of polystyrene-sulfonic acid was described but the authors did not give any data about the morphology of PEDOT material.…”

Facile High‐Yield Synthesis of Polyaniline Nanosticks with Intrinsic Stability and Electrical Conductivity

“…A typical procedure for the preparation of nanostructured PAN in 2 m HNO 3 as acidic polymerization medium follows (Scheme 1): [10,11,14,24] Aqueous HNO 3 solution (2.0 m, 80 mL) was added with AN (0.91 mL, 10 mmol) to a 250 mL glass flask in water bath at 15 8C and the mixture stirred vigorously for one hour. Ammonium persulfate (2.28 g, 10 mmol) was dissolved separately in HNO 3 (2.0 m, 20 mL) to prepare an oxidant solution that was kept in the same water bath.…”

“…Copolymerization has been used to prepare nanostructured aniline copolymers by a template-free method that introduces functional groups such as SO 3 À in comonomers. [10][11] Electrically conductive copolymer nanoparticles Abstract: Chemical oxidative polymerization at 15 8C was used for the simple and productive synthesis of polyaniline (PAN) nanosticks. The effect of polymerization media on the yield, size, stability, and electrical conductivity of the PAN nanosticks was studied by changing the concentration and nature of the acid medium and oxidant and by introducing organic solvent.…”

“…Obviously, the size distribution of PAN nanoparticles fabricated in HCl is extremely narrow and even more uniform than that of an AN copolymer. [10,11] The pres- ence of the organic solvent CH 3 NO 2 in the polymerization medium is not advantageous for formation of PAN nanostructures because they have larger D n despite their lower D w /D n ( Table 2). Note that the LPA data were statistically treated by an equivalent-sphere model, and LPA is used here mainly to reveal the size distribution of nanosticks with relatively small aspect ratio.…”