Synthesis and characterization of novel conductive and magnetic nano-composites

doi:10.1016/j.jallcom.2010.03.124

Journal of Alloys and Compounds

Volume 499, Issue 1, 4 June 2010, Pages 98-103

https://doi.org/10.1016/j.jallcom.2010.03.124 Get rights and content

Abstract

In the last years, a great deal of attention has been paid to use nano-sized ferrites as advanced additives in conducting polymers. The embedding of the ferrite materials into polymeric matrices is the simplest way to take advantage of some novel physical characteristics. In the present work, the preparation of a polyaniline/Co_1−xMg_xFe₂O₄ nano-composite (x = 0, 0.5, 1) with good magnetic and electrical properties was described. The structure, morphologies and properties of the samples were characterized by XRD, FT-IR, TEM, TGA, VSM and conductivity measurements. Nano-particles appear well dispersed in the polymer matrix and the results of TGA indicated that the ferrite nano-particles could improve the composite thermal stability. The electrical conductivity of the pure polyaniline decreased while the saturation magnetization (M_s) and coercivity (H_c) increased with ferrite. The ability of the composites to remove the toxic dyes from waste water was investigated.

Introduction

Polymer nano-composites synthesis is a hybridization process between polymer matrices and nano-particles. The main idea in a composite is to integrate several component materials and their properties in a single material. As a result, considerable efforts currently have been directed by many researchers towards the conducting polymer nano-composites because of their unique properties, as well as their well applicable multi-functionality in various fields [1]. Polyaniline (PANI) is a conducting polymer so it has many potential applications in various fields such as electrical-magnetic shields, microwave absorbing materials, batteries, sensors and corrosion protections [2], [3], [4], [5], [6], [7], [8], [9], [10]. The development of the PANI properties has received considerable attention lately. The fabrication of PANI/ferrite nano-composite has been reported by using different methods such as in situ polymerization of aniline in the presence of Zn_0.6Cu_0.4Cr_0.5Fe_1.5O₄ nano-particles [11], micro-emulsion process used to prepare PANI/NiZn ferrite nano-composite [12] and oxidative electro-polymerization of aniline in an aqueous solution in the presence of MnZn ferrite and NiMnZn ferrite [13], these studies created organic materials possessing both conducting and ferromagnetic functions.

The electromagnetic measurements of the PANI/ferrites were improved and tailored by controlling the addition of the ferrite in the composite [14], [15]. Also, the contribution of ferrite to the PANI led to an increase in its thermal stability, however, it decreased its electrical conductivity [16], [17], [18]. Jiang et al. introduced a novel poly(aniline-co-o-toluidine)/BaFe₁₂O₁₉ composite [19], which was successfully synthesized by a facile, general and inexpensive in situ polymerization method. Ting et al. had reported the microwave absorption of the PANI/BaFe₁₂O₁₉ [20] and noticed that Microwave absorbing properties can be modulated simply by controlling the content of PANI on the samples for the required frequency bands. Another new routes for synthesizing the PANI nano-composites, hollow Fe₃O₄–PANI spheres with uniform cavity size and shell thickness suggested [21], PANI nanotubes containing Fe₃O₄ nano-particles synthesized under ultrasonic irradiation [22] where the Fe₃O₄ nano-particles embedded in PANI nanotubes. The PANI nano-composites focus not only on ferrites but they extended to other materials such as titanium dioxide, zinc oxide, manganese oxide, vanadium pentaoxide, clinoptilolite, nafion, carbon nanotubes and silicon [23], [24], [25], [26], [27], [28], [29], [30].

In this work, an approach was reported to synthesize the PANI/Co_1−xMg_xFe₂O₄ nano-composites (x = 0, 0.5, 1) by in situ polymerization of aniline with Co_1−xMg_xFe₂O₄ particles. The obtained composite was characterized by various experimental techniques. The removal of the pollutants from waste water by using the PANI/ferrite nano-composites was investigated. The electrical conductivity of the pure polyaniline, the saturation magnetization (M_s) and coercivity (H_c) were measured and found to be affected dramatically with ferrite addition. The ability of the composites to remove the toxic dyes from waste water was also investigated.

Section snippets

Preparation of Co_1−xMg_xFe₂O₄

Co_1−xMg_xFe₂O₄ (x = 0, 0.5, 1) nano-particles were prepared by mixing a solution of Co(NO₃)₂·6H₂O, Mg(NO₃)₂·6H₂O and Fe(NO₃)₃·9H₂O in stoichiometric ratio with a solution containing NaOH + Na₂CO₃ [31], [32] ([NaOH] = 1.6[Mg²⁺ + Co²⁺ + Fe³⁺], [CO₃²⁻] = 2.0[Fe³⁺]) in de-ionized water (pH ≈ 9). The solutions simultaneously added to a colloid mill [33], [34] and mixed for 2 min. The resulting slurry was placed in a three neck flask and aged at 100 °C for 6 h. The final precipitate was filtered, washed thoroughly

X-ray diffraction of Co_1−xMg_xFe₂O₄

The room temperature powder XRD patterns of as-prepared Co_1−xMg_xFe₂O₄ ferrite particles are shown in Fig. 1. The well resolved broad diffraction peaks corresponding to (2 2 0), (3 1 1), (2 2 2), (4 0 0), (4 2 2), (5 1 1) and (4 4 0) reflection planes show that all the ferrites have attained single phase, all the peaks can be indexed to a single phase spinel structure. The crystal sizes (L) of the Co_1−xMg_xFe₂O₄ ferrite are 115, 94 and 33 nm for x = 0, 0.5 and 1, respectively. The values of lattice parameters of

Conclusions

The pure PANI and PANI/Co_1−xMg_xFe₂O₄ (x = 0, 0.5, 1) composites have been prepared by chemical oxidative method in the presence of aniline and Co_1−xMg_xFe₂O₄ by ammonium peroxydisulphate oxidant in HCl medium. The obtained data shows that there is an interaction between the ferrite and PANI in the obtained composites which have core-shell structure, the presence of the ferrites with the PANI increases the thermal stability of the PANI. The magnetic properties of PANI were improved by adding the

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Synthesis and characterization of novel conductive and magnetic nano-composites

Abstract

Introduction

Section snippets

Preparation of Co1−xMgxFe2O4

X-ray diffraction of Co1−xMgxFe2O4

Conclusions

Electrochim. Acta

Curr. Appl. Phys.

Microelectron. J.

Acta Mater.

J. Membr. Sci.

Talanta

Anal. Chim. Acta

Talanta

Biosens. Bioelectron.

Prog. Org. Coat.

React. Funct. Polym.

Colloids Surf. A: Physicochem. Eng. Aspects

J. Alloys Compd.

Mater. Lett.

Synth. Met.

Mater. Sci. Eng. A

Synth. Met.

Mater. Lett.

React. Funct. Polym.

J. Solid State Chem.

J. Alloys Compd.

J. Alloys Compd.

Preparation of Co_1−xMg_xFe₂O₄

X-ray diffraction of Co_1−xMg_xFe₂O₄