Semi-Crystalline Polyaniline with an Enhanced Conductivity Synthesized with a Novel Binary Dopant Sulfonic Acid-Surfactant: Mechanical, Electrical and Shielding Performances of Nylon/PANI Conductive Fabrics at 9.45 GHz

Abstract

Aniline was doped by a novel binary dopant agent, sulfonic acid-surfactant. Naphthalene disulfonic acid (NDSA) and an anionic surfactant (sodium dodecyl sulfate, SDS) were used to form the binary dopant agent; synthesis of the doped PANI was accomplished by using ammonium peroxydisulfate (APS) as the oxidant via a hybrid microemulsion polymerization at various temperatures (–10, 0, 20, and 40 °C). The synthesized polyaniline (PANI-NDSA-SDS) salts were characterized by Fourier transform infrared, UV-visible and Raman spectroscopy, X-ray diffraction, scanning electron microscopy (SEM), the electrical properties were determined using a four-point probe method, and the mechanical properties of the fabric samples were also studied. The PANI-NDSA-SDS salts showed a semi-crystalline structure with nanostructure morphology. Among the four polyaniline salts, the PANI-NDSA-SDS prepared at 20 °C showed higher values of conductivity and polymerization yield. In this study, this polyaniline salt was used as coating materials for preparation of conductive Nylon fabrics. As a result, the tensile strength increased by 15%, from 27.21 to 31.42 MPa. Higher electrical performance was obtained for the Nylon/polyaniline composites, 128–724 ohm/square; thus, for electromagnetic shielding applications, the conducting polyaniline coated Nylon fabrics can be used as a shield material for the control of electromagnetic interference at 9.45 GHz, the frequency of the instrument used for the measurements. The conducting fabrics showed an electromagnetic interference value between 20.09 and 34.44 dB.

Keywords:

• conductive Nylon fabrics
• crystallinity
• electromagnetic interference shielding
• polyaniline
• polymerization temperature
• sulfonic acid- sodium dodecyl sulfate

Acknowledgements

The authors are thankful to the Directorate General for Scientific Research and Technological Development (Algeria) for its support through providing chemicals products. The authors also thank Mr. Mohamed Ghazal and Mr. Ahcene Sehaki of Physical Laboratory/National Preparatory School for Engineering Studies (Algiers) for recording the measurements of shielding effectiveness at 9.45 GHz, between April and May 2020.

Conflicts of interest

The authors declare no conflicts of interest.

Additional information

Funding

Support of this research by the Ecole Militaire Polytechnique, Algeria through project N°250/2018/DRFPG/CMDT is gratefully acknowledged.