Multifunctional PET/PANI Fabrics: Crosslinking, Copper Deposition and EMI Shielding
Rohan Meshram, Asfiya Q. Contractor, Amol G. Thite, Srishti Tewari, Ravindra D. KaleIntroduction:
Copper (Cu) was deposited on polyaniline (PANI)-coated polyester (PET) fabric using the electroless deposition method, and dimethylol dihydroxyethylene urea (DMDHEU) was used as a crosslinking agent. Hydrochloric acid (HCl) was used as a dopant for the in situ chemical polymerisation of PANI in the presence of ammonium persulphate (APS). Thereafter, DMDHEU was applied to improve durability and promote Cu deposition for electromagnetic interference (EMI) shielding on PANI-coated fabric.
Methods:
Both composite fabrics, PANI- and PANI/DMDHEU-crosslinked samples, were prepared for Cu deposition. The treated samples were evaluated for various parameters, including tensile strength, bending length, surface resistance, EMI shielding effectiveness (SE), scanning electron microscopy with energy dispersive analysis of X-rays (SEM-EDX), and crease recovery angle (CRA).
Results:
All treated samples showed a decrease in tensile strength as compared to the untreated fabrics, whereas the EMI SE increased with each stage of treatment. The surface morphology of the samples was identified through SEM analysis, and Cu deposition was verified by EDX, which showed that Cu covered 45% of the fabric surface. The tensile strength decreased by about 9 to 10.5%. The CRA was used to evaluate the balance between flexibility and stiffness in the treated EMI shielding fabrics.
Discussion:
Folding the fabric created a multi-layered structure that increased its thickness and enabled it to improve the reflection and absorption of incident electromagnetic (EM) radiation, thereby enhancing the EMI shielding efficiency.
Conclusion:
PET fabrics coated with PANI, PANI/DMDHEU, and their corresponding Cu electroless deposited samples exhibited around 34 dB EMI shielding with stable resistivity after five washes. With an increase in the number of foldings, EMI SE reached up to 50 dB. FTIR analysis was performed on PANI- and PANI/DMDHEU-treated fabric samples, while physical properties like tensile strength, CRA, and bending length were determined for both treated and untreated fabrics. These results indicate the suitability of this fabric for lightweight and flexible EMI shielding applications.