Hybrid Corona–Dielectric Barrier Discharge for Permethrin Polymerisation on Polyamide Fabric at Atmospheric Pressure

This work presents permethrin (15%)-based monomers polymerisation in polyamide fabrics using hybrid corona–dielectric barrier discharge (DBD) to potentiate insect–parasite repellency functionalities in polyamide fabrics. First of all, the electric characterisation of the discharge was made using the Lissajous figure method for determining the plasma dosage (2841 W min m −2 ). Before the polymerisation process, the polyamide fabric was activated by DBD discharge, operating at 23 kHz and voltage amplitude of 12.5 kV in atmospheric pressure. After that, the polymerisation process is initiated by injecting permethrin into the system, maintaining the operational parameters used in the activation process. The non-activated and activated polyamide fabrics measured the static and dynamic contact angle, showing a variation from 120° (non-activated) to 34° (immediately after plasma activation). The chemical structure of synthesised permethrin was evaluated by Fourier transformed infrared (FTIR) spectroscopy to confirm the polymerisation (deposition) of permethrin on the fabric surface; it is possible to observe the 648 cm −1 bands that are associated with asymmetric vibration of the C–Cl bonds, but most evident change occurs at 1045 cm −1 , which is associated with cyclopropyl group vibrations. Field emission scanning electron microscopy (FESEM) analysis was used to evaluate the possible degradation of the fabric surface when exposed to plasma activation and the homogeneity of the permethrin coating in the fibres after the polymerisation. The energy dispersive spectrometer (EDS) was used to confirm the polymerisation and the distribution of the permethrin in the fabric.