Incorporating pre-stretching into electroless copper plating for conductivity improvement of elastic nylon fabric: application in ECG electrode

• Published in: Journal of materials science. Materials in electronics 2024-05, Vol.35 (14), p.942, Article 942
• Main Authors: Pan, Youshi, Lu, GuangJun, Su, Jiande, Zou, Huahong, Li, Hansong
• Format: Article
• Language: English
• Subjects: Characterization and Evaluation of Materials; Chemistry and Materials Science; Copper; Copper plating; Electrical resistivity; Electrodes; Electroless copper plating; Electroless plating; Low temperature; Materials Science; Monitoring; Nylon; Optical and Electronic Materials; Stretching; Warp; Waveforms; Weft
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-024-12538-z

A preparation method of electroless copper electrodes based on elastic nylon fabric for ECG monitoring is proposed to meet the key needs of monitoring accuracy and wearing comfort in this paper. There were 72 rectangular nylon fabric samples involved in the experiment, and three key variables were introduced during the electrode preparation experiment, copper plating time, temperature, pre-stretching, where pre-stretching considered both warp and weft direction. The resistance of 72 samples at 30% stretch state was measured, SEM was used to characterize the copper plated fabric and copper plated fabric ECG electrodes were prepared and evaluated. According to the resistance statistics, the introduction of pre-stretching in the weft direction can bring better copper plating effects, and one sample (which was marked as D20/weft-1) showed the best electrical conductivity in the groups. Combined with SEM images, they all proved the success of copper plating on nylon fabric and that relatively low temperature and appropriate time are beneficial to copper plating. Simultaneously SEM inspection of MΩ-level high-resistance samples revealed that some of the copper plated particles were incompletely covered or peeled off. Finally, evaluating ECG waveforms and signal-to-noise ratios using fabric electrodes in natural and chest expansion state. Results showed that the fabric electrodes prepared from sample D20/weft-1 with excellent conductivity almost have the same performance as traditional Ag/AgCl electrodes. This study provides a cost-effective method and low-cost alternative for electrodes to record high-quality ECG both at home and in the clinic.