Surface electromyography (sEMG) is one of the most commonly used non-invasive detection tools in rehabilitation assessment and motor function monitoring. However, clinicians and researchers face a recurring dilemma: although the traditional Ag/AgCl wet electrode has low contact impedance and reliable signal, it relies on conductive gel to maintain the interface continuity. The gel will dry up over time, leading to signal deterioration, and long-term adhesion may cause skin irritation and even inflammation. The limitations of wet electrodes are particularly prominent in scenarios that require continuous monitoring for hours or even days.

Dry flexible electrodes are becoming a recognized technological direction in the industry. It does not need conductive gel, and can directly contact with the skin to collect signals. It has the core advantages of non irritation, long-term wear, and reuse. The global market sales of dry electrode electromyography sensors have reached 17.35 million US dollars by 2025, and are expected to reach 25.34 million US dollars by 2031, with a compound annual growth rate of 6.5%. The sales proportion of dry electrode modules has jumped to 44.2% in 2025. In this technological transformation from "wet" to "dry", the electrode coating process - depositing functional conductive layers on the surface of flexible polymer substrates - is the core link that determines electrode performance.

2、 Core technical requirements for sEMG electrode coating

The coating layer of flexible sEMG electrode needs to meet the requirements of quadruple engineering at the same time:

3、 Gold Plated Electrode - Optimal Selection for Low Impedance and High Signal to Noise Ratio

Gold (Au) has become one of the preferred materials for flexible sEMG electrode coating due to its excellent conductivity, chemical stability, and biocompatibility. Gold does not corrode or release toxic ions in physiological environments, and its chemical inertness endows gold-plated electrodes with excellent corrosion resistance, making them suitable for long-term skin contact and even implantation scenarios.

4、 Silver plated/silver chloride electrode - standard protocol for clinical sEMG

Silver/silver chloride (Ag/AgCl) is the most common material system in biopotential electrodes and dominates clinical sEMG records. Ag/AgCl electrodes have low polarization potential and excellent electrochemical stability, typically achieved by electrochemically depositing a thin layer of silver chloride on a silver electrode.

Applicable scenarios:In clinical short-term diagnosis and disposable scenarios, Ag/AgCl electrodes are an irreplaceable standard solution. It is recommended to choose gold plating or platinum plating for long-term repeated use scenarios.

5、 Platinum plated electrode - guarantee of high precision and long-term application

Platinum plated (Pt) electrodes exhibit excellent performance in high-precision signal acquisition and long-term application scenarios due to their low resistivity characteristics.

Unique advantages:In scenarios that require dual-mode electrical stimulation and recording, platinum electrodes have unique advantages due to their excellent electrocatalytic activity and charge injection capability.

6、 Comparison and selection of three coating schemes

7、 Advanced Institute Technology's sEMG Electrode Coating Solution

Advanced Institute (Shenzhen) Technology Co., Ltd. (referred to as "Advanced Institute Technology") was established in 2016 and is a national high-tech enterprise specializing in shielding materials, insulation materials, thermal conductivity materials, and precious metal coatings. The company owns the independently registered trademark "Yanbo" and has passed ISO9001 quality management system certification.

In the field of coating technology, the company has independently built magnetron sputtering and vacuum evaporation production lines, using roll to roll continuous production technology, which can continuously deposit metal layers on the surface of flexible polymer films. Suitable substrates include various flexible materials such as FEP, PI, PET, LCP, PPS, PEN, PP, etc., and can be plated with metals including gold, silver, copper, aluminum, tin, nickel, titanium, platinum, etc. Relying on advanced physical vapor deposition (PVD) technology, the company has achieved nanometer level precise control of metal thin films on the substrate surface, with thickness ranging from a few nanometers to several hundred nanometers, ensuring extremely high uniformity and density.

Core competencies:Provide multiple options for gold plating, silver plating, and platinum plating for flexible sEMG electrodes, supporting various flexible substrates such as PI, PET, FEP, etc., with precise control of coating thickness at the nanometer level.

8、 Typical application scenarios

9、 Conclusion

The performance of surface electromyography electrodes largely depends on the selection of coating materials and processes. Gold provides the "gold standard" of chemical inertness and low impedance, silver/silver chloride provides the "standard solution" of clinical maturity and cost control, and platinum provides the "platinum quality" of extremely low resistance and long-term stability. There is no absolute 'best' among the three, only 'most suitable'.

From short-term monitoring of clinical diagnosis to long-term wearing of wearable devices, from single channel signal acquisition to high-density electrode arrays - surface electromyography electrodes are bringing electromyographic signal acquisition from hospitals to homes, from static to dynamic. In this technological evolution, the selection of coating materials and precision machining processes have always been the core variables that determine the upper limit of electrode performance.