Laser direct micromilling of copper-based bioelectrode with surface microstructure array

• A novel dry bioelectrode is fabricated using laser direct micromilling technology.
• The forming process of surface microstructure array of bioelectrodes is discussed.
• The effect of process parameters on surface microstructure array is investigated.
• The optimized process parameters are obtained to fabricate cone microstructure array.
• Our developed copper-based bioelectrode shows better hydrophobic property.

The laser direct micromilling is proposed to fabricate the microstructure arrays on the surface of dry bioelectrodes using red copper material. Based on the principle of laser machining and SEM results, the forming process of microstructure arrays on the surface of copper-based bioelectrodes is discussed. When the process parameters are varied, the effect of process spacing, laser output power, scanning speed and number of scan on the morphology and geometrical dimension of microstructure array of bioelectrode is investigated. The results show that the cone surface microstructure can be fabricated when process spacing is set to 0.1 mm. Surface roughness of microstructure is greatly changed with different scanning speeds. The height of surface microstructure and recast layer is greatly increased with increasing laser output power. When smaller laser output power or less number of scan are selected, surface microstructure array is difficult to be fabricated. However, it is easy to generate the damage of surface microstructure when the larger output power or excessive scanning times are selected. Moreover, our developed copper-based bioelectrode shows a hydrophobic property when the spacings are selected in the range of 0.1–0.3 mm. Eventually, the optimized process parameters are obtained to fabricate the bioelectrode with cone microstructure array.