Artificially Weaved Textile‐like Surface Micromachined Graphene‐Polymer Flexible Bioelectrodes

Abstract Dry, flexible, and self‐adhesive sensors are critical enablers for wearable, long‐term biosignal recording devices. Here, an ultra‐thin, flexible textile‐like microstructured electrode with self‐adhesive abilities is presented for conformal attachment and long‐term electrocardiography (ECG) recording. The reported electrode is manufactured using a spin‐coatable and electron‐beam sensitive formulation of poly (methyl methacrylate) (PMMA) resist, also commonly known as acrylic, which is at the same time a widely‐employed material in the textile industry. The textile‐like structure of the bioelectrodes with a linewidth of 100 µm and gap size of 100 µm is achieved by patterning PMMA through oxygen plasma and a hard mask layer without requiring complex and expensive e‐beam lithography (EBL) processes. Graphene oxide (GO) is introduced to the electrodes as active material followed by a reduction step using eco‐friendly pure vitamin C (L‐ascorbic acid). The functionality of the reported electrodes is benchmarked against pre‐gelled wet Ag/AgCl electrodes, comparing their signal quality and skin‐electrode impedance, and achieving a correlation score of 98.84%. Furthermore, it is demonstrated that the electrodes are flexible, water resistant, and can be used multiple times; rendering them suitable for wearable electronics purposes even during intense physical activities both in dry and wet environments.