FIGURE 1.

(A) Fabrication process of the breathable Parylene C-based electrodes (with materials). The fabrication starts with the deposition of a PVA sacrificial layer onto the PET carrier (i); the Parylene C that acts as the substrate is deposited on the sacrificial layer through chemical vapor deposition (ii); deposition and patterning of the Ag electrode (iii); another layer of Parylene C, which acts as a passivation layer, is then deposited on the electrode with the exception of the connector and the recording regions (iv); the perforation is performed using a photolithographically patterned photoresist layer as a mask (v, vi,vii) to selectively remove Ag and Parylene C using a combination of wet etching (for the Ag) and plasma oxygen etching (for the Parylene C); after the perforation is complete, the photoresist is removed (viii) and the electrode is ready to be peeled-off and transferred to the paper. (B) Thickness of the three layers constituting the electrodes, namely the first Parylene C layer that acts as the substrate (i), the Ag layer (ii), and the Parylene C passivation layer (iii).