Flexible and stretchable electronic systems for epidermal electronics

A device for establishing an interface with a skin of a subject, the device comprising:

• a flexible substrate having an effective Young's modulus less than or equal to 10 MPa;
• a flexible electronic circuit supported by the flexible substrate, wherein the flexible electronic circuit comprises a plurality of electrophysiological sensors provided in an array;
• wherein each of said electrophysiological sensors independently comprises an inorganic thin film layer, an electrode thin film layer or a combination of these;
• including one or more inorganic semiconductor circuit elements or electrodes, or a combination of inorganic semiconductor circuit elements and electrodes, wherein the plurality of electrophysiological sensors are connected with filamentary serpentine wires;
• and
• a barrier layer encapsulating at least a portion of the flexible electronic circuit;
• wherein said barrier layer is a multilayer structure comprising a plurality of polymer layers;
• wherein said barrier layer provides an electrical, physical, chemical, and thermal barrier;
• said device having a multilayer geometry wherein said flexible substrate, said flexible electronic circuit and said barrier layer are provided as a series of stacked layers wherein said flexible electronic circuit is provided between said flexible substrate and said barrier layer;
• wherein the flexible substrate, barrier layer and the electronic circuit provide a net bending stiffness less than or equal to 1×108 GPa μm4 so as to allow for conformal contact to be established with the skin of the subject.