Device, system and manufacturing method for electronic strain sensor

A method of manufacturing a flexible and stretchable strain sensor, the method comprising:

• printing a generally elongate electrode layer with an Ag-containing conductive ink onto a substrate, the substrate comprising a thermoplastic ester-based polyurethane film of a thickness ranging from about 50 μm to about 1000 μm and a melting point of above about 100° C., the electrode layer comprising a first and second electrode, each electrode having a head and tail portion, the head portions of the first and second electrode being interdigitated;
• printing a sensing layer directly onto the interdigitated portion of the electrode layer, the sensing layer comprising a C-containing conductive ink;
• and encapsulating the electrode and sensing layers by applying a hot-melt layer comprising an ester-based polyurethane film of thickness ranging from about 10 μm to about 100 μm and a melting point below about 100° C.;
• wherein the sensor is configured such that:
• the application of external force to or near the sensor generates microscopic cracks within the sensing layer, thereby increasing electrical resistance of the sensor, and
• the removal of the external force substantially eliminates the microscopic cracks within the sensing layer, thereby decreasing electrical resistance of the sensor.

A flexible and stretchable strain sensor comprising:

• an electrode layer printed on a substrate, the electrode layer comprising a first conductive ink;
• a sensing layer printed on a portion of the electrode layer, the sensing layer comprising a second conductive ink;
• and
• an encapsulation layer which encapsulates the electrode layer and the sensing layer,
• wherein the first conductive ink exhibits a sheet resistance less than that of the second conductive ink,
• wherein the sensing layer is in direct contact with the electrode layer,
• wherein the electrode layer, the substrate, first conductive ink, the second conductive ink and/or the encapsulation layer have elastomeric properties, and
• wherein the sensor is configured such that an application of external force to or near the sensor generates microscopic cracks within the sensing layer increasing electrical resistance of the sensor, and the removal of the external force substantially eliminates the microscopic cracks within the sensing layer decreasing electrical resistance of the sensor.