Development of flexible strain sensors that can be attached directly onto the skin, such as skin-mountable or wearable electronic devices, has recently attracted attention.However, such flexible sensors are generally exposed to various harsh environments, such as sweat, humidity, anal-vibrators or dust, which cause noise and shorten the sensor lifetimes.This study reports the development of a nano-crack-based flexible sensor with mechanically, thermally, and chemically stable electrical characteristics in external environments using a novel one-step laser encapsulation (OLE) method optimized for thin films.The OLE process allows simultaneous patterning, cutting, and encapsulating of a device using laser cutting and thermoplastic polymers.The processes are simplified for economical and rapid production (one sensor in 8 s).
Unlike other encapsulation methods, OLE does not degrade the performance of the sensor because the sensing layers remain unaffected.Sensors protected with OLE exhibit mechanical, thermal, and chemical stability under water-, heat-, dust-, and detergent-exposed conditions.Finally, a waterproof, flexible strain sensor is developed to detect motions Pizza Stands around the eye, where oil and sweat are generated.OLE-based sensors can be used in several applications that are exposed to a large amount of foreign matter, such as humid or sweaty environments.