Microflotronics: A Flexible, Transparent, Pressure‐Sensitive Microfluidic Film

Abstract

There is an increasing demand for sensitive, flexible, and low‐cost pressure sensing solutions for health monitoring, wearable sensing, robotic and prosthetic applications. Here, the first flexible and pressure‐sensitive microfluidic film is reported, referred to as a microflotronic, with high transparency and seamless integratability with the state‐of‐the‐art microelectronics. The microflotronic film represents the initial effort to utilize a continuous microfluidic layer as the sensing elements for large‐area dynamic pressure mapping applications, and meanwhile an ultrahigh sensitivity of 0.45 kPa−1 has been achieved in a compact, flexible, and transparent packaging. The response time of the device is in the millisecond range, which is at least an order of magnitude faster than that of its conventional flexible solid‐state counterparts. In addition, the fabrication process of the device is fully compatible with the industrial‐scale manufacturing of capacitive touchscreen devices and liquid‐crystal displays. The overall device packaging can be as thin as 200 μm with an optical transparency greater than 80%. Several practical applications were successfully demonstrated, including surface topology mapping and dynamic blood pressure monitoring. The microflotronic devices offer an alternative approach to the solid‐state pressure sensors, by offering an unprecedented sensitivity and ultrafast response time in a completely transparent, flexible and adaptive platform.

Monitoring of Vital Signs with Flexible and Wearable Medical Devices

“…[ 39,[70][71][72][73][74][75] These novel pressure sensors are typically in the form factor of capacitors, which use either a compressible dielectric to induce a change in capacitance or a piezoelectric dielectric to induce a voltage across the device. The signal from the capacitive elements are either amplifi ed by an external instrument or a monolithically integrated device on the same substrate, typically a thin fi lm transistor (TFT).…”

Emerging flexible and wearable physical sensing platforms for healthcare and biomedical applications

“…Generally, liquid-state sensors adopt a microfluidics-based device configuration to confine conductive liquids within soft elastomeric substratebased templates. Microfluidics-based sensor technology has seen rapid progress in an array of applications, particularly in numerous chemical and biological assays, owing to the unique advantages it offers, such as high device sensitivity and adaptability, minute sample quantity, low power requirements, and low fabrication costs 19,102,103 . Employing only a small volume of working fluid, an external load may be detected and quantified based on the variations in the electrical parameters of the device.…”

“…Flexible materials provide an excellent degree of deformability and conformability on surfaces with various topologies and geometries 19 . This unique characteristic renders them attractive base materials for physical sensors.…”

Photopatternable PEDOT:PSS/PEG hybrid thin film with moisture stability and sensitivity

“…With increasing awareness and demands regarding personalized health care, wearable sensors have been extensively investigated in recent years, for which electrical conductance, mechanical flexibility, chemical stability, optical transparency, and biocompatibility are all required [52][53][54][55][56] . The conductive PEDOT:PSS film has proven to be a candidate material for such wearable applications 57,58 .…”