- Mar 2021
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(A) Optical image of the undeformed device (left) and the FEA model for simulation (right). Optical images and max principal strain contours of the multifunctional wearable electronics being uniaxially stretched by 60% along vertical direction (B), along horizontal direction (C), and being biaxially stretched by 30% (D). (E) ECG data of the same device under different deformation modes. Photo credit: Chuanqian Shi, University of Colorado, Boulder.
(A) Model of the device without any stress/strain (left) and Finite element analysis model of the wearable device, not deformed (right). The model to the right exhibits the components inside the device. (B-C) The model shown being stretched 60%, vertically and horizontally respectively, show the maximum strain of the chip being 0.01%. This is much less than the normal failure strain for silicon (1%). (D) This figure shows the FMEA model being stretched 30% vertically and horizontally. The maximum strain in the chip components is below 0.004%. (E) Figure shows sensing performance of device when being stretched using an ECG. No significant effects from the mechanical stretching where evident in the results.
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- Feb 2021
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(A) Schematic illustration of the fabrication processes of the multifunctional wearable electronics. (B) Motion tracking performance with the multifunctional device worn on the wrist. (C) Indoor and outdoor body temperatures acquired using the wearable electronics mounted on the forehead (top) and comparison of measured indoor body temperatures when the wearable electronics is mounted at different locations (bottom). (D) Acoustic data acquired using the wearable electronics mounted on the neck. (E) ECG data acquired using the wearable electronics when the participant is at rest (top), and after exercising for 13 s (middle) and 34 s (bottom). Photo credit: Chuanqian Shi, University of Colorado, Boulder.
(A) Step-by-step process of each layer of the device to allow multiple functionalities and wearability. (B) Amplitude vs. Time graph of sensor worn on the wrist to measure motion when walking, running, jumping. (C) Thermal sensor can read forehead, abdomen, and hand temperature on skin when indoor and outdoor over time. (D) The acoustic sensor is placed on the neck to measure the amplitude (vibration) characteristics of the vocal chords to serve as a human-machine interface. (E) The electrocardiogram sensor measures heart activity while resting, after exercising for 13 seconds and then after 34 seconds. The heart rate resulted in 72, 96, and 114 per minute, respectively.
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(A) Schematic illustration of a multifunctional wearable electronic system mounted on the hand, which integrates ECG, acoustic, motion, and temperature sensing capabilities. (B) Exploded view of the multifunctional wearable electronics. (C) Optical images of the multifunctional device being crumpled on the skin, bended, twisted, and stretched. (D) Schematic illustration of the dynamic covalent thermoset polyimine: polymerization and depolymerization and bond exchange reaction induced bond breaking and reforming. (E) Schematic illustration of self-healing and recycling of the multifunctional wearable electronics.
The sensing components of the device being worn on the hand are ECG, acoustic, motion, and temperature sensors. It incorporates an electrocardiogram to measure heart activity using amplifiers and resistors to calculate the voltage versus time using electrodes placed on the skin. Assembling the sensors with EGaIn alloy to connect the sensor electronics and polyimine films allows the device to possess its’ flexibility and stretchability. Using polyimine allows for the breaking and reforming of bonds to allow self-healing, and polymerization and depolymerization to recycle the product.
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