Flexible Hybrid Electronics: Direct Interfacing of Soft and Hard Electronics for Wearable Health Monitoring

Khan, Yasser; Garg, Mohit; Gui, Qiong; Schadt, Mark; Gaikwad, Abhinav M.; Han, Dongil; Yamamoto, Natasha A. D.; Hart, Paul; Welte, Robert; Wilson, William; Czarnecki, Steve; Poliks, Mark D.; Jin, Zhanpeng; Ghose, Kanad; Egitto, Frank D.; Turner, James N.; Arias, Ana Claudia

doi:10.1002/adfm.201603763

Cited by 263 publications

(195 citation statements)

References 27 publications

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“…[20][21][22][23] We demonstrate the development of a stable fully printed temperature sensor whereby the reliable performance of an NTC ceramic is combined with the flexibility and processability of a polymer binder. Until now, a reliable solution that maintains the advantages of ceramic NTC com ponents is lacking.…”

mentioning

confidence: 99%

Large‐Area All‐Printed Temperature Sensing Surfaces Using Novel Composite Thermistor Materials

Katerinopoulou

Zalar

Sweelssen

et al. 2018

Adv Elect Materials

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goal, a scalable process for realizing a large number of sensors over large areas with mechanical flexibility is necessary. Printed flexible and stretchable electronics envisage a drastic change in production methods, but more importantly how elec tronics are perceived and implemented. [7] In applications where thin, flexible, and stretchable properties are required, printed sensors detecting a multi tude of para meters represents an elegant solution. [8][9][10][11][12] Accurate measurement of tempera ture is of critical importance. Measuring temporal changes in temperature or spatial temperature gradients is exten sively used in industrial settings as well as for medical applications. Recently there is an increased interest in equipping complex surfaces and shapes with a large number of temperature sensors. [7,13,14] This requires a costefficient route to manufacture thermistor materials over large areas on flexi ble substrates.Thermocouples are the classical instru ment for measuring temperature, where changes in resistance of a metal is used to determine the temperature. The drawback of this method is the limited change in resistance (+0.1% °C −1 ) and the need to compensate for the cold junction temperature, making accurate measurements challenging, costly, and sensitive to artifacts. [15] Resistance temperature detectors (RTDs) represent another Surfaces which can accurately distinguish spatial and temporal changes in temperature are critical for not only flow sensors, microbolometers, process control, but also future applications like electronic skins and soft robotics. Realizing such surfaces requires the deposition of thousands of thermal sensors over large areas, a task ideally suited for printing technologies. Negative temperature coefficient (NTC) ceramics represent the industry standard in temperature sensing due to their high thermal coefficient and excellent stability. A drawback is their complex and high temperature fabrication process and high stiffness, prohibiting their monolithic integration in large area or flexible applications. As a remedy, a printable NTC composite that combines a rapid and scalable all-printed fabrication process with performances that are on par with conventional NTC ceramics is demonstrated. The composite consists of micrometer-sized manganese spinel oxide particles dispersed in a benzocyclobutene matrix. The sensor has a B coefficient of 3500 K, with a 4.0% change in resistance at 25 °C, comparable to bulk ceramics. The selected polymer binder yields a composite exhibiting less than a 1 °C change in resistance to changes in humidity. The sensor's scalability is validated by demonstration of a A4-sized temperature sensing sheet consisting of over 400 sensors.

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mentioning

confidence: 99%

Large‐Area All‐Printed Temperature Sensing Surfaces Using Novel Composite Thermistor Materials

Katerinopoulou

Zalar

Sweelssen

et al. 2018

Adv Elect Materials

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“…[2,4] However, we may not need such accuracy for ambulatory monitoring as a tradeoff to less power consumption. [2,4] However, we may not need such accuracy for ambulatory monitoring as a tradeoff to less power consumption.…”

Section: Wearable Sep Real-time Heart Signal Monitoringmentioning

confidence: 99%

“…[1][2][3][4][5][6][7][8] Wearable ambulatory ECG Vital sign monitoring like electrocardiogram (ECG), is of growing interest for next-generation wearable technologies.…”

Section: Introductionmentioning

confidence: 99%

“…To enable intimate attachment to the body, the package modulus and form factor should approach that of the human skin. [1,3,4,12,13,25,28] In this work, we report on a novel integration of a wearable and stretchable-hybrid SEP with monolithically integrated sensor electrodes and liquid-metal interconnects. [8] Despite significant advancement in wearable electronics, [1, major tradeoffs between form-factor, performance, and functionality remain.…”

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confidence: 99%

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A Stretchable‐Hybrid Low‐Power Monolithic ECG Patch with Microfluidic Liquid‐Metal Interconnects and Stretchable Carbon‐Black Nanocomposite Electrodes for Wearable Heart Monitoring

Luo

Nayak

et al. 2018

Adv Elect Materials

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patches have been recommended by physicians for patients with heart abnormalities to correlate their activities with heart signals. [2] In order for long-duration on-skin monitoring, comfort to the wearer is an important design consideration for these patches. To enable intimate attachment to the body, the package modulus and form factor should approach that of the human skin. Besides enhancing comfort, good electrical contact for high fidelity signal acquisition that is immune to the motion of wearer and environment influences are necessary. [8] Despite significant advancement in wearable electronics, [1, major tradeoffs between form-factor, performance, and functionality remain. For ultrathin skin-like material systems fabricated by ink-printing or microcontact transfer printing, [9][10][11][12][13][14][15][20][21][22][25][26][27] the complexity and signal processing capabilities are typically limited by the weaker transistors or interconnects. Ink-printed components are also limited by lower integration density compared to rigid Silicon CMOS technologies, leading to lower functionality. The increased R-C parasitic with larger and weaker components limits the scalability toward highly-energy-efficiency under low-voltage operations. In contrast, rigid CMOS chips and printed circuit boards (PCBs) require integration with soft components to interface comfortably with the human body. The need for electrical performance with soft and robust mechanical form factor leads us to the codesign of composite materials and electronic circuits/system in a monolithic form of flexible hybrid electronics. [1,3,4,12,13,25,28] In this work, we report on a novel integration of a wearable and stretchable-hybrid SEP with monolithically integrated sensor electrodes and liquid-metal interconnects. The SEP integration involves the combination of a chip-on-board embedded in a moisture-resistant elastomer matrix with microfluidic interconnects, and soft low-resistance electrodes (Figure 1). A stretchable electrocardiogram (ECG) patch (SEP) that monolithically integrates ECG monitoring chip-on-board (COB) with polydimethylsiloxane (PDMS) and liquid-metal interconnects is presented. The 4.8 × 4.8 cm 2 SEPis conformal and robust to mechanical deformation. The use of a siliconon-insulator rigid complementary-metal-oxide-semiconductor chip allows sophisticated power management and signal processing. The chip's dense inputs/output pads are interfaced with coarser liquid-metal interconnects using a dual-sided COB design. A robust ECG signal response (≈100 mV p-p up to 1 kHz), subjected to mechanical deformation and moisture is demonstrated. The SEP allows up to 10% stretch, providing sufficient pliability to enable conformal contact to the human chest. Low profile soft carbon black-PDMS nanocomposite electrodes, robust to deformation, enable good skin contact and allow for low-noise signal acquisition that is comparable to larger commercial wet electrodes.

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“…The demand for flexible electronic devices, such as flexible displays [1], flexible radio frequency identification (RFID) tags [2], wearable electronics and implantable devices [3,4], is rapidly growing. Flexible lithium-ion batteries (LIB) have gained considerable attention as a promising energy storage solution for such applications [5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Flexible and Lightweight Lithium-Ion Batteries Based on Cellulose Nanofibrils and Carbon Fibers

Hagberg

Lindbergh

et al. 2018

Batteries

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Flexible, low-weight electrodes with integrated current collectors based on chopped polyacrylonitrile carbon fibers (CF) were produced using an easy, aqueous fabrication process, where only 4 wt% of TEMPO-oxidized cellulose nanofibrils (CNF) were used as the binder. A flexible full cell was assembled based on a LiFePO 4 (LFP) positive electrode with a CF current collector and a current collector-free CF negative electrode. The cell exhibited a stable specific capacity of 121 mAh g −1 based on the LFP weight. The CF in the negative electrode acted simultaneously as active material and current collector, which has a significant positive impact on energy density. Stable specific capacities of the CF/CNF negative electrode of 267 mAh g −1 at 0.1 C and 150 mAh g −1 at 1 C are demonstrated. The LFP/CNF with CF/CNF, as the current collector positive electrode (LFP-CF), exhibited a good rate performance with a capacity of~150 mAh g −1 at 0.1 C and 133 mAh g −1 at 1 C. The polarization of the LFP-CF electrode was similar to that of a commercial Quallion LFP electrode, while much lower compared to a flexible LFP/CNF electrode with Al foil as the current collector. This is ascribed to good contact between the CF and the active material.

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Flexible Hybrid Electronics: Direct Interfacing of Soft and Hard Electronics for Wearable Health Monitoring

Cited by 263 publications

References 27 publications

Large‐Area All‐Printed Temperature Sensing Surfaces Using Novel Composite Thermistor Materials

Large‐Area All‐Printed Temperature Sensing Surfaces Using Novel Composite Thermistor Materials

A Stretchable‐Hybrid Low‐Power Monolithic ECG Patch with Microfluidic Liquid‐Metal Interconnects and Stretchable Carbon‐Black Nanocomposite Electrodes for Wearable Heart Monitoring

Flexible and Lightweight Lithium-Ion Batteries Based on Cellulose Nanofibrils and Carbon Fibers

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