Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes

Matsuhisa, Naoji; Inoue, Daishi; Zalar, Polona; Jin, Hanbit; Matsuba, Yorishige; Itoh, Akira; Yokota, Tomoyuki; Hashizume, Daisuke; Someya, Takao

doi:10.1038/nmat4904

Cited by 602 publications

(601 citation statements)

References 49 publications

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“…Especially, for the interconnect and the electrodes, they constitute major portions of the patch and thus necessary for them to be soft and stretchable. [15,17,24] Composite materials tend to be less conductive than solid metals since they are typically conductive polymers or granular conducting particles/structures in a dielectric matrix. [3,[9][10][11][12][13][14]25] Typically with thin meandering metal wires, the approach provides the best conductivity.…”

Section: Soft Component Integrationmentioning

confidence: 99%

“…[2] In order for long-duration on-skin monitoring, comfort to the wearer is an important design consideration for these patches. 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. Besides enhancing comfort, good electrical contact for high fidelity signal acquisition that is immune to the motion of wearer and environment influences are necessary.…”

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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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Section: Soft Component Integrationmentioning

confidence: 99%

mentioning

confidence: 99%

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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“…[13,14] Distribution of nanomaterial fillers has a crucial influence on the mechanical and electrical properties of the sensors. [15][16][17] More discussions on the influence of the filler distribution and novel dispersion techniques to achieve uniform distribution can be found in previous published review papers. [18][19][20] In addition to the intrinsic good stretchability of nanomaterials, structural engineering is commonly used to enhance the stretchability.…”

Section: Introductionmentioning

confidence: 99%

Nanomaterial‐Enabled Wearable Sensors for Healthcare

Yao

Swetha

Zhu

2017

Adv Healthcare Materials

432

280

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humidity level, and concentration of harmful gases, and airborne particulates can provide valuable information for the prediction, management, and treatment of chronic diseases. [4,5] In addition to the applications in wearable health monitoring, continuous tracking of daily and sports activities can offer an efficient way to assess the well-being and athletic performances. [6] In order to ensure a robust and conformal contact with the curvilinear, coarse, and dynamic surface of skin without impeding daily activities, the wearable sensor should have low modulus and high stretchability. The epidermis has a modulus of 140-600 kPa while the dermis has an even lower modulus of 2-80 kPa. [7] Skin itself can be stretched elastically up to 15% and with the help of wrinkles and creases, the overall stretchability can reach as high as 100% during daily motions. [8] In addition to good wearability, wearable sensors should be highly sensitive, lightweight, low-cost, and with low power consumption. To achieve these features, nanomaterials that are compliant, possessing larger surface area and exceptional material properties, and compatible with low-cost fabrication processes are widely employed as building blocks for developing wearable sensors.In this review, we start from a brief overview of nanomaterials, their related structural designs and fabrication processes (Section 2). Following that, recent advances of nanomaterialenabled wearable sensors including temperature, electrophysiological, strain, tactile, electrochemical, and other sensors will be summarized (Section 3). A survey on the integration of multiple sensors and other components into wearable systems will be given in Section 4. The application of nanomaterialenabled wearable sensors for healthcare including health monitoring, activity tracking, and electronic skin will be presented in Section 5. The challenges and opportunities will be discussed at the end. Nanomaterials, Structural Designs, and Fabrication ProcessesNanomaterials can be classified into two categories-top-down fabricated ones and bottom-up synthesized ones. [9] The focus of this review is on the wearable sensors based on bottom-up synthesized nanomaterials. Nanomaterials can be synthesized into various dimensions, from 0D such as metallic nanoparticles (NPs), to 1D such as carbon nanotubes (CNTs), and metallic nanowires (NWs), to 2D such as graphene and transition metal Highly sensitive wearable sensors that can be conformably attached to human skin or integrated with textiles to monitor the physiological parameters of human body or the surrounding environment have garnered tremendous interest. Owing to the large surface area and outstanding material properties, nanomaterials are promising building blocks for wearable sensors. Recent advances in the nanomaterial-enabled wearable sensors including temperature, electrophysiological, strain, tactile, electrochemical, and environmental sensors are presented in this review. Integration of multiple sensors for multimodal sensing and integration with...

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“…17,18 Recent efforts toward developing intrinsically stretchable conductors using conductive polymers and macromolecular additives have led to conductive polymers blends that remain conductive under strain values exceeding 100%. 2,3,11,19 The applicability of conductive polymer blends is limited due to low electrical conductivity values, leading to the continued investigation of composite elastic conductors. 2,20–22 The most common approaches are liquid metal-filled channels within soft elastomer matrixes 8,23,24 or conductive networks composed of nanowires 25,26 or nanotubes 27,28 backfilled with an elastomeric component.…”

Section: Introductionmentioning

confidence: 99%

Spray-Processed Composites with High Conductivity and Elasticity

Vural

Behrens

Hwang

et al. 2018

ACS Appl. Mater. Interfaces

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Highly conductive elastic composites were constructed using multistep solution-based fabrication methods that included the deposition of a nonwoven polymer fiber mat through solution blow spinning and nanoparticle nucleation. High nanoparticle loading was achieved by introducing silver nanoparticles into the fiber spinning solution. The presence of the silver nanoparticles facilitates improved uptake of silver nanoparticle precursor in subsequent processing steps. The precursor is used to generate a second nanoparticle population, leading to high loading and conductivity. Establishing high nanoparticle loading in a microfibrous block copolymer network generated deformable composites that can sustain electrical conductivities reaching 9000 S/cm under 100% tensile strain. These conductive elastic fabrics can retain at least 70% of their initial electrical conductivity after being stretched to 100% strain and released for 500 cycles. This composite material system has the potential to be implemented in wearable electronics and robotic systems.

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Printable elastic conductors by in situ formation of silver nanoparticles from silver flakes

Cited by 602 publications

References 49 publications

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

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

Nanomaterial‐Enabled Wearable Sensors for Healthcare

Spray-Processed Composites with High Conductivity and Elasticity

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