Monthly Archives: September 2017

Self-assembled three dimensional network designs for soft electronics

Journal: Nature communications

Author: Kyung-In Jang and John A. Rogers et al.

Affiliation: Daegu Gyeongbuk Institute of Science and Technology, Northwestern University

Publication date: 2017.06.21

Summarized by Jinpyeo Jeung

 

– 3D helical coil (Fig.1)
v. 2D structures limit performance for systems that require low modulus, elastic mechanics in compact designs.
v. 2D precursors spontaneously transform into desired 3D shapes.
v. Compressive forces induced by releasing the prestrain cause the 2D precursor to geometrically transform.
v. Two ends include small discs that form strong covalent siloxane bonds to and substrate.

fig1.png

Fig. 1

 

– Result
v. Enables high levels of strechability and mechanical robustness, without the propensity for localized crack formation or fracture.
v. The elastic stretchability of the 3D helices significantly exceeds that of the 2D serpentines. (Fig.2)
v. Deformations of the 2D serpentine lead to sharp, unavoidable stress concentrations at the arc regions but 3D helices shows uniform stress. (Fig.3)

fig2.png

Fig. 2

fig3.png

Fig. 3

 

– Application
v. Actual appearance. (Fig. 4, Fig. 5)
v. It can be applied to various wireless, skin-compatible electronics. (Fig. 6)

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Fig. 4

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Fig. 5

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Fig. 6

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Accelerated Wound Healing on Skin by Electrical Stimulation with a Bioelectric Plaster

Journal: Advanced Healthcare Materials

Author: Hiroyuki Kai and Matsuhiko Nishizawa et al.

Affiliation: Tohoku University, Japan

Publication date: 2017.09.20

Summarized by Inyeol Yun

 

– Bioelectric Plaster (Fig. 1)
v. Wound healing on skin involves cell migration and proliferation in response to endogenous electric current.
v. External electrical stimulation is used to promote these biological processes for the treatment of chronic wounds.
v. An enzymatic biofuel cell (EBFC) that generates ionic current along the surface of the skin by enzymatic electrochemical reactions for more than 12h. (Fig. 2)

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Fig. 1

fig2.png

Fig. 2

 

– Materials
v. Cathode : carbon fiber fabric coated with carbon nanotubes, on which reducing enzyme bilirubin oxidase
v. Anode : carbon fiber fabric coated with carbon nanotubes, on which oxidizing enzyme fructose dehydrogenase
v. Hydrogel : citrate buffer solutions with different concentrations of fructose.
v. Stretchable resistor : PEDOT/PU film

 

– Result
v. Time-dependent current changes of the bioelectric plaster with different external resistances and citrate buffer solutions with different concentrations. (Fig. 3)
v. Changes of wound width and height of Group A (gray), Group B (red), and Group C (blue) (Fig. 4)
v. Microscopy images of skin sections at the wound at day 7: a) the boundary between normal tissue and healed tissue, b) the area of normal tissue, c) the area of healed tissue, d) dermis, e) fat tissue (Fig. 5)  Group C > Group A on scar after healing, wound closure speed.

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Fig. 3

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Fig. 4

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Fig. 5

 

– Reference
v. https://en.wikipedia.org/wiki/Enzymatic_biofuel_cell (accessed September 26, 2017)

Self-Powered, Paper-Based Electrochemical Devices for Sensitive Point-of-Care Testing

Journal: Advanced Materials Technologies

Publication date: 2017.08.22

Summarized by Inyeol Yun

 

– Self-powered, paper-based electrochemical devices (SPEDs)
v. Structure (Fig. 1)
v. Electrochemical detection (Fig. 2), colorimetric test
v. Triboelectric generator (TEG) (Fig. 3)

fig1

Fig. 1

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Fig. 2

fig3

Fig. 3

 

– Fabrication
v. Biomarker part (Fig. 4)
v. TEG part (Fig. 5)

fig4

Fig. 4

fig5

Fig. 5

 

– Result
v. Electrochemical detection (Fig. 6)
v. TEG (Fig. 7)

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Fig. 6

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Fig. 7

Highly Flexible and Efficient Fabric Based Organic Light-Emitting Devices for Clothing-Shaped Wearable Displays

Journal: Scientific Reports

Publication date: 2017.07.25

Summarized by Seongmin Park

 

– Methods to achieve actual clothing-shaped information displays

  1. Attaching a display panel onto a piece of clothing → Flexibility decreases
  2. Fabricating of light emitting fiber → Low emission performance
  3. Fabricating an information display onto a fabric → Best choice

– Novel Concept

v. Spin coating of the silane-based film on fabric (Fig. 1, 2)

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Fig. 1

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Fig. 2

– Structure

  1. Base Structure (Fig.3)

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Fig. 3

     2. Endurance vs. Number of dyads (Fig. 4, 5)

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Fig. 4

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Fig. 5

     3. Optimized Structure (Fig. 6)

fig6

Fig. 6

     4. Good Endurance

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Fig. 7

 

– Results

  1. Similar performance (Fig. 8)

fig8

Fig. 8

     2. Light emitting performances vs. bending radius (Fig. 9)

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Fig. 9

     3. Comparison between OLEDs on fabric and OLEDs on PET (Fig. 10)

fig10

Fig. 10

     4. Cyclic bending with bending radius of 1 cm (Fig. 11)

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Fig. 11