Category Archives: 미분류

An autonomously electrically self-healing liquid metal–elastomer composite for robust soft-matter robotics and electronics

Author: Eric J. Markvicka, and Carmel Majidi

Journal: Nature materials

Publication date: 21 May 2018

Summarized by Hyuk Park

 

– Material architecture and framework
v. Creating circuit interconnects that are capable of autonomous, electrical self-healing
v. Liquid metal(LM) alloy – EGaIn + silicone elastomer
v. Insulating property even high LM fraction (> 50%)
v. Extreme local pressure(damaged) → locally conductive pathways (conductivity of 1.37 x 10^3 Sm^-1)

– 2-phenyl7-alkylated-[1]benzothieno[3,2-b][1]benzothiophene (Ph-BTBT-Cn; n≥ 5)
v. High layered crystallinity
v. Bilayer type layered herringbone structure
v. Strong intermolecular interaction
v. Flake-like crystals composed of multiply-stacked molecular bilayer (no single layer)

1.png

Fig. 1

– Geometrical frustration – different alkyl chain lengths
v. Blade coating
v. Ph-BTBT-Cn and Ph-BTBT-Cn` (n` > n)
v. φlong: volume fraction of longer chain molecules
v. Longer alkyl chain is more effective for fabricating SMBs than that of shorter ones

2.png

Fig. 2

3.png

Fig. 3

v. single component film → flat outer surface → multilayer crystallization

4.png

Fig. 4

 

– SMB measurement
v. AFM – SMB thickness = 4.4 nm
v. High resolution AFM alkyl chain difference = 170 pm
v. In-plane XRD: no out-of-plane diffraction → single layer
v. X-ray reflectivity: calculation = experiment

5.png

Fig. 5

 

– Semiconducting properties – bottom gate TFTs
v. Saturation mobility of 2.6 cm2/Vs
v. Hysteresis due to scattering of carriers with the formation of traps at semiconductor/air interface

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Fig. 6

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Low-Power, Electrochemically Tunable Graphene Synapses for Neuromorphic Computing

Journal: Advanced Materials

Authors: M. T. Sharbati and F. Xiong et al.

Affiliation: The University of Pittsburgh (USA)

Publication date: 2018.07.23

Summarized by Inyeol Yun

 

– Background
v. The neural network in a human brain has ≈1011 neurons. Each neuron is typically   connected to ≈5,000 to 10,000 other neurons through synapse.
v. Synapse plasticity is the ability of synapses to strengthen or weaken over time, in   response to increases or decreases in their activity (Wikipedia). It related to memory   function.
v. Typical artificial synapses cannot mimic the analog behaviors of biological synapses.
v. In this paper, authors demonstrate the synapse plasticity using “nano-battery”   technology. (Fig. 1)

1.png

<Fig. 1>

– Structure & Fabrication
v. Graphene layers – Solid electrolyte (LiClO4 in poly(ethylene oxide) (PEO) – Lithium   iron phosphate (LFP) (Fig. 2)

2.png

<Fig. 2>

 v. Metal contacts (80 nm of Cu) were defined by e-beam lithography and deposited   through e-beam evaporation.
v. Real image (Fig. 3)

3.png

<Fig. 3>

– Results
v. Raman spectroscopy shows weakening of bond between graphene layers as   increasing Li-ion. (Fig. 4)

4.png

<Fig. 4>

 v. Resistance change (Figure. 5)

5.png

<Fig. 5>

Hydraulically amplified self-healing electrostatic actuators with muscle-like performance

Journal: MATERIALS SCIENCE

Author: Xin Lin , Berthold Wegner et. al

Affiliation: Department of Mechanical Engineering, University of Colorado

Publication date: 2018.01.05

Summarized by Taewon Seo

 

– HASEL actuators
v. Schematic of a donut HASEL actuator (Fig. 1)
v. Schematic of a stack of five donut HASEL actuators (Fig. 2)
v. Schematic of a single-unit planar HASEL actuator (Fig. 3)

fig1

Fig. 1

fig22.jpg

Fig. 2

fig3.jpg

Fig. 3

 

– Fabrication
v. For a donut HASEL (Fig. 4)
v. For a single-unit planar HASEL (Fig. 5)
v. Flexible electrodes of PAM-LiCl hydrogels (thickness of 200μm)
v. Self-healing Liquid dielectric of Envirotemp FR3 (Cargill)

 

fig4.jpg

Fig. 4

fig5.jpg

Fig. 5

 

– Self healing
v. Self-healing from dielectric breakdown (Fig. 6)
v. Self-healing capabilities (Fig. 7)
v. Supporting information : http://science.sciencemag.org/highwire/filestream/704298/field_highwire_adjunct_files/2/aao6139s2.mp4

fig6.jpg

Fig. 6

fig7.jpg

Fig. 7

 

– Result
v. Actuation strain of a donut HASEL (Fig. 8)
v. Cycle life of a donut HASEL (Fig. 9)
v. Actuation strain of a single-unit planar HASEL (Fig. 10)
v. Supporting information : https://www.youtube.com/watch?v=M4qcvTeN8k0

fig8.jpg

Fig. 8

fig9

Fig. 9

fig10.jpg

Fig. 10

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

fig2

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)

fig6

Fig. 6

fig7

Fig. 7