Network topologies dictate electromechanical coupling in liquid metal–elastomer composites

Soft Matter ◽  
2020 ◽  
Vol 16 (38) ◽  
pp. 8818-8825
Author(s):  
Navid Zolfaghari ◽  
Pratik Khandagale ◽  
Michael J. Ford ◽  
Kaushik Dayal ◽  
Carmel Majidi
Keyword(s):  
Liquid Metal ◽  
Computational Modeling ◽  
Electrical Resistance ◽  
Electromechanical Coupling ◽  
Large Strains ◽  
Network Topologies ◽  
Elastomer Composites ◽  
Metal Droplets

Conductive traces of elastomer embedded with liquid metal droplets exhibit little change in electrical resistance when stretched to large strains. Computational modeling is performed to better understand this remarkable piezoresistive property.

Studying changes in the electrical resistance of carbon-nanotubes-modified elastomers during their compression, stretching and torsion

2019 ◽  
pp. 128-138
Author(s):  
V. S. Yagubov ◽  
A. V. Shchegolkov ◽  
A. V. Shchegolkov ◽  
N. R. Memetov
Keyword(s):  
Composite Material ◽  
Smart Materials ◽  
Electrical Resistance ◽  
Materials Science ◽  
Measuring System ◽  
Constant Current ◽  
Matrix Composition ◽  
Space Industry ◽  
Different Types ◽  
Elastomer Composites

Developing "smart" materials with improved both structural and functional characteristics is one of the promising areas of materials science. Measuring the electrical resistance of CNTs-modified (various mass contents) polymers and in particular, elastomers during performing several tests (compression, stretching, and torsion) at a constant current is relevant in electrical engineering, mechanical engineering, aviation, and space industry. Changes in the elastomer shape under different types of testing lead to the destruction of macromolecules and the structuring of the material as a whole. Therefore, it is important to study the effect of CNTsbased modifying fillers on the elastomer. When compressing, stretching or twisting the nano-modified elastomer, along with the mutual movement of its macromolecular fragments and aggregates, the modifier particles also move, which generally determines the transport of electrons in the resulting structure and affects the physical and mechanical parameters of the composite material. To conduct studies, elastomers containing different amounts of a CNTs-based modifying filler were prepared. To investigate and elucidate relevant dependencies, a measuring system (MS) was constructed, which makes it possible to determine electrical resistance values of the composite material with different CNTs contents in the polymer matrix composition exposed to various mechanical loads. Basing the research results, it was established that the electrical resistance of the elastomer composites modified with 1.0–2.5 wt.% CNTs decreases when compressing from 0 to 100 N, whereas when the compression force ranges from 100 to 350 N, the electrical resistance remains unchanged. When the elastomer composites modified with 2–2.5 wt.% CNTs were stretched by 30–40 %, the electrical resistance was found to increase from 5·103 to 1.9·107 Ω.

scholarly journals In-situ monitoring for liquid metal jetting using a millimeter-wave impedance diagnostic

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Tammy Chang ◽  
Saptarshi Mukherjee ◽  
Nicholas N. Watkins ◽  
David M. Stobbe ◽  
Owen Mays ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Millimeter Wave ◽  
Manufacturing Systems ◽  
Wave Impedance ◽  
In Situ Monitoring ◽  
Full Wave ◽  
Drop On Demand ◽  
The Time Domain ◽  
Metal Droplets

AbstractThis article presents a millimeter-wave diagnostic for the in-situ monitoring of liquid metal jetting additive manufacturing systems. The diagnostic leverages a T-junction waveguide device to monitor impedance changes due to jetted metal droplets in real time. An analytical formulation for the time-domain T-junction operation is presented and supported with a quasi-static full-wave electromagnetic simulation model. The approach is evaluated experimentally with metallic spheres of known diameters ranging from 0.79 to 3.18 mm. It is then demonstrated in a custom drop-on-demand liquid metal jetting system where effective droplet diameters ranging from 0.8 to 1.6 mm are detected. Experimental results demonstrate that this approach can provide information about droplet size, timing, and motion by monitoring a single parameter, the reflection coefficient amplitude at the input port. These results show the promise of the impedance diagnostic as a reliable in-situ characterization method for metal droplets in an advanced manufacturing system.

Soft and Stretchable Thermoelectric Generators Enabled by Liquid Metal Elastomer Composites

2020 ◽  
Vol 12 (15) ◽  
pp. 17921-17928 ◽  
Author(s):  
Mason Zadan ◽  
Mohammad H. Malakooti ◽  
Carmel Majidi
Keyword(s):  
Liquid Metal ◽  
Thermoelectric Generators ◽  
Elastomer Composites

scholarly journals Shaping and Controlled Fragmentation of Liquid Metal Droplets through Cavitation

2018 ◽  
Vol 8 (1) ◽  
Author(s):  
M. S. Krivokorytov ◽  
Q. Zeng ◽  
B. V. Lakatosh ◽  
A. Yu. Vinokhodov ◽  
Yu. V. Sidelnikov ◽  
...  
Keyword(s):  
Liquid Metal ◽  
Metal Droplets
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