Electrical and thermal effects on electromechanical performance of stretchable thin gold films on PDMS substrates for stretchable electronics

Abstract

Stretchable electrodes comprising thin gold films with initial nanocracks on elastic substrates of poly(dimethylsiloxane) are developed in this work, which can be stretched reversibly while maintaining conductivity to an applied uniaxial strain as large as 120%. Reliable electromechanical performance is essential for the application of stretchable electronics as bioelectronic interfaces under various working conditions; therefore, the electrical and thermal effects on the electromechanical performance of the stretchable gold film electrodes are investigated in this work. It is found that the stretchability deteriorates to some extent depending on the electrical and thermal treatments. Microstructures and stress analysis in the cracks are studied, along with crack quantification. It is believed that the decrease of the stretchability is ascribed to the combination of the crack widening by thermal mismatch stress and crack tip smoothening by the electromigration phenomenon. Therefore, the current density and temperature through the electrodes should be controlled within a certain range for wide applications in order to maintain a stable performance of the electrodes. This study also provides some guiding significance for the design of other stretchable electronic devices composed of two materials with large different physical properties.

A soft and stretchable bilayer electrode array with independent functional layers for the next generation of brain machine interfaces

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Self-Closing Stretchable Cuff Electrodes for Peripheral Nerve Stimulation and Electromyographic Signal Recording

“…The concept and the detailed fabrication processes of the self-closing stretchable cuff electrode are demonstrated schematically in Figure . In the previous study, − we developed SNCG films, which have been applied for fabricating stretchable electrodes. The resulting electrodes could maintain high conductivity even under the largest uniaxial strain of 110%.…”

Electrical Failure Mechanism in Stretchable Thin-Film Conductors

“…The initial electrode is flat and has intrinsic nanocracks randomly distributed across the electrode (Figure c). The nanocracks were quantitatively analyzed in our previous work in detail . As the electrical current through the electrode is increased, the electrode starts to bend due to a large thermal mismatch.…”

“…The nanocracks were quantitatively analyzed in our previous work in detail. 41 As the electrical current through the electrode is increased, the electrode starts to bend due to a large thermal mismatch. Once the current approaches the critical value, the voltage between the tips of the cracks becomes so high, leading to temperatures as high as 500 K. At the moment, the cracks propagate and coalesce rapidly and form a large fracture.…”