Stretchability and compressibility of a novel layout design for flexible electronics based on bended wrinkle geometries

Yan, Zhengang; Wang, B.L.; Wang, K.F.

doi:10.1016/j.compositesb.2018.11.123

Cited by 22 publications

(15 citation statements)

References 39 publications

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“…For example, Raghav et al had studied the wedging of a graphene bilayer by water molecules 14 . The first on-purpose fabrication of the wrinkles was demonstrated in 2011 15 , followed by multiple studies on modeling the wrinkle theoretically/numerically 11 , 16 , 17 .…”

Section: Introductionmentioning

confidence: 99%

Computational study of the water-driven graphene wrinkle life-cycle towards applications in flexible electronics

Kashyap

Yang

Datta

2020

Sci Rep

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The ubiquitous presence of wrinkles in two-dimensional materials alters their properties significantly. It is observed that during the growth process of graphene, water molecules, sourced from ambient humidity or transferred method used, can get diffused in between graphene and the substrate. The water diffusion causes/assists wrinkle formation in graphene, which influences its properties. The diffused water eventually dries, altering the geometrical parameters and properties of wrinkled graphene nanoribbons. Our study reveals that the initially distributed wrinkles tend to coalesce to form a localized wrinkle whose configuration depends on the initial wrinkle geometry and the quantity of the diffused water. The movement of the localized wrinkle is categorized into three modes—bending, buckling, and sliding. The sliding mode is characterized in terms of velocity as a function of diffused water quantity. Direct bandgap increases linearly with the initial angle except the highest angle considered (21°), which can be attributed to the electron tunneling effect observed in the orbital analysis. The system becomes stable with an increase in the initial angle of wrinkle as observed from the potential energy plots extracted from MD trajectories and confirmed with the DOS plot. The maximum stress generated is less than the plastic limit of the graphene.

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Section: Introductionmentioning

confidence: 99%

Computational study of the water-driven graphene wrinkle life-cycle towards applications in flexible electronics

Kashyap

Yang

Datta

2020

Sci Rep

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“…To further meet the demand for large stretchability in practical applications, specialized structural layouts and mechanical designs are required. The “wavy” designs shown in Figure b provide a representative example, in which the applied tensile strains of the overall system are accommodated mainly through changes in the amplitudes and wavelengths of the wavy structures …”

Section: Structural Designs Of Devices and Systemsmentioning

confidence: 99%

“…For the full bonding strategy, many mechanics models have been developed to predict the configurations of the wavy ribbon structures, as well as their stretchabilities . In the regime of small deformations ( ɛ pre ≤ 5%), an energetic approach based on the small‐deformation theory was developed to determine the buckled shapes, in which the out‐of‐plane displacement of the ribbon is assumed as a sinusoidal profile.…”

Section: Structural Designs Of Devices and Systemsmentioning

confidence: 99%

Mechanically‐Guided Structural Designs in Stretchable Inorganic Electronics

et al. 2019

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but remove the constraints of rigid, brittle, planar, wafer substrates, through the strategic integration with soft elastomers. [1][2][3][4][5][6][7][8][9][10][11][12][13][14] Compared with the conventional rigid devices, stretchable inorganic electronics not only allow large deformations without degradation in electronic performances, but also yield conformal integration with the complex surfaces of tissues of the human body. [8,[15][16][17][18][19][20] Due to these unique advantages, stretchable inorganic electronics technologies significantly broaden the application areas of conventional electronics, and also enable novel uses in health monitoring, advanced humanmachine interfaces and internet of things, such as epidermal electronics, [21][22][23][24][25] curvilinear electronics, [26][27][28] deformable optoelectronics, [29][30][31][32][33][34] transient electronics, [35][36][37] and many other bioelectronic systems. [38][39][40] With a series of rapid developments over more than a dozen of years, stretchable inorganic electronic systems now define a well-recognized and active field of study, encompassing a diverse range of fundamental and applied topics, [41][42][43][44][45][46][47][48][49][50][51][52][53] including, for example, a collection of unusual material/structure designs and techniques to integrate hard inorganic semiconductor components and geometrically structural interconnects in optimized layouts onto patterned soft substrates. [7,54,55] Stretchable electronics have achieved high levels of sophistication largely through the use of inorganic active materials. According to the utility of different conductive materials, stretchable inorganic electronics can be classified into three categories, including those based on the composite stretchable conductors, liquid metals, and structured semiconductors/metals. [49,[56][57][58] In the first category, novel nanomaterials dispersed into a polymer matrices form composite films or fibers, by coating, dipping, printing, and electrospinning. Various nanomaterials have been exploited in this context, including metal nanoparticles, nanowires, nanoflakes, and the allotropes of carbon (carbon nanotubes, graphene, and carbon blacks). [59][60][61][62][63][64][65][66] A key to this strategy is in maintaining interconnected pathways through these nanomaterials to enable highly conductive channels when the substrate is stretched. [67][68][69][70][71] Despite great progress, the conductivities of such composites are typically lower than those of conventional metals. The second category of stretchable inorganic conductors relies on liquid metals patterned and encapsulated into channels of elastomeric materials. [72,73] Such constructs can be bent and stretched to levels beyond those possible with conventional electronic materials.Over the past decade, the area of stretchable inorganic electronics has evolved very rapidly, in part because the results have opened up a series of unprecedented applications with broad interest and potential for impact, especially in bio-inte...

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“…2, or the global buckling critical strain in Eq. 7, controls the deformation mode 48,49 . By setting the condition (e cr ) b = e cr , the critical width w cr , which separates the global buckling and local surface wrinkles, is obtained as…”

Section: Theory Overviewmentioning

confidence: 99%

“…It was perceived that global buckling will occur if w > w cr , and local wrinkling will occur if w < w cr . Although the configuration of local wrinkles developed on a globally bent structure has recently been proposed [48][49][50] , theoretical considerations in the literature have generally ignored the possibility that wrinkling and buckling can codevelop, starting from a fully flat geometry. It will be shown in the following sections that a transitional state (with both wrinkles and global buckle) can be captured, by employing the current direct numerical simulation approach.…”

Section: Theory Overviewmentioning

confidence: 99%

Instabilities of Thin Films on a Compliant Substrate: Direct Numerical Simulations from Surface Wrinkling to Global Buckling

Nikravesh

Ryu

Shen

2020

Sci Rep

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For structures consisting of a thin film bonded to a compliant substrate, wrinkling of the thin film is commonly observed as a result of mechanical instability. Although this surface undulation may be an undesirable feature, the development of new functional devices has begun to take advantage of wrinkled surfaces. The wrinkled structure also serves to improve mechanical resilience of flexible devices by suppressing crack formation upon stretching and bending. If the substrate has a reduced thickness, buckling of the entire structure may also occur. It is important to develop numerical design tools for predicting both wrinkle and buckle formations. In this paper we report a comprehensive finite element-based study utilizing embedded imperfections to directly simulate instabilities. The technique overcomes current computational challenges. The temporal evolution of the wrinkling features including wavelength and amplitude, as well as the critical strains to trigger the surface undulation and overall structural buckling, can all be predicted in a straightforward manner. The effects of model dimensions, substrate thickness, boundary condition, and composite film layers are systematically analyzed. In addition to the separate wrinkling and buckling instabilities developed under their respective geometric conditions, we illustrate that concurrent wrinkling and buckling can actually occur and be directly simulated. The correlation between specimen geometry and instability modes, as well as how the deformation increment size can influence the simulation result, are also discussed.

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Stretchability and compressibility of a novel layout design for flexible electronics based on bended wrinkle geometries

Cited by 22 publications

References 39 publications

Computational study of the water-driven graphene wrinkle life-cycle towards applications in flexible electronics

Computational study of the water-driven graphene wrinkle life-cycle towards applications in flexible electronics

Mechanically‐Guided Structural Designs in Stretchable Inorganic Electronics

Instabilities of Thin Films on a Compliant Substrate: Direct Numerical Simulations from Surface Wrinkling to Global Buckling

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