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Wrinkle motifs in thin films.

Budrikis Z, Sellerio AL, Bertalan Z, Zapperi S - Sci Rep (2015)

Bottom Line: Although these patterns are part of everyday experience and are important in industry, they are not completely understood.Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates.Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales.

View Article: PubMed Central - PubMed

Affiliation: ISI Foundation, Via Alassio 11/c, 10126 Torino, Italy.

ABSTRACT
On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as 'telephone cord' buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales.

No MeSH data available.


Related in: MedlinePlus

Avoiding wrinkles and substrate patterning-driven delamination occur in both micro- and macroscopic systems, and are reproduced by a coarsegrained model.Simulated 1 × 1 μm2 (a) monolayer and (b) 5-layer graphene sheet on a substrate decorated with spherical particles of diameter 8 nm, placed in positions determined by digitization of the experimental micrograph shown in panel (c). Red dots indicate the particle centres. (c) Atomic force micrograph from Ref. 17 (doi: 10.1103/PhysRevX.2.041018), showing a 1 × 1 μm2 region of graphene exfoliated onto a substrate decorated with nanoparticles of mean diameter 7.4 nm. (d,e) Close-ups of an example avoiding pair of wrinkles found in experiment and simulation, as highlighted by the blue boxes in panels (a) and (c). (f,g) Close-ups of a region in which the monolayer sheet conforms to the substrate but the 5-layer sheet delaminates, as indicated by the green ellipses in panels (a) and (b). (h) Quantitative agreement between simulation and experiment is evidenced by histograms of the number of wrinkles emanating from each particle, as counted from the images in panels (a) and (b). Error bars correspond to the square root of each count. (i,j) Avoiding wrinkle-like features in geomembranes. The human figure in panel (i) illustrates the scale; panel (j) shows a close-up of the highlighted region, which contains an avoiding pair. Image courtesy Wisconsin Department of Natural Resources38.
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f1: Avoiding wrinkles and substrate patterning-driven delamination occur in both micro- and macroscopic systems, and are reproduced by a coarsegrained model.Simulated 1 × 1 μm2 (a) monolayer and (b) 5-layer graphene sheet on a substrate decorated with spherical particles of diameter 8 nm, placed in positions determined by digitization of the experimental micrograph shown in panel (c). Red dots indicate the particle centres. (c) Atomic force micrograph from Ref. 17 (doi: 10.1103/PhysRevX.2.041018), showing a 1 × 1 μm2 region of graphene exfoliated onto a substrate decorated with nanoparticles of mean diameter 7.4 nm. (d,e) Close-ups of an example avoiding pair of wrinkles found in experiment and simulation, as highlighted by the blue boxes in panels (a) and (c). (f,g) Close-ups of a region in which the monolayer sheet conforms to the substrate but the 5-layer sheet delaminates, as indicated by the green ellipses in panels (a) and (b). (h) Quantitative agreement between simulation and experiment is evidenced by histograms of the number of wrinkles emanating from each particle, as counted from the images in panels (a) and (b). Error bars correspond to the square root of each count. (i,j) Avoiding wrinkle-like features in geomembranes. The human figure in panel (i) illustrates the scale; panel (j) shows a close-up of the highlighted region, which contains an avoiding pair. Image courtesy Wisconsin Department of Natural Resources38.

Mentions: In those experiments, graphene wrinkles are seen to form pairs that approach each other but do not coalesce17 (see Fig. 1), as also confirmed by atomistic simulations18. Such avoiding wrinkle pairs are not just a curiosity of graphene sheets on patterned substrates, and are found not only in other thin films and possibly even in macroscopic sheets such as geomembranes used to line landfills, an example of which is shown in Fig. 1. Other examples from the physics and engineering literature are listed in Table 1. Furthermore, similar avoiding patterns are widely observed in “en passant” cracks2021, which have a universal shape, independent of material properties21. Despite their ubiquity, the physics of avoiding wrinkle pairs is largely unexplored and a quantitative understanding is lacking of when avoiding pairs form and the morphology they take.


Wrinkle motifs in thin films.

Budrikis Z, Sellerio AL, Bertalan Z, Zapperi S - Sci Rep (2015)

Avoiding wrinkles and substrate patterning-driven delamination occur in both micro- and macroscopic systems, and are reproduced by a coarsegrained model.Simulated 1 × 1 μm2 (a) monolayer and (b) 5-layer graphene sheet on a substrate decorated with spherical particles of diameter 8 nm, placed in positions determined by digitization of the experimental micrograph shown in panel (c). Red dots indicate the particle centres. (c) Atomic force micrograph from Ref. 17 (doi: 10.1103/PhysRevX.2.041018), showing a 1 × 1 μm2 region of graphene exfoliated onto a substrate decorated with nanoparticles of mean diameter 7.4 nm. (d,e) Close-ups of an example avoiding pair of wrinkles found in experiment and simulation, as highlighted by the blue boxes in panels (a) and (c). (f,g) Close-ups of a region in which the monolayer sheet conforms to the substrate but the 5-layer sheet delaminates, as indicated by the green ellipses in panels (a) and (b). (h) Quantitative agreement between simulation and experiment is evidenced by histograms of the number of wrinkles emanating from each particle, as counted from the images in panels (a) and (b). Error bars correspond to the square root of each count. (i,j) Avoiding wrinkle-like features in geomembranes. The human figure in panel (i) illustrates the scale; panel (j) shows a close-up of the highlighted region, which contains an avoiding pair. Image courtesy Wisconsin Department of Natural Resources38.
© Copyright Policy - open-access
Related In: Results  -  Collection

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getmorefigures.php?uid=PMC4355740&req=5

f1: Avoiding wrinkles and substrate patterning-driven delamination occur in both micro- and macroscopic systems, and are reproduced by a coarsegrained model.Simulated 1 × 1 μm2 (a) monolayer and (b) 5-layer graphene sheet on a substrate decorated with spherical particles of diameter 8 nm, placed in positions determined by digitization of the experimental micrograph shown in panel (c). Red dots indicate the particle centres. (c) Atomic force micrograph from Ref. 17 (doi: 10.1103/PhysRevX.2.041018), showing a 1 × 1 μm2 region of graphene exfoliated onto a substrate decorated with nanoparticles of mean diameter 7.4 nm. (d,e) Close-ups of an example avoiding pair of wrinkles found in experiment and simulation, as highlighted by the blue boxes in panels (a) and (c). (f,g) Close-ups of a region in which the monolayer sheet conforms to the substrate but the 5-layer sheet delaminates, as indicated by the green ellipses in panels (a) and (b). (h) Quantitative agreement between simulation and experiment is evidenced by histograms of the number of wrinkles emanating from each particle, as counted from the images in panels (a) and (b). Error bars correspond to the square root of each count. (i,j) Avoiding wrinkle-like features in geomembranes. The human figure in panel (i) illustrates the scale; panel (j) shows a close-up of the highlighted region, which contains an avoiding pair. Image courtesy Wisconsin Department of Natural Resources38.
Mentions: In those experiments, graphene wrinkles are seen to form pairs that approach each other but do not coalesce17 (see Fig. 1), as also confirmed by atomistic simulations18. Such avoiding wrinkle pairs are not just a curiosity of graphene sheets on patterned substrates, and are found not only in other thin films and possibly even in macroscopic sheets such as geomembranes used to line landfills, an example of which is shown in Fig. 1. Other examples from the physics and engineering literature are listed in Table 1. Furthermore, similar avoiding patterns are widely observed in “en passant” cracks2021, which have a universal shape, independent of material properties21. Despite their ubiquity, the physics of avoiding wrinkle pairs is largely unexplored and a quantitative understanding is lacking of when avoiding pairs form and the morphology they take.

Bottom Line: Although these patterns are part of everyday experience and are important in industry, they are not completely understood.Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates.Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales.

View Article: PubMed Central - PubMed

Affiliation: ISI Foundation, Via Alassio 11/c, 10126 Torino, Italy.

ABSTRACT
On length scales from nanometres to metres, partial adhesion of thin films with substrates generates a fascinating variety of patterns, such as 'telephone cord' buckles, wrinkles, and labyrinth domains. Although these patterns are part of everyday experience and are important in industry, they are not completely understood. Here, we report simulation studies of a previously-overlooked phenomenon in which pairs of wrinkles form avoiding pairs, focusing on the case of graphene over patterned substrates. By nucleating and growing wrinkles in a controlled way, we characterize how their morphology is determined by stress fields in the sheet and friction with the substrate. Our simulations uncover the generic behaviour of avoiding wrinkle pairs that should be valid at all scales.

No MeSH data available.


Related in: MedlinePlus