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Femtosecond laser rapid fabrication of large-area rose-like micropatterns on freestanding flexible graphene films.

Shi X, Li X, Jiang L, Qu L, Zhao Y, Ran P, Wang Q, Cao Q, Ma T, Lu Y - Sci Rep (2015)

Bottom Line: This unique hierarchical layering structure of graphene films provides great possibilities for generation of tensile stress during femtosecond laser ablation to roll up the nanoflakes, which contributes to the formation of microflowers.More importantly, this technique enables fabrication of the large-area patterned surfaces at centimeter scales in a simple and efficient way.This study not only presents new insights of ultrafast laser processing of novel graphene-based materials but also shows great promise of designing new materials combined with ultrafast laser surface patterning for future applications in functional coatings, sensors, actuators and microfluidics.

View Article: PubMed Central - PubMed

Affiliation: Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, PR China.

ABSTRACT
We developed a simple, scalable and high-throughput method for fabrication of large-area three-dimensional rose-like microflowers with controlled size, shape and density on graphene films by femtosecond laser micromachining. The novel biomimetic microflower that composed of numerous turnup graphene nanoflakes can be fabricated by only a single femtosecond laser pulse, which is efficient enough for large-area patterning. The graphene films were composed of layer-by-layer graphene nanosheets separated by nanogaps (~10-50 nm), and graphene monolayers with an interlayer spacing of ~0.37 nm constituted each of the graphene nanosheets. This unique hierarchical layering structure of graphene films provides great possibilities for generation of tensile stress during femtosecond laser ablation to roll up the nanoflakes, which contributes to the formation of microflowers. By a simple scanning technique, patterned surfaces with controllable densities of flower patterns were obtained, which can exhibit adhesive superhydrophobicity. More importantly, this technique enables fabrication of the large-area patterned surfaces at centimeter scales in a simple and efficient way. This study not only presents new insights of ultrafast laser processing of novel graphene-based materials but also shows great promise of designing new materials combined with ultrafast laser surface patterning for future applications in functional coatings, sensors, actuators and microfluidics.

No MeSH data available.


(a–c) Ablation size of graphene microflowers versus laser fluence after a single laser pulse ablation. (d–f) Evolution of the graphene microflowers with different pulse numbers at the same laser fluence of 0.2 J/cm2.
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f4: (a–c) Ablation size of graphene microflowers versus laser fluence after a single laser pulse ablation. (d–f) Evolution of the graphene microflowers with different pulse numbers at the same laser fluence of 0.2 J/cm2.

Mentions: The size and shape of the graphene flower can be further controlled by tuning the laser fluence (F) and pulse number (N), respectively. Figure 4 a-c show that under a single pulse irradiation, the size of graphene microflowers increases with the increase of laser fluences, while the morphologies of the flowers approximately remain unchanged. Thus, we can precisely control the size of graphene flowers without changing their geometry by carefully adjusting the laser fluence. Figure 4d-f display the dependence of shape of graphene microflowers on pulse number at a relatively low laser fluence of F = 0.2 J/cm2. At N = 1, several intact and flat graphene flakes were peeled off from the center of the ablated region after a single pulse irradiation, leaving a relative clean and flat surface in the ablation crater (Fig. 4d). The fold of the underlying graphene sheet is clearly visible because the graphene sheets are very thin. As the pulse number increased to N = 3, a new array of graphene nanoflacks were exfoliated from the “new surface” of the graphene film that generated by the previous pulse (Fig. 4e). In this case, most of the ablation area was dominated by the roll-up graphene nanoflacks except the central region. At the pulse number of N = 5, much more graphene nanoflakes were rolled up from center to periphery of the crater, which can dominate the whole area of the ablated region (Fig. 4f). Hence, the “growth” and shape of the microflowers can be controlled by tuning the number of fs laser pulses.


Femtosecond laser rapid fabrication of large-area rose-like micropatterns on freestanding flexible graphene films.

Shi X, Li X, Jiang L, Qu L, Zhao Y, Ran P, Wang Q, Cao Q, Ma T, Lu Y - Sci Rep (2015)

(a–c) Ablation size of graphene microflowers versus laser fluence after a single laser pulse ablation. (d–f) Evolution of the graphene microflowers with different pulse numbers at the same laser fluence of 0.2 J/cm2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4663466&req=5

f4: (a–c) Ablation size of graphene microflowers versus laser fluence after a single laser pulse ablation. (d–f) Evolution of the graphene microflowers with different pulse numbers at the same laser fluence of 0.2 J/cm2.
Mentions: The size and shape of the graphene flower can be further controlled by tuning the laser fluence (F) and pulse number (N), respectively. Figure 4 a-c show that under a single pulse irradiation, the size of graphene microflowers increases with the increase of laser fluences, while the morphologies of the flowers approximately remain unchanged. Thus, we can precisely control the size of graphene flowers without changing their geometry by carefully adjusting the laser fluence. Figure 4d-f display the dependence of shape of graphene microflowers on pulse number at a relatively low laser fluence of F = 0.2 J/cm2. At N = 1, several intact and flat graphene flakes were peeled off from the center of the ablated region after a single pulse irradiation, leaving a relative clean and flat surface in the ablation crater (Fig. 4d). The fold of the underlying graphene sheet is clearly visible because the graphene sheets are very thin. As the pulse number increased to N = 3, a new array of graphene nanoflacks were exfoliated from the “new surface” of the graphene film that generated by the previous pulse (Fig. 4e). In this case, most of the ablation area was dominated by the roll-up graphene nanoflacks except the central region. At the pulse number of N = 5, much more graphene nanoflakes were rolled up from center to periphery of the crater, which can dominate the whole area of the ablated region (Fig. 4f). Hence, the “growth” and shape of the microflowers can be controlled by tuning the number of fs laser pulses.

Bottom Line: This unique hierarchical layering structure of graphene films provides great possibilities for generation of tensile stress during femtosecond laser ablation to roll up the nanoflakes, which contributes to the formation of microflowers.More importantly, this technique enables fabrication of the large-area patterned surfaces at centimeter scales in a simple and efficient way.This study not only presents new insights of ultrafast laser processing of novel graphene-based materials but also shows great promise of designing new materials combined with ultrafast laser surface patterning for future applications in functional coatings, sensors, actuators and microfluidics.

View Article: PubMed Central - PubMed

Affiliation: Laser Micro/Nano Fabrication Laboratory, School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, PR China.

ABSTRACT
We developed a simple, scalable and high-throughput method for fabrication of large-area three-dimensional rose-like microflowers with controlled size, shape and density on graphene films by femtosecond laser micromachining. The novel biomimetic microflower that composed of numerous turnup graphene nanoflakes can be fabricated by only a single femtosecond laser pulse, which is efficient enough for large-area patterning. The graphene films were composed of layer-by-layer graphene nanosheets separated by nanogaps (~10-50 nm), and graphene monolayers with an interlayer spacing of ~0.37 nm constituted each of the graphene nanosheets. This unique hierarchical layering structure of graphene films provides great possibilities for generation of tensile stress during femtosecond laser ablation to roll up the nanoflakes, which contributes to the formation of microflowers. By a simple scanning technique, patterned surfaces with controllable densities of flower patterns were obtained, which can exhibit adhesive superhydrophobicity. More importantly, this technique enables fabrication of the large-area patterned surfaces at centimeter scales in a simple and efficient way. This study not only presents new insights of ultrafast laser processing of novel graphene-based materials but also shows great promise of designing new materials combined with ultrafast laser surface patterning for future applications in functional coatings, sensors, actuators and microfluidics.

No MeSH data available.