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Wettability of partially suspended graphene.

Ondarçuhu T, Thomas V, Nuñez M, Dujardin E, Rahman A, Black CT, Checco A - Sci Rep (2016)

Bottom Line: We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate.Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions.By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

View Article: PubMed Central - PubMed

Affiliation: Nanosciences group, CEMES-CNRS, 29 rue Jeanne Marvig, Toulouse 31055, France.

ABSTRACT
The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

No MeSH data available.


Related in: MedlinePlus

Plot of cos θGS as a function of cos θS for the three different systems schematized in the above insets: fully supported graphene in red, partially suspended on air in green and partially suspended on water in blue.The solid black line is a linear fit of the experimental data. Grey dashed line is the cos θGS = cos θS line whereas the black cross marks the experimental wetting angle on HOPG.
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f5: Plot of cos θGS as a function of cos θS for the three different systems schematized in the above insets: fully supported graphene in red, partially suspended on air in green and partially suspended on water in blue.The solid black line is a linear fit of the experimental data. Grey dashed line is the cos θGS = cos θS line whereas the black cross marks the experimental wetting angle on HOPG.

Mentions: where γ is the surface tension of water. Figure 5 gathers the measurements performed on all the fabricated samples which were categorized in three types, namely supported graphene (red open dots), graphene partially suspended on air (green open dots) and water (blue open dots). Remarkably, the data show that all experimental results collapse on a straight line except for data points in a narrow region where cos θS ≅ 1. The scattering of data in this region is likely due to the larger density of graphene defects on hydrophilic nanocone textures (ϕd ~ 8%).


Wettability of partially suspended graphene.

Ondarçuhu T, Thomas V, Nuñez M, Dujardin E, Rahman A, Black CT, Checco A - Sci Rep (2016)

Plot of cos θGS as a function of cos θS for the three different systems schematized in the above insets: fully supported graphene in red, partially suspended on air in green and partially suspended on water in blue.The solid black line is a linear fit of the experimental data. Grey dashed line is the cos θGS = cos θS line whereas the black cross marks the experimental wetting angle on HOPG.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4829856&req=5

f5: Plot of cos θGS as a function of cos θS for the three different systems schematized in the above insets: fully supported graphene in red, partially suspended on air in green and partially suspended on water in blue.The solid black line is a linear fit of the experimental data. Grey dashed line is the cos θGS = cos θS line whereas the black cross marks the experimental wetting angle on HOPG.
Mentions: where γ is the surface tension of water. Figure 5 gathers the measurements performed on all the fabricated samples which were categorized in three types, namely supported graphene (red open dots), graphene partially suspended on air (green open dots) and water (blue open dots). Remarkably, the data show that all experimental results collapse on a straight line except for data points in a narrow region where cos θS ≅ 1. The scattering of data in this region is likely due to the larger density of graphene defects on hydrophilic nanocone textures (ϕd ~ 8%).

Bottom Line: We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate.Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions.By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

View Article: PubMed Central - PubMed

Affiliation: Nanosciences group, CEMES-CNRS, 29 rue Jeanne Marvig, Toulouse 31055, France.

ABSTRACT
The dependence of the wettability of graphene on the nature of the underlying substrate remains only partially understood. Here, we systematically investigate the role of liquid-substrate interactions on the wettability of graphene by varying the area fraction of suspended graphene from 0 to 95% by means of nanotextured substrates. We find that completely suspended graphene exhibits the highest water contact angle (85° ± 5°) compared to partially suspended or supported graphene, regardless of the hydrophobicity (hydrophilicity) of the substrate. Further, 80% of the long-range water-substrate interactions are screened by the graphene monolayer, the wettability of which is primarily determined by short-range graphene-liquid interactions. By its well-defined chemical and geometrical properties, supported graphene therefore provides a model system to elucidate the relative contribution of short and long range interactions to the macroscopic contact angle.

No MeSH data available.


Related in: MedlinePlus