Solvent–Solvent Correlations across Graphene: The Effect of Image Charges
- Virginia Commonwealth Univ., Richmond, VA (United States); VCU
- Virginia Commonwealth Univ., Richmond, VA (United States)
- Sorbonne Univ., CNRS, Paris (France)
Wetting experiments show pure graphene to be weakly hydrophilic, but its contact angle (CA) also reflects the character of the supporting material. Measurements and Molecular Dynamics simulations on suspended and supported graphene often reveal a CA reduction due to the presence of the supporting substrate. A similar reduction is consistently observed when graphene is wetted from both sides. The effect has been attributed to transparency to molecular interactions across the graphene sheet, however, the possibility of substrate-induced graphene polarization has also been considered. Computer simulations of CA on graphene have so far been determined by ignoring the material’s conducting properties. We improve the graphene model by incorporating its conductivity according to the Constant Applied Potential Molecular Dynamics. Using this method, we compare the wettabilities of suspended graphene and graphene supported by water by measuring the CA of cylindrical water drops on the sheets. The inclusion of graphene conductivity and concomitant polarization effects lead to a lower CA on suspended graphene but the CA reduction is significantly bigger when the sheets are also wetted from the opposite side. The stronger adhesion is accompanied by a profound change in the correlations among water molecules across the sheet. While partial charges on water molecules interacting across an insulator sheet attract charges of the opposite sign, apparent attraction among like charges is manifested across the conducting graphene. The change is associated with graphene polarization, as the image charges inside the conductor attract equally signed partial charges of water molecules on both sides of the sheet. Additionally, by using a non-polar liquid (diiodomethane), we affirm a detectable wetting translucency when liquid-liquid forces are dominated by dispersive interactions. Furthermore, our findings are important for predictive modeling toward a variety of applications including sensors, fuel cell membranes, water filtration, and graphene-based electrode materials in high-performance supercapacitors.
- Research Organization:
- Virginia Commonwealth Univ., Richmond, VA (United States)
- Sponsoring Organization:
- National Science Foundation; USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences & Biosciences Division
- Contributing Organization:
- VCU
- Grant/Contract Number:
- AC02-05CH11231; SC0004406
- OSTI ID:
- 1638266
- Journal Information:
- ACS Nano, Journal Name: ACS Nano Journal Issue: 7 Vol. 14; ISSN 1936-0851
- Publisher:
- American Chemical Society (ACS)Copyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Universal Repulsive Contribution to the Solvent-Induced Interaction Between Sizable, Curved Hydrophobes
Liquids with Lower Wettability Can Exhibit Higher Friction on Hexagonal Boron Nitride: The Intriguing Role of Solid–Liquid Electrostatic Interactions
Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites
Journal Article
·
Tue Jul 26 20:00:00 EDT 2016
· Journal of Physical Chemistry Letters
·
OSTI ID:1525957
Liquids with Lower Wettability Can Exhibit Higher Friction on Hexagonal Boron Nitride: The Intriguing Role of Solid–Liquid Electrostatic Interactions
Journal Article
·
Mon Jan 28 19:00:00 EST 2019
· Nano Letters
·
OSTI ID:1566553
Duality of the Interfacial Thermal Conductance in Graphene-based Nanocomposites
Journal Article
·
Tue Dec 31 23:00:00 EST 2013
· Carbon
·
OSTI ID:1128978