title: Surface energy and wettability of van der Waals structures.
abstract: The wetting behaviour of surfaces is believed to be affected by van der Waals (vdW) forces; however, there is no clear demonstration of this. With the isolation of two-dimensional vdW layered materials it is possible to test this hypothesis. In this paper, we report the wetting behaviour of vdW heterostructures which include chemical vapor deposition (CVD) grown graphene, molybdenum disulfide (MoS2) and tungsten disulfide (WS2) on few layers of hexagon boron nitride (h-BN) and SiO2/Si. Our study clearly shows that while this class of two-dimensional materials are not completely wetting transparent, there seems to be a significant amount of influence on their wetting properties by the underlying substrate due to dominant vdW forces. Contact angle measurements indicate that graphene and graphene-like layered transitional metal dichalcogenides invariably have intrinsically dispersive surfaces with a dominating London-vdW force-mediated wettability.
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org.
authors.forename: Meenakshi
authors.initials: M
authors.lastname: Annamalai
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org and Department of Electrical and Computer Engineering, National University of Singapore (NUS), Singapore 117583.
authors.forename: Kalon
authors.initials: K
authors.lastname: Gopinadhan
authors.affiliation: Nanoelectronic Science and Engineering Laboratory, Department of Advanced Materials Science & Engineering, School of Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea. kimsw1@skku.edu and SKKU Advanced Institute of Nanotechnology (SAINT), Center for Human Interface Nanotechnology (HINT), Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Sang A
authors.initials: SA
authors.lastname: Han
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org and Department of Physics, Faculty of Science, National University of Singapore (NUS), Singapore 117551.
authors.forename: Surajit
authors.initials: S
authors.lastname: Saha
authors.affiliation: Nanoelectronic Science and Engineering Laboratory, Department of Advanced Materials Science & Engineering, School of Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea. kimsw1@skku.edu.
authors.forename: Hye Jeong
authors.initials: HJ
authors.lastname: Park
authors.affiliation: Nanoelectronic Science and Engineering Laboratory, Department of Advanced Materials Science & Engineering, School of Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea. kimsw1@skku.edu.
authors.forename: Eun Bi
authors.initials: EB
authors.lastname: Cho
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org.
authors.forename: Brijesh
authors.initials: B
authors.lastname: Kumar
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456.
authors.forename: Abhijeet
authors.initials: A
authors.lastname: Patra
authors.affiliation: Nanoelectronic Science and Engineering Laboratory, Department of Advanced Materials Science & Engineering, School of Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea. kimsw1@skku.edu and SKKU Advanced Institute of Nanotechnology (SAINT), Center for Human Interface Nanotechnology (HINT), Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Sang-Woo
authors.initials: SW
authors.lastname: Kim
authors.affiliation: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg gopinadhan@iitkalumni.org and Department of Electrical and Computer Engineering, National University of Singapore (NUS), Singapore 117583 and Department of Physics, Faculty of Science, National University of Singapore (NUS), Singapore 117551 and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456 and Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore 117575.
authors.forename: T
authors.initials: T
authors.lastname: Venkatesan