title: Correlation of nanoscale behaviour of forces and macroscale surface wettability.
abstract: In this manuscript, we demonstrate a method based on atomic force microscopy which enables local probing of surface wettability. The maximum pull-off force, obtained from force spectroscopy shows a remarkable correlation with the macroscopically observed water contact angle, measured over a wide variety of surfaces starting from hydrophilic, all the way through to hydrophobic ones. This relationship, consequently, facilitates the establishment of a universal behaviour. The adhesion forces scale with the polar component of surface energy. However, no such relation could be established with the dispersive component. Hence, we postulate that the force(s) which enable us to correlate the force spectroscopy data measured on the nanoscale to the macroscopic contact angle are primarily arising from electrostatic-dipole-dipole interactions at the solid-liquid interface. London forces play less of a role. This effect in is line with density functional theory (DFT) calculations suggesting a higher degree of hydroxylation of hydrophilic surfaces. This result shows that molecular simulations and measurements on an atomic scale can be extrapolated to macroscopic surface wetting problems.
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Abhimanyu
authors: A
authors: Rana
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456.
authors: Abhijeet
authors: A
authors: Patra
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Meenakshi
authors: M
authors: Annamalai
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Amar
authors: A
authors: Srivastava
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Siddhartha
authors: S
authors: Ghosh
authors: Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. shaohorn@mit.edu.
authors: Kelsey
authors: K
authors: Stoerzinger
authors: Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. shaohorn@mit.edu.
authors: Yueh-Lin
authors: YL
authors: Lee
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456.
authors: Saurav
authors: S
authors: Prakash
authors: Department of Electrical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583.
authors: Reuben Yeo
authors: RY
authors: Jueyuan
authors: Department of Electrical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583.
authors: Partho S
authors: PS
authors: Goohpattader
authors: Department of Electrical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583.
authors: Nalam
authors: N
authors: Satyanarayana
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Kalon
authors: K
authors: Gopinadhan
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456.
authors: Michal M
authors: MM
authors: Dykas
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456.
authors: Kingshuk
authors: K
authors: Poddar
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Surajit
authors: S
authors: Saha
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Tarapada
authors: T
authors: Sarkar
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg.
authors: Brijesh
authors: B
authors: Kumar
authors: Department of Electrical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583.
authors: Charanjit S
authors: CS
authors: Bhatia
authors: Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. shaohorn@mit.edu and U.S. Department of Energy, National Energy Technology Laboratory, 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, PA 15236-0940, USA.
authors: Livia
authors: L
authors: Giordano
authors: Electrochemical Energy Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139, USA. shaohorn@mit.edu.
authors: Yang
authors: Y
authors: Shao-Horn
authors: NUSNNI-NanoCore, National University of Singapore (NUS), Singapore 117411. venky@nus.edu.sg and NUS Graduate School for Integrative Sciences and Engineering (NGS), National University of Singapore (NUS), Singapore 117456 and Department of Electrical Engineering, National University of Singapore (NUS), 4 Engineering Drive 3, Singapore 117583 and Department of Physics, Faculty of Science, National University of Singapore (NUS), Singapore 117551 and Department of Materials Science and Engineering, National University of Singapore (NUS), Singapore 117575.
authors: T
authors: T
authors: Venkatesan