Abstract
ABSTRACTMolecular dynamics and steered molecular dynamics (SMD) simulations are used to investigate the underwater adhesive forces of 1, 2-dichloroethane (DCE) on ionic and non-ionic self-assembled monolayers (SAMs) grafted on Au (111). The non-ionic SAMs containing hydroxyl group include ethanolamine-terminated SAM (ETA-SAM), dopamine-terminated SAM (DOPA-SAM), hydroxyl-terminated SAM (OH-SAM) and oligo(ethylene glycol)-terminated SAM (OEG-SAM); the ionic SAMs contain mixed-charged zwitterionic SAM and zwitterionic phosphorylcholine-terminated SAM . Simulation results show that the order of underwater oleophobicity of SAMs is OEG-SAM < ETA-SAM < OH-SAM < DOPA-SAM < < , while the order of underwater DCE oil droplet adhesion forces on different SAMs is < < ETA-SAM < DOPA-SAM < OH-SAM < OEG-SAM. The ionic SAMs show stronger underwater oleophobicity and lower oil adhesion than non-ionic SAMs. Generally, a more underwater oleophobic surface is less adhesive. The underwater oil droplet desorption behaviours on ionic and non-ionic SAMs are also different. With the oil droplet being pulled away from ionic SAMs, the oil contact lines gradually shortened and disappeared finally; whereas the oil contact lines on non-ionic SAMs almost kept an initial state even the main part of oil droplet separated from the SAMs. This work systematically proved that a zwitterionic surface was less underwater oil adhesive than a non-ionic surface and provided a new insight for their oil desorption behaviours. The above results will be helpful for the design of underwater oleophobic surfaces with tuneable adhesion.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.