Controlling the Accumulation of Water at Oil-Solid Interfaces with Gradient Coating
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
In this work, we demonstrate a strategy to control the accumulation of water in the oil–solid interface using a gradient coating. Gradient chemistry on glass surface is created by vapor diffusion of organosilanes, leading to a range of contact angles from 110 to 20°. Hexadecane is placed on the gradient substrate as an oil layer, forming a “water/hexadecane/gradient solid substrate” sandwich structure. During incubation, water molecules spontaneously migrate through the micrometer-thick oil layer and result in the formation of micrometer-sized water droplets at the oil–solid interface. It turns out that water droplets at more hydrophobic regions tend to be closer to a regular spherical shape, which is attributed to their higher contact angle with the hydrophobic substrate. However, along the gradient from hydrophobic to hydrophilic, the water droplets gradually form more irregular shapes, as hydrophilic surfaces pin the edges of droplets to form a distorted morphology. It indicates that more hydrophilic surfaces containing more Si–OH groups lead to a higher electrostatic interaction with water and a higher growth rate of interfacial water droplets. This work provides further insights into the mechanism of spontaneous water accumulation at oil–solid interfaces and assists in the rational design for controlling such interfacial phenomenon.
Date Issued
2017-07-13
Date Acceptance
2017-06-18
Citation
Journal of Physical Chemistry B, 2017, 121 (27), pp.6766-6772
ISSN
1520-5207
Publisher
American Chemical Society
Start Page
6766
End Page
6772
Journal / Book Title
Journal of Physical Chemistry B
Volume
121
Issue
27
Copyright Statement
Copyright © 2017 American Chemical Society
Subjects
Science & Technology
Physical Sciences
Chemistry, Physical
Chemistry
LIQUID INTERFACES
CONTACT ANGLES
ICE NUCLEATION
SILICA SURFACE
DROPLETS
NANOPARTICLES
LUBRICATION
CAPILLARITY
FABRICATION
DETACHMENT
Publication Status
Published