Oil-Repellent Hydrophilic Surfaces for Self-Cleaning Anti-Fog Applications by
John Howarter and Jeffrey P. Youngblood
Shown below is a schematic of tethered polymer chains in both the mushroom and brush regimes. We modify surfaces with polymer brushed using the grafting to method, in which entire block co-polymers are attached to the surface either by chemical or physical adsorption. At extremely low grafting densities the polymer chains exist in a mushroom-like regime taking on the shape of their hydrodynamic volume. As grafting density increases polymer chain volume is constrained resulting in an elongated brush-like regime.
Silica filter modified with polymer brushes. Oil is unable to pass through as shown, water on the other hand passes through unimpeded.