Polymer brushes are becoming increasing popular in the chemical literature, because scientists can control their chemical configuration, density, architecture, and thickness down to nanoscale precision with even simple laboratory setups. A polymer brush is made up of a layer of polymers attached to a substrate surface at one end with the other end dangling into a solvent. In a suitable solvent, the polymer chains stretch away from the surface due to both steric and osmotic repulsion between the chain segments. In an inadequate solvent, however, the polymer chains collapse due to enough interior free space after desolvation. This unique class of materials exhibit interesting physicochemical properties at interfaces and have numerous applications from sensing to surface/interface property control.