Polymer brushes composed of macromolecules grafted to a substrate represent a unique way to modify surface properties such as lubrication, tack, and adhesion.
Typically, a thin polymer layer is obtained in the range of several ten to hundred nanometers for synthetic polymers and up to micrometers for biopolymers. Due to the unique feature of long flexible polymers, which combine liquid- and solid-state properties, such brush-layers form surface-bound liquid phases composed of the polymer and solvent, and may contain cosolvents, cosolutes, counter-ions and salt-ions and other molecules. Combing these properties in addition to polymer composition and architecture spawns a plethora of possible applications. On the other hand, the well-defined structure of the brush where each macromolecule is bound to the surface makes the system attractive for theoretical approaches and computer simulations.
Challenges for ongoing and future research are the understanding of the roles of chain architecture, chemical sequences, electrostatic interactions, volume phase transitions induced by solvent mixtures, the step from macroscopic flat substrates to other geometries and non-equilibrium properties of brushes.