Science and Functions of Densely Grafted solid Surfaces

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We studied the structure, properties, and functions of high-density polymer brushes from a range of angles to obtain the following new findings : (1)High-density dry brushes have higher glass transition temperatures and (2)higher compression moduli than equivalent spin-cast films, and (3)they are immiscible with homologous free polymers. (4) While high-density brushes swollen in a good solvent also have high compression moduli, (5)they exhibit extremely low friction coefficients. (6)Silica monolith columns with high-density poly (methyl methacrylate) (PMMA) brushes grafted on their surfaces show a size-exclusion effect by the brush layer. (7)Surfaces with high-density poly (hydroxyethyl methacrylate) (PHEMA) brushes effectively prevent adsorption and adhesion of protein molecules. (8)Gold and silica nanoparticles dispersed in a good solvent for the brush polymer form 2- and 3-dimensionally ordered structures with a very large particle-to-particle nearest distance, even comparable to the full length of the graft chains. These results are specific to high-density brushes, but not to medium-to-low density brushes, and suggest possible applications of high-density polymer brushes to various fields of science and technology.