Polymer brush electrets

The charge storage properties of polymer brushes are reported for the first time. Poly(methyl methacrylate) (PMMA) brushes are explored as electrets to store electrostatic charges. Micrometer- and nanometer-scale patterns of electrostatic charges are successfully fabricated on planar and non-planar PMMA brush films by means of conductive microcontact printing and atomic force microscope lithography, where the charge storage density and stability are studied in detail with Kelvin force microscopy. Importantly, because PMMA brushes are chemically tethered on the substrate, their charge storage properties can be studied in various organic solvents, in which their bulk counterparts will be dissolved. It is found that patterned charges on PMMA brushes are stable enough in organic media, such as hexane and toluene, for guiding the assembly of Au nanoparticles in organic media and the dewetting of polymer thin films with solvent annealing. The electrets properties shall add a new dimension of functionality, apart from the conventional chemical and physical properties, to polymer brushes for a wide range of applications in materials science, nanotechnology, and electronic devices. Poly(methyl methacrylate) (PMMA) brushes are demonstrated for the first time as electrets. Micro/nano patterns of electrostatic charges are fabricated on PMMA brushes by conductive microcontact printing and AFM lithography. The electrostatic charges on PMMA brushes are stable enough in organic solvents for guiding the assembly of nanoparticles and directing the dewetting of bulk polymer thin films.