Suppression of surface pattern formation in spin-coated polymer films by the addition of polydimethylsiloxane-grafted silica nanoparticles

Polydimethylsiloxane (PDMS)-grafted nanoparticles and PDMS were added, respectively, to inhibit the dewetting of polymer films and the formation of surface patterns in spin coating. Uniform and flat films were successfully achieved with the addition of PDMS-grafted silica nanoparticles or PDMS. Time-of-flight secondary ion mass spectrometry depth profiling indicated that PDMS-grafted silica nanoparticles and PDMS preferentially segregated to the surface. A high concentration of bromine end groups was observed at the interface. The surface layer of PDMS or PDMS-grafted silica nanoparticles can decrease the surface tension of the polymer solutions and reduce the evaporation rates of the solvents, providing more time for the bromine end groups to anchor themselves at the silicon substrates.