Formation of a large-area monolayer of polystyrene film via the spin-coating method

Abstract

The self-assembly methods, an inexpensive and high throughput technique capable of producing nanostructure arrays, relies on the formation on a monolayer of self-assembled nanospheres. This paper reports on the formation of large-areas monolayer polystyrene particles ~150 nm in diameter onto monocrystalline Si (100) substrates by using the spin-coating method. In this method, the quality of the deposited monolayer is determined by the balance between spinning and solvent evaporation, accounted by two different forces, the centrifugal force and viscous shearing force, and their interplay. The key process parameters which influence the deposition process and determine the properties of polystyrene monolayers such as the spinning rate, time and concentration of PS particles in the solution were studied. By varying the experimental conditions in different steps the films quality can be easily improved and the optimized experimental parameters were achieved. A homogenous and well-ordered PS monolayer with a high surface coverage of ~94 % was formed on a large-area substrate of 1 cm ?1 cm at specific conditions of a 2000 rpm spinning rate, 2 wt. % polystyrene solution concentration and 210 s duration of the spinning process. We conclude that this method can be useful in a variety of applications since it offers a stable and controllable approach to the fabrication of monolayer polystyrene films on a large-scale.