Evolution of Surface Morphology of Spin-Coated Poly(Methyl Methacrylate) Thin Films

Abstract

The morphology of sub-micron poly(methyl methacrylate) films coated to glass supports by spin coating from toluene is examined using surface profilometry. Wrinkled surfaces with local quasi-sinusoidal periodicity were seen on the surfaces of films with thicknesses of larger than 75 nm. The surface wrinkles had large aspect ratios with wavelengths in the tens of microns and amplitudes in the tens of nanometers. Wrinkles that formed during spin-coating are attributed to surface perturbations caused by Rayleigh–Bénard–Marangoni convective instabilities. The effects of film thickness, coating solution concentration, and drying rate on the thin film surface morphology are investigated. The results can be used to prepare surfaces with controlled morphology, either smooth or with periodic wrinkles.

Interfacial Effects of the Photophysics of Rhodamine 6G Ultra-Thin Films on a Poly(methylmethacrylate) Surface

“…We previously reported that the surface morphology of the PMMA films formed by spin coating can have a quasi-periodic structure. , These surface deformations are vitrified Rayleigh–Bénard–Marangoni convective instabilities that arise during the film drying portion of the spin coating process . For very thin films of thickness less than 75 nm, the surfaces were nearly flat.…”

“…PMMA is deposited by spin coating on a cleaned glass surface. By varying the spin coating variables, the thickness and surface morphology of the PMMA can be controlled. − PMMA is unique such that periodic surface structures (wrinkles, striations, or corrugations) can be with wavelengths in the range of tens of μm and amplitudes in the range of tens of nm. Unlike PVDF, the PMMA surface roughness can be controlled, which allows a comparison between the two polymers.…”

Modeling Solution Drying by Moving a Liquid-Vapor Interface: Method and Applications

“…Therefore, the method cannot be directly applied to systems where the liquid-vapor interface develops instabilities during evaporation. For example, when a spin-coated polymeric film is dried, it may develop Rayleigh–Bénard–Marangoni convective instabilities that cause the evolution of surface morphology of the film [ 42 ]. To capture these effects, the moving interface method needs to be extended to include a model for the liquid-vapor interface that allows the interface to deform and exhibit various instabilities during the drying process.…”

“…To model the drying process of a soft matter solution, a key challenge is the treatment of the solvent. To capture factors that may be important in an evaporation process, such as hydrodynamic interactions between solutes [ 30 , 34 ], evaporation-induced flow in the solution (e.g., capillary flow in an evaporating droplet showing the coffee-ring effect) [ 39 ], and instabilities during drying including Rayleigh-Bénard and Bénard-Marangoni instabilities [ 8 , 40 , 41 , 42 ], it is ideal to include the solvent explicitly in a computational model [ 15 , 24 , 25 , 30 , 31 , 32 , 34 , 36 , 37 , 38 ]. However, such models are computationally extremely expensive as the solvent particles significantly outnumber the solutes at realistic volume fractions.…”

Atmospheric plasma treatment to improve the surface properties of P3HB coating. A study of the influence of substrate roughness

“…However, it is a dynamic process in which evaporation and temperature can cause certain instabilities in the fluid and affect the roughness of the coating surface, especially if the roughness of the substrate is high or low. 21,22 For this reason, P3HB coatings were performed by the spin coating method on stainless steel substrates with different roughness in this work. The objective is to analyze the surface properties of the coatings resulting from the various mechanical interlocking.…”