The film formation dynamics in spin coating

Ohara, Taku; Matsumoto, Yoichiro; Ohashi, Hideo

doi:10.1063/1.857520

Cited by 65 publications

(49 citation statements)

References 18 publications

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“…3b-3c are unable to describe the dynamics of spinup when inertial effects are important (Higgins, 1986;Rehg and Higgins, 1988). Recently, Ohara et al (1989) proposed Eqs. 2-5 as a model of spin coating, but they did not consider inertial effects as these effects were apparently unimportant in their study.…”

Section: Mathematical Formulationmentioning

confidence: 98%

Spin coating of colloidal suspensions

Rehg

Higgins

1992

AIChE Journal

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Section: Mathematical Formulationmentioning

confidence: 98%

Spin coating of colloidal suspensions

Rehg

Higgins

1992

AIChE Journal

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“…While the dynamics of spin-coating has been studied extensively and quantitatively in simple one-component fluids 8,9 as well as in polymer solutions, 10,11 the study of the dynamics of colloid spin-coating has been limited to numerical studies of thinning rates. 12 A recent work demonstrates that spin-coating flows (in the absence of evaporation) control the local stress profiles, and drive crystallization when the Peclet number exceeds a critical value.…”

mentioning

confidence: 99%

Dynamics of Crystal Structure Formation in Spin-Coated Colloidal Films

Giuliani

González-Viñas

Poduska

et al. 2010

J. Phys. Chem. Lett.

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The spin-coating of colloidal suspensions is an inherently nonequilibrium process that gives rise to highly reproducible, but polycrystalline, films with different symmetries depending on experimental parameters. In this study, we explore the transient dynamics of evaporative colloid spin-coating for the first time, via a combination of high-speed imaging, atomic force microscopy, static photography, and scanning electron microscopy. As the wet colloidal film thins and dries, we observe several symmetry transitions, while at the same time remarkably, the thinning rate (in nondimensional time units) collapses to one universal curve for all rotation rates. We correlate static and dynamic measures of crossovers in ordering regimes, and obtain an estimate of the evaporation rate in the late stage of drying. We conclude that the thinning dynamics controls the local volume fraction and stress profiles, which in turn drives the structural transitions. SECTION Macromolecules, Soft Matter C olloidal self-assembly is a facile and promising method for making photonic crystals, 1 but the control of defects is a challenge. Nonequilibrium approaches to colloidal self-assembly are likely crucial to the making of large-area colloidal crystals.2,3 Colloid spin-coating has recently emerged as a highly robust and reproducible nonequilibrium method to make multilayer colloidal crystalline films. [4][5][6] However, in spite of its robustness, the spin-coating route to colloidal crystals is fraught with challenges. The highly uniform structural colors exhibited by these films have been shown to arise from a polycrystal where different crystallites exhibit longrange orientational order. 7 In order to develop strategies to produce crystals with a greater degree of translational order, a deeper understanding of the dynamical mechanisms of structure formation is required.While the dynamics of spin-coating has been studied extensively and quantitatively in simple one-component fluids 8,9 as well as in polymer solutions, 10,11 the study of the dynamics of colloid spin-coating has been limited to numerical studies of thinning rates.12 A recent work demonstrates that spin-coating flows (in the absence of evaporation) control the local stress profiles, and drive crystallization when the Peclet number exceeds a critical value. 6 Two questions that have remained unaddressed;how the dynamics interlinks with the emergence of different symmetries, and the role played by evaporation;are the focus of the experiments reported here.We begin with our observations of the transient dynamics. Using high-speed imaging and the lighting configuration A (Figure 6), we are sensitive to changes in long-range orientational order via the appearance of symmetries in the optical reflections. In all experiments (at varying rotation speeds) common dynamical features are observed in the fluid phase. While the results presented here pertain to experiments using methyl ethyl ketone (MEK) as solvent, similar results were found with acetone as solvent. This phase...

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“…Spin coating is one of the most common techniques used for depositing uniform thin films from a few nanometers to a few micrometers in thickness on flat substrates [64].…”

Section: Spin Coatingmentioning

confidence: 99%