Morphology Control of Polymer thin Films

A large number of studies revealed that various physical properties of thin polymer films strongly deviate from those in the three-dimensional bulk state when the film thickness is less than the unperturbed dimension of the polymer chain [8-15]. Polymer chains in the bulk typically take on a so-called random coil conformation, where the physical orientation of each repeat unit along the chain s backbone is essentially uncorrelated with the orientations of the chain s other repeat units. In thin films, the confinement of molecules between two interfaces (solid substrate and free surface) reduces the degree of freedom of the polymer chains such that the random coil conformation will be modified due to the spatial confinement and a transition from the 3D to the 2D case will take place with decreasing film thicknesses [16,17]. The conformation of single polymer chain and the interactions between the polymer chain and the interface are crucial factors to determine the characteristic properties of the thin film. Therefore, polymers in thin-film state have attracted great attention and have been extensively studied by many researchers [18-21]. 

Different phenomena happen when some liquid is dropped onto a solid surface. In case the amount of liquid is large, the liquid can fully cover the soUd surface even if the liquid does not like the solid surface. And the thick liquid film remains stable due to the effect of gravity. When the thickness of the 

Polymer Morphology Principles, Characterization, and Processing, First Edition. Edited by Qipeng Guo. 2016 John Wiley Sons, Inc. Published 2016 by John Wiley Sons, Inc. 

In practice, liquids (e.g., polymers discussed here) are normally forced to spread onto solid surfaces, including onto nonwettable surfaces, using techniques like spin coating. The resulted film is in a nonequilibrium state. If the thickness of the polymer film is smaller than the capillary length of the liquid, A ap, which is defined by A ap = with 

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The Morphology Control of Polymer Thin Films via the Spin-Coating Process... 

Li X, Han Y, An L. Surface morphology control of immiscible polymer-blend thin films. Polymer 2003 44 8155-8165. 

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