Solvent evaporation of spin cast films: ”crust” effects
نویسنده
چکیده
When a glassy polymer film is formed by evaporation, the region near the free surface is polymer rich and becomes glassy first, as noticed long ago by Scriven et al. We discuss the thickness of this ”crust” and the time interval where it is present -before freezing of the whole film. We argue that the crust is under mechanical tension, and should form some cracks. This may be the source of the roughness observed on the final, dry films, when the solvent vapor pressure is high (and leads to thin crusts). PACS numbers: 66.10-x; 68.60-p; 83.80.Rs; 82.70-y. Shortened version of the title:
منابع مشابه
Self-Assembly of Single-Walled Carbon Nanotubes into a Sheet by Drop Drying
Single-walled carbon nanotubes (SWNTs) are currently the focus of extensive interdisciplinary studies because of their unique physical and chemical properties and potential electronic applications, for example, in making sensors and fieldemission devices. Processing of SWNT-based materials into engineered macroscopic materials is still in its infancy; the most successful methods so far have bee...
متن کاملElongated phase separation domains in spin-cast polymer blend thin films characterized using a panoramic image.
Polymer thin films with micro/nano-structures can be prepared by a solvent evaporation induced phase separation process via spin-casting a polymer blend, where the elongated phase separation domains are always inevitable. The striation defect, as a thickness nonunifomity in spin-cast films, is generally coexistent with the elongated domains. Herein, the morphologies of polymer blend thin films ...
متن کاملSlow Relaxation of Spin - Cast Poly ( methyl methacrylate ) Confined in Thin Films
Although the volume relaxation of bulk homopolymer glasses is thoroughly understood, many questions remain about the volume relaxation of polymers cast from solvent. Furthermore, in polymer thin films, the possible effects of confinement, surfaces and interfaces on relaxation are largely unexplored. Measurements of the film thickness of spin-cast poly(methyl methacrylate) thin films over extend...
متن کاملSome insights into the structural relaxation of spin- cast, glassy polymer thin films
The widespread use of thin films in a range of applications and industries, from coatings, inks and lithography to nano-imprinting, optoelectronics, and memory devices , has made the understanding of thin films, particularly the changes induced by structural relaxation and solvent evaporation, very important. There is a need to know if a film will change in dimensions after its deposition and h...
متن کاملSpin coating of thin and ultrathin polymer films
The spin coating of thin (> 200 nm thick) and ultrathin (< 200 nm thick) polymer films is examined in several solvents of varying volatility over a broad range of polymer solution concentrations and spin speeds. Experimentally measured film thicknesses are compared with a simple model proposed by Bornside, Macosko, and Scriven, which predicts film thickness based on the initial properties of th...
متن کامل