Process Optimization of Ultrasonic Spray Coating of Polymer Films

In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickne...

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Bibliographic Details
Published in:Langmuir 2013-06, Vol.29 (23), p.6911-6919
Main Authors: Bose, Sanjukta, Keller, Stephan S, Alstrøm, Tommy S, Boisen, Anja, Almdal, Kristoffer
Format: Article
Language:English
Subjects:
Applied sciences
Exact sciences and technology
Forms of application and semi-finished materials
Particle Size
Polymer industry, paints, wood
Polymers - chemistry
Sheets and films
Sonication
Surface Properties
Technology of polymers
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Summary:In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, “dry” and “wet”. The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (d,l-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films.
ISSN:0743-7463
1520-5827
DOI:10.1021/la4010246