Process Optimization of Ultrasonic Spray Coating of Polymer Films

详细信息    查看全文

• 作者：Sanjukta Bose ; Stephan S. Keller ; Tommy S. Alstr酶m ; Anja Boisen ; Kristoffer Almdal
• 刊名：Langmuir
• 出版年：2013
• 出版时间：June 11, 2013
• 年：2013
• 卷：29
• 期：23
• 页码：6911-6919
• 全文大小：472K
• 年卷期：v.29,no.23(June 11, 2013)
• ISSN：1520-5827

文摘

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 渭m) 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, 鈥渄ry鈥?and 鈥渨et鈥? 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.