How do drying methods affect quality of films? Drying of polymer solutions under hot-air flow or infrared heating with comparable evaporation rates

Abstract

Wrinkles formed during the drying of polymer films by hot-air flow but not when drying by infrared irradiation, even though drying rates were comparable. The top surface was hotter than the bottom during hot-air drying. Conversely, the temperatures of the top and bottom surfaces were very similar when drying by infrared irradiation. We also examined uniform heating with faster and slower drying rates using drying with combined infrared irradiation and air flow (hot or room temperature). Wrinkles formed in both cases. This demonstrated the negative effect of air flow. Features and mechanism of each drying method are discussed.

Keywords:

• Coatings
• heat and mass transfer
• infrared drying
• polymer drying
• mathematical modeling
• transport phenomena

Conflict of interest

The authors declare the following competing financial interest(s): Three of the authors T. Kinnan, Y. Kondo, and M. Aoki are employees of NGK and this work was funded by NGK.

Acknowledgements

We thank S. Koga and K. Abe, Tokyo University of Agriculture and Technology, for their technical supports for sample preparation and observation of films. We thank Aidan G. Young, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.

Additional information

Funding

This work was financially supported by NGK INSULATORS, Japan.