title: Note: Automatic layer-by-layer spraying system for functional thin film coatings.
abstract: In this study, we have constructed an automatic spray machine for producing polyelectrolyte multilayer films containing various functional materials on wide substrates via the layer-by-layer (LbL) assembly technique. The proposed machine exhibits advantages in terms of automation, process speed, and versatility. Furthermore, it has several features that allow a fully automated spraying operation, such as various two-dimensional spraying paths, control of the flow rate and operating speed, air-assist fan-shaped twin-fluid nozzles, and an optical display. The robot uniformly sprays aqueous mixtures containing complementary (e.g., oppositely charged, capable of hydrogen bonding, or capable of covalent bonding) species onto a large-area substrate. Between each deposition of opposite species, samples are spray-rinsed with deionized water and blow-dried with air. The spraying, rinsing, and drying areas and times are adjustable by a computer program. Twenty-bilayer flame-retardant thin films were prepared in order to compare the performance of the spray-assisted LbL assembly with a sample produced by conventional dipping. The spray-coated film exhibited a reduction of afterglow time in vertical flame tests, indicating that the spray-LbL technique is a simple method to produce functional thin film coatings.
authors.affiliation: Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do 449-728, South Korea.
authors.forename: Seongmin
authors.initials: S
authors.lastname: Seo
authors.affiliation: School of Mechanical Engineering, Chung-Ang University, Seoul 156-756, South Korea.
authors.forename: Sangmin
authors.initials: S
authors.lastname: Lee
authors.affiliation: Department of Mechanical Engineering, Myongji University, Yongin-si, Gyeonggi-do 449-728, South Korea.
authors.forename: Yong Tae
authors.initials: YT
authors.lastname: Park