Morphological properties of airbrush spray-deposited enzymatic cellulose thin films
The layer structure and morphology of enzymatic cellulose films in the thickness range between 86 nm and 2.1 µm is determined as a function of the spray coating procedures. For each spray coating step, layer buildup, surface topography, crystallinity as well as the nanoscale structure are probed with atomic force microscopy and surface-sensitive X-ray scattering methods. Without intermittent drying, the film thickness saturates; with intermittent drying, a linear increase in layer thickness with the number of spray pulses is observed. A closed cellulose layer was always observed.
Three distinct sizes of nanoscale structures
The crystallinity remains unchanged; the nanoscale structures show three distinct sizes. The results indicate that the smallest building blocks increasingly contribute to the morphology inside the cellulose network for thicker films, showing the importance of tailoring the cellulose nanofibrils. For a layer-by-layer coating, intermittent drying is mandatory.
The study is published in: Journal of Coatings Technology and Research July 2018, Volume 15, Issue 4, pp 759–769.