Morphological properties of airbrush spray-deposited enzymatic cellulose thin films

• DOI: 10.1007/s11998-018-0089-9
• Publication Date: 2018-05-15T16:58:51Z
• Authors: Wiebke Ohm; André Rothkirch; Pallavi Pandit; Volker Körstgens; Peter Müller-Busc...; Ramiro Rojas; Shun Yu; Calvin J. Brett; Daniel L. Söderberg; Stephan V. Roth
• Keywords: info:eu-repo/classification/ddc/670; 670; 01 natural sciences; ddc:; 0104 chemical sciences

Journal of coatings technology 15(4), 759 - 769 (2018). doi:10.1007/s11998-018-0089-9<br/>Published by Springer Nature, Cham<br/>We investigate the layer formation of enzymatic cellulose by airbrush spray coating on silicon oxide surfaces. 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. The crystallinity remains unchanged; the nanoscale structures show three distinct sizes. Our 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.<br/>