Fig. 6: Plant protein film for coating with barrier function.
a Schematic illustration of the coating process. A piece of paperboard was dipped in the SPI solution and pulled out slowly, leading to the formation of a gel coating its surface. The paperboard was allowed to dry at room temperature to achieve an anhydrous thin layer of coating. b Optical images of paperboards before and after SPI coating. c, d SEM images of paperboard without (c) and with (d) SPI coating. Scale bars represent 500 μm. e Water uptake of the treated and untreated paperboards measured over 30 min studied through gravimetry. The indicated error bars represent the s.d. of the average of three independent measurements. f, g Colour changes of CoCl2-stained paperboards before and after immersing in water for 5 s (Supplementary Movie 1). The paperboard was prepared without (f) and with (g) SPI coating, respectively.
