Fig. 4: Water transport through olive cuticles and cuticle-inspired membranes measured by radiolabeled ³H₂O permeation tests.

a, b Schematics (not to scale) of the measurement configurations and box plots showing the outward and inward transport of ³H₂O through olive cuticles with and without waxes under varying relative humidity conditions at the receiver (RH_R = 2 or 100%) and membrane orientations. The geometry was varied so that a the inner cuticular side (outward transport) and b the outer cuticular side (inward transport) faced the donor (RH_D = 100%). Permeances were calculated assuming the inner cuticular side as flat (solid orange and blue symbols and boxes) or rough (open green and purple symbols and boxes). c, d Box plots of the permeability asymmetry factor PAF of c ~20 μm olive cuticles and of d ~33-μm-thick membranes of SBS or SBS/CNC containing 15 wt% CNCs determined by ³H₂O permeation experiments with the CNC-rich bottom side and the top side facing the donor (RH_D = 100%). In all box charts, whiskers extend to min and max values, box edges show 25–75 percentiles, center line represents median, and hollow square represents mean. The experiments were conducted at 25 °C with n = 8 (olive with waxes), n = 6 (olive without waxes), and n = 3 (SBS neat, SBS/CNC 15%) different membranes.