*2.2. Lotus Leaves*

The fresh lotus leaves (*Nelumbo nucifera*) were collected in Autumn 2018 (September-October) and were kindly provided by the Jardim Botânico of Universidade de Coimbra. The hierarchical surface morphology of the lotus leaf was observed by Scanning Electron Microscopy (SEM, Hitachi, Chiyoda, Japan). For that, pieces of lotus leaves were fixed with 5% (*v*/*v*) glutaraldehyde at 4 ◦C for 12 h. After that, samples were washed once with phosphate buffer saline (PBS) and the dehydration was carried out in ethanol series for 1 h each (30, 50, 70, 80, 90% (*v*/*v*), and absolute) at room temperature [14,15]. The samples were then allowed to dry overnight in a desiccator. Finally, samples were coated with gold and analyzed by VP SEM Hitachi S-3400N (Hitachi, Chiyoda, Japan) using a voltage of 20.0 kV and 100.0 μA emission.

## *2.3. Negative Template Fabrication*

PDMS was used to produce the lotus leaf negative template. The lotus leaves were gently cut and glued to glass Petri dishes. Then, molten paraffin was placed on the edges of the Petri dishes to seal the samples and prevent the polymer from dripping. Initially, the mixture of PDMS and its catalyzer (10:1; *w*/*w*) were weighed and mixed by hand for 5 min in order to improve homogeneity. Then, this mixture was degassed under vacuum until visible air bubbles formed during the mixing procedure had disappeared (30 min) [16]. Finally, the mixture was cast on the previously prepared Petri dishes with the lotus leaves [17]. The Petri dishes were then placed into a ventilated oven for a curing time of 4 h at 60 ◦C and then were left for more 48 h at room temperature [16] (Figure 1a). The negative template produced was visualized by SEM. Small pieces of the negative template were directly mounted on stubs and then coated with gold and analyzed by VP SEM Hitachi S–3400N using a voltage of 20.0 kV and 100.0 μA emission.

#### *2.4. Preparation of Zein-Based Films*

The film-forming solution was prepared by dissolving zein powder in 80% (*v*/*v*) ethanol-water solution (10%; *w*/*v*) under magnetic stirring for 30 min at 80 ◦C and 250 rpm. Glycerol at 25% (g glycerol/g dry zein powder) was added to the solution as plasticizer agent and stirred for 8 min at 80 ◦C and 250 rpm [18]. Then, licorice EO at 30% (g EO/g dry zein powder) was incorporated and was stirred again (8 min, 80 ◦C, 250 rpm) [13,18]. Films were then obtained by casting. For this purpose, the film-forming solution was spread on polystyrene Petri dishes in which the lotus leaf negative template was mounted as described above (Figure 1a), allowing the obtention of zein-based films with similar hierarchical surface morphology to that of the lotus leaf (positive replica). Films were also obtained by spreading the film-forming solution on simple polystyrene Petri dishes. Finally, the Petri dishes were placed into a ventilated oven to dry the mixture (24 h, 40 ◦C). The positive replica films obtained were observed by SEM as described for the negative template.

## *2.5. Characterization of Films*

The control film (without EO) and the film with EO, both casted on simple polystyrene Petri dishes and on lotus negative template, were further characterized.
