Biomimic Plant Cuticle from Hyperbranched Poly(ricinoleic acid) and Cellulose Film

Plant cuticle is an ideal biobased packaging material with well-balanced performance. However, it could not be extracted from plants for practical applications. In this work, we successfully fabricated a biomimic plant cuticle from hyperbranched poly­(ricinoleic acid) (HBPRA, biobased content > 96%) and cellulose film through UV-initiated thio-ene click reaction. This biomimic cuticle possessed excellent transparency (transmittance ≈ 90% in the visible light range). The SEM observation showed that the biomimic cuticle was composed of two layers, which were perfectly attached. The properties of two surfaces of biomimic cuticle displayed significant differences. Cellulose side was hydrophilic with contact angle (CA) around 44° and pencil hardness > 6H. On the contrary, the HBPRA side was hydrophobic with CA about 91° and pencil hardness ≈ B. With respect to the slippery cellulose side, HBPRA side could attach to various substrates under gentle force. In addition, the tensile test showed good mechanical properties. The elongation at break and maximum stress of biomimic cuticle were 44% and 29 MPa, respectively. The above results suggest that the biomimic cuticle may have potential applications for packaging and displaying materials.