Simulation of hydrophobic lotus leaves for preparing hydrophobic starch blending films based on starch-based graphite oxide carbon

Inspired by the hydrophobic mechanism of lotus leaf, hydrophobic starch blending films based on starch-based graphite oxide carbon(S-GOCs) was synthesized, while nano calcium carbonate (nano-CaCO3) and hydrophobic plasticizer (acetyl tributyl citrate, ATC) were also introduced for further improving its water resistance. The TEM, SEM, XRD, and FTIR characterizations were used to analyze the properties of S-GOCs. With increased addition of the S-GOCs, the water contact angle (θw) increased prominently (θw: from 35.5° to 91.5°), the moisture content (MC) and the water vapor permeability (WVP) of the starch blending films significantly decreased (MC: from 22.19% to 14.12%; WVP: from 3.86 to 3.27 g m m−2 s−1 Pa−1). The addition of the nano-CaCO3 and ATC further promoted its waterproof properties with the highest θw, the lowest MC, and WVP (θw = 112.2°, MC = 11.15%, WVP = 2.88 g m m−2 s−1 Pa−1). Although the S-GOCs resulted in a higher volume dissolution (the total soluble matter (TSM) increased from 26.26% to 32.13%), the incorporation of nano-CaCO3 and ATC could minimize the solubility of the films (TSM = 23.40%). Careful evaluation of tensile strength (TS) and elongation at break (E) of the films has concluded that the S-GOCs could make the films more flexible, and the extra addition of nano-CaCO3 and ATC have no adverse effect on this balance. Combined with the result of surface free energy and the analysis of AFM and FTIR, the hydrophobic mechanism of the starch blending films was illustrated, which was due to the synergistic effect of reducing surface free energy, improving surface roughness and structure water resistance. Finally, a simple application in the packing field was developed to envisage the prospect of starch-blending film.