Secondary structure and surface properties of the SF film and composite SF/GO films. (A–C) Curve fitting result of FTIR spectrum in the amide I spectra of SF (A), SG2 (B), and SG10 (C). (D) Percentage of beta-sheets, turns, alpha-helix, and random coils determined by amide I deconvolution of SF/GO films. (E) Contact angle measurements of SF film (a), SG2 film (b), and SG10 film (c). *P < 0.05, **P < 0.01, data are presented as mean ± SD, n = 3.