The obviously reduced air permeability was probably due to the enhanced interaction between the cellulose fibers and GOnanosheets. GO nanosheets with abundant oxygen groups areinclined to show uniform dispersion and ordered alignment in poly-mer matrices by van der Waals interactions and hydrogen bondsbetween GO nanosheets and polymer chains (Huang et al., 2014;Pan et al., 2011; Xu et al., 2009; Yang et al., 2010), which wouldendow the composite film/fiber low gas permeability. Moreover,the finished paper would become smoother and denser (Fig. 2d)with increased GO content, which is also in favor of obtainingdecreased gas permeability. This could be proved by the reducedpaper thickness with higher GO content. As shown in Fig. 4, whenthe GO content increases, the thickness of the GO/cellulose papershows a similar decreasing trend with the gas permeability, sug-gesting the paper became more dense and compact.