Atmospheric pressure argon plasma: an effective method to improve the hydrophilicity of the cellulose in paper

Due to the surface hydrophobicity, the absorbing effect of the tobacco extract droplets on the reconstituted tobacco paper is unsatisfactory. Therefore, the surface property regulation of the tobacco paper has gained increasing attention. This work reports a novel argon (Ar) plasma treatment technique for improving the surface hydrophilicity and bacteriostatic effect of the paper. Firstly, Ar plasma was selected as the treatment gas and its improving effect was demonstrated through studying the contact angle changes of water droplet on the A4 paper. Then, the capillary fibers on the paper were bombarded by Ar plasma jet. The extract droplet contact angle on the reconstituted tobacco paper-15 s surface is only 14.6° within 1 s. In comparison to the pristine paper (5.9°/s), the absorption dynamic of the droplet increased to as high as 62.5°/s, which indicated the hydrophilicity was greatly improved by the Ar plasma method. The mechanism for improving the surface hydrophilicity of the cellulose in the tobacco paper also contributed to the generation of holes by Ar plasma jet, which increased the surface permeability of cellulose. At last, Ar plasma treatment showed excellent bacteriostatic effect, which could effectively inhibit the propagation and growth of fungi , Escherichia coli , and Staphylococcus aureus on the tobacco paper.