Abstract: The surface wetting properties of paper-process reconstituted tobacco and natural tobacco leaf under different relative humidity were investigated in present study. The advancing contact angle was measured by Dynamic Contact Angle Analyzer (DCA). Scanning Electron Microscope (SEM) and Atomic Force Microscope (AFM) were also utilized to compare the surface morphology. The results showed that whether the water or essence was used as the liquid medium, the advancing contact angle of natural tobacco leaf was greater than 90°. It exhibited a hydrophobic property. While the advancing contact angle of paper-process reconstituted tobacco is less than 90°, it presents its hydrophilic surface property. For tobacco leaf, a smoother surface, and denser leaf structure were observed as compared to paper-process reconstituted tobacco. Furthermore, the surface roughness of tobacco leaf is lower than paper-process reconstituted bobacco under different relative humidity(respectively 37.23 nm, 82.97 nm and 227.99 nm, 105.35 nm). The coarser surface and porous structures of paper-process reconstituted tobacco verified the finding of its dymatic contact angle.

Key words: paper-process reconstituted tobacco, tobacco leaf, wetting characteristic, dynamic contact angle