图5b显示，经过20多次摩擦后，240目数的砂纸由于其粗糙度更高，对于

Figure 5b shows that after more than 20 rubs, the 240-mesh sandpaper wears more severely to cotton fabrics due to its higher roughness. The contact angle data obtained is also the lowest at the same number of times. The contact angle decreases after 20 wears. To 140°. However, the wear of 1200-mesh sandpaper on cotton fabrics is relatively small, and the contact angle can still reach 145° after 20 wears.

Figure 5b shows that after more than 20 frictions, 240 subjects of sandpaper due to its higher roughness, for cotton fabric wear is more serious, the resulting contact angle data is also the lowest number of times, 20 wear after the contact angle reduced to 140 degrees. The 1200-eye sandpaper on the cotton fabric wear is smaller, after 20 wear contact angle can still reach 145 degrees.

Figure 5B shows that after 20 times of friction, 240 mesh sandpaper has higher roughness and more serious wear on cotton fabric, and the contact angle data obtained is the lowest under the same number of times. After 20 times of wear, the contact angle is reduced to 140 °。 However, the wear of 1200 mesh sandpaper on cotton fabric is smaller, and the contact angle can still reach 145 after 20 times of wear °。<br>