The structure and properties of polymer film are greatly affected by the patterns on its surface arising from solution convection. Therefore, it is necessary to explore more detail mechanism of pattern formation. Herein, we have successfully designed variable patterns on the surface of cellulose films via roller coating method. The cellulose with three degrees of polymerization was used as raw material, and a solution of N,N-dimethyl-acetamide/lithium chloride (DMAc-LiCl) was selected as the solvent system. The pattern variations were controlled by the solution viscosity, which was affected by the degree of polymerization of cellulose, concentration and temperature of solution. The formation process of the pattern on cellulose film was in situ tracked by video recording with the help of carbon black tracker. It was found that the solution moved from the edge of the cell pattern to the center at a relatively lower viscosity (η < 8.06 Pa s), and finally formed a polygon pattern with the convex center. With the increasing of the solution viscosity (η ≥ 8.06 Pa s), the direction of its convection was completely opposite and a circular or circular-like combination pattern with concave center appeared on the surface of the cellulose film. The higher the viscosity, the larger the concave area. Moreover, the film with polygon pattern demonstrated excellent mechanical properties, and also exhibited a potential anti-counterfeiting value. These results could provide guidance in perfecting the theory of polymer fluid, and regulating the structure and properties of polymer products.

溶液对流引起的聚合物膜的结构和性能受其表面图案的影响很大。因此，有必要探索更详细的图案形成机理。在这里，我们已经成功地通过辊涂法在纤维素膜的表面上设计了可变图案。使用三聚合度的纤维素作为原料，并选择N，N-二甲基乙酰胺/氯化锂（DMAc-LiCl）溶液作为溶剂体系。图案变化由溶液粘度控制，溶液粘度受纤维素的聚合度，溶液浓度和温度影响。借助于炭黑跟踪器，通过视频记录就地跟踪了纤维素膜上图案的形成过程。η  <8.06 Pa s），并最终形成具有凸中心的多边形图案。与溶液粘度（的增加η  ≥8.06帕或多个），其对流的方向是完全相反的和圆形或圆形状组合图案与出现在纤维素薄膜表面上的凹中心。粘度越高，凹面面积越大。此外，具有多边形图案的膜表现出优异的机械性能，并且还显示出潜在的防伪价值。这些结果可为完善聚合物流体理论，调节聚合物产物的结构和性能提供指导。