Grain Boundaries of Self-Assembled Porous Polymer Films for Unclonable Anti-Counterfeiting

Grain boundaries widely exist in 2-D materials, and they are often considered as defects harming the physicochemical properties of materials. Here, we report unclonable anti-counterfeiting films based on the grain boundaries of patterned porous structures. The porous films are prepared from hydroxyl-end-functionalized polystyrene (OH-PS), polystyrene-block-poly(N,N-dimethylaminoethly methacrylate) (PS-b-PDMAEMA), and cyclic polystyrene (c-PS) via a typical breath figure process, during which the evaporation of solvents provides enough instability and promises the uniqueness of surface grain boundaries. The anti-counterfeiting tags are convenient to be authenticated by portable devices. The self-assembly nature of the arrays endows the films with an extremely high encoding capacity. Moreover, the present anti-counterfeiting films are configurable, transparent, flexible, and aesthetically appealing to adapt to various applications. This work demonstrates highly secure unclonable anti-counterfeiting films and provides new understandings to grain boundaries of 2-D materials.