Fabrication of large‐area linear and nonlinear surface ripple structures on polystyrene films

Ripple structures have been used in electronics, optics, magnetics, chemistry, and structural coloration. Commonly used methods for manufacturing large‐area polymeric thin films with ripple structures include mechanical buckling, fracture‐induced structures (FISs), and laser induced periodic surface structures (LIPSS). In this study, we further proposed two FIS methods to fabricate easily and quickly large area self‐generated nonlinear and linear micro‐ripple structures. The initially featureless polystyrene film was effectively bonded between two rigid JIS SKD 61 (SKD61) steel cylinders and two soft PET films and then peeled off, the latter was cryogenically treated in liquid nitrogen before peeling off, the polystyrene film fractured into two complementary sets of nonlinear and linear micro‐ripple structures of the same period. The SKD61/ polystyrene (PS)/SKD61 sandwiched film used a slower peeling velocity and a thinner polystyrene film, which could fabricate a more complete and shorter period nonlinear wave structure. As the PET/PS/PET sandwiched film was cryogenically processed, it could produce a steeper waveform and flat valley linear ripple structures without cracks and ripple dislocations, with a period about 37 μm and an area about 300 cm2. A linear micro‐ripple structure may be produced by first sandwiching a featureless polystyrene film between two soft PET films with good interfacial bonding. After the sandwiched film undergoes a cryogenic treatment in liquid nitrogen then a slower peeling velocity may be applied to produce a ripple with a steeper waveform and flatter grain‐like valleys, but there are no cracks and ripple dislocations. The methods can be used to manufacture large‐area micro structural components and devices.