Abstract
The fracture-induced structure (FIS) can be formed by separating the sandwich structure specimen. The film was fractured into two complementary set of nonsymmetrical cracked ripples on substrates. In experiment I, we used the tension-splitting and peeling–splitting method to induced periodic ripples on low molecular weight polystyrene (PS) films. Then we investigated the effect of UV (ultraviolet) irradiation on the surface modulation of FIS for PS films. Next, we used high molecular weight PS as the material to discuss the effect of the different molecular weight on surface gratings by peeling–splitting method in experiment II. In order to remove impurities and additives from high molecular weight PS pellets, we used fractional precipitation method and observed the difference in FIS without and with fractional precipitation. Finally, we used low molecular weight PS and photoresist to form the bilayered film sandwiched by two silicon substrates in experiment III. After separating by peeling–splitting, we investigated the difference between monolayer and bilayer situation for fracture-induced structure. The spatial wavelength of the surface structures is a linear function of the film thickness which is independent of the splitting approaches. For both two splitting processes, the ratio of the spatial wavelength to the film thickness decreased with the increase of irradiation dose. Besides, the different kinds of polymers and molecular weight also have the effect on cracked ripples.