fig4

Figure 4. Flexible films with vertically uniaxial buckling structures. (A) Schematic of a PET film with an aperiodic buckling structure and attached electronic foil, along with a 3D digital optical microscope image. Reproduced with permission^[45]. Copyright 2015, Wiley-VCH; (B) Schematic of the buckling structure formed on a PI/AgNW composite electrode and the wrinkled surface morphology of the composite electrode. Reproduced with permission^[47]. Copyright 2019, Wiley-VCH; (C) Schematic of the buckling structured PS film on the PDMS, including a cross-sectional depiction of the interface layer between the PS and the PDMS. Reproduced with permission^[49]. Copyright 2024, Springer Nature; (D) Planar SEM image of a PI film replicated using a micro-wrinkle pattern mold, including surface morphology and cross-sectional SEM images of the wrinkles. Reproduced with permission^[51]. Copyright 2024, Elsevier; (E) SEM image of a periodic buckling pattern on a PET film created by a laser-programmable process. Reproduced with permission^[52]. Copyright 2016, Springer Nature; (F) SEM images of the isotropically buckled parylene film structure replicated using a micro-patterned silicon mold. Reproduced with permission^[53]. Copyright 2021, Wiley-VCH. PET: Polyethylene terephthalate; PI: polyimide; AgNW: Ag nanowire; PS: polystyrene; PDMS: polydimethylsiloxane; SEM: scanning electron microscope.