Enhanced Stretchability of Wavy‐Structured Thermally Grown Silicon Dioxide Films for Stretchable Encapsulation

Aligned wavy‐structured thermally grown silicon dioxide films are fabricated for stretchable encapsulation films. Uniaxial stretchability is investigated with micromechanics modeling, which can elucidate the stretchability arising from the wavy structure and the properties of the materials. The wavy‐structured films with optimum combinations of film thickness and wavy structure show 20.1% of uniaxial stretchability and 1.11 × 10−6 g m−2 day−1 of water vapor transmission rate (WVTR), simultaneously. It shows highly reliable barrier properties even after 1000 stretching cycles at 90% of their stretchability. Thermally grown SiO2 is fabricated through substrate texturing to realize high stretchability. The mechanical behavior of the wavy‐structured film is investigated, and a stretchability estimation equation is derived with a stress model of the wavy‐structured film during stretching deformation to analyze the relationship between stretchability and structures, and to design the optimal structure for highly stretchable and impermeable materials.