球面上皱褶花样的演化

文章从理论和实验两方面研究了通过控制柔性衬底的曲率来调控球面上应力诱导之皱褶花样的可行性。研究以Ag内核/SiO₂壳层微结构为对象。结果表明，当球形衬底的曲率较小且应力刚超过临界值时，皱褶花样为三角铺排的凹痕结构；而当应力进一步增大和 : 或衬底的半径增大时，则出现迷宫形的花样。皱褶的周期长度和临界屈曲应力都随衬底半径的增大而增大。此方向上的研究对于理解大自然中许多花样（比如花叶序与皱纹）的产生和演化具有重要的意义。

Feasibility of manipulating the thin film buckling patterns is investigated by changing the substrate curvature and the stress developed upon cooling. The numerical and experimental studies are based on the spherical SiO2 film/Ag substrate system. It is found that for a substrate with a relatively large curvature, the triangularly distributed dent-like buckling pattern forms when the nominal stress is just above a critical value. With increasing film stress and/or substrate radius, the labyrinth-like buckling patterns take over. Bothe the buckling wavelength and the critical buckling stress become larger with increasing substrate radius. Researches along this line are helpful to the understanding of the formation and evolution of many natural patterns including the phyllotactic arrangements and wrinkles.