This study describes buckling instabilities mediated via surface roughness to generate hierarchical structures on a metal (aluminum)/polymer (polystyrene) laminated composite bilayer film on a rigid substrate. Buckling instability is a non-lithographic approach to generate microscale features in thin films. Metals can buckle over the surface due to compressive stress arising from differences in thermal expansion of the individual layers. The topographies of the buckles characterized by wavelength and amplitude can be manipulated by varying the thickness of the layers and the extent of thermal annealing time. Here, the pre-buckled surface on the laminated composite bilayer film formed via two–step molding resulted in hierarchical patterns via surface roughness-mediated buckling instability. The negative replica of the buckles was generated by poly(dimethyl siloxane) (PDMS) and the positive replica of the buckles was fabricated via molding using a PDMS negative replica onto the PS film. The metal layer was subsequently formed on the PS film and the laminated composite bilayer film enabled patterns with hierarchical topography following thermal treatment. The hierarchically structured surfaces exhibit moderately enhanced hydrophilicity and the elastomeric replica with hierarchical buckles showed stretchable hydrophobicity up to 120% stretching due to partial preservation of the pre-structured buckles on the surface.

这项研究描述了通过表面粗糙度介导的屈曲不稳定性，从而在刚性基材上的金属（铝）/聚合物（聚苯乙烯）层压复合双层薄膜上产生分层结构。屈曲不稳定性是一种非光刻方法，可以在薄膜中产生微观特征。金属可能会由于各个层的热膨胀差异而产生的压缩应力而弯曲到表面上。可以通过改变层的厚度和热退火时间的范围来控制以波长和幅度为特征的带扣的形貌。在此，通过两步成型在层压复合双层薄膜上的预屈曲表面通过表面粗糙度介导的屈曲不稳定性产生了分层图案。带扣的负复制品是由聚二甲基硅氧烷（PDMS）生成的，带扣的正复制品是通过将PDMS负复制品模制到PS膜上而制成的。随后在PS膜上形成金属层，并且在热处理之后，具有分层形貌的层压复合双层膜使能图案。分层结构的表面表现出适度增强的亲水性，而具有分层折痕的弹性体复制品由于表面上预结构化的折曲的部分保留而显示出高达120％拉伸的可拉伸疏水性。随后在PS膜上形成金属层，并且在热处理之后，具有分层形貌的层压复合双层膜使能图案。分层结构的表面表现出适度增强的亲水性，而具有分层折痕的弹性体复制品由于表面上预结构化的折曲的部分保留而显示出高达120％拉伸的可拉伸疏水性。随后在PS膜上形成金属层，并且在热处理之后，具有分层形貌的层压复合双层膜使能图案。分层结构的表面表现出适度增强的亲水性，并且具有分层的带扣的弹性体复制品由于表面上预结构的带扣的部分保留而显示出高达120％拉伸的可拉伸疏水性。