Micro-scale surface shape memory effects were investigated on multilayer films that were produced with alternating layers of PVAc and PU. Two different types of micro-scale patterns, including a sharp microprismatic pattern and a smooth microlens pattern, were embossed on the surface of the PVAc/PU multilayer films by a PDMS replica mold using the soft lithography method. The microprismatic pattern as a permanent surface structure on the intrinsically transparent multilayer films renders the films opaque and the microlens surface pattern endows the clear films with focusing properties. The micro-structured surface is programmed by compression and recovery to switch the corresponding optical property of the film. Based on this switchable optical property, the patterned PVAc/PU multilayer film can be employed as an anti-counterfeiting feature in packaging. In this paper, the shape memory effect of the multilayered film was found to be dependent on the composition of the PVAc relative to the PU layers. In addition, the shape memory effect of the layered PVAc/PU films was enhanced compared to the PVAc control film. The recovery mechanism of the shape memory films was interpreted using Burgers viscoelastic model. The effects of the compression pressure, recovery temperature and the geometry of the patterns on the micro-scale shape memory behavior of the PVAc/PU multilayer films were also investigated.

研究了用PVAc和PU交替层生产的多层膜的微观尺度表面形状记忆效应。使用软光刻法，通过PDMS复制模具在PVAc / PU多层膜的表面上压印两种不同类型的微尺度图案，包括清晰的微棱镜图案和平滑的微透镜图案。作为本质上透明的多层膜上的永久性表面结构的微棱镜图案使膜变得不透明，而微透镜表面图案赋予透明膜以聚焦特性。通过压缩和恢复对微结构化表面进行编程，以切换薄膜的相应光学特性。基于这种可切换的光学特性，图案化的PVAc / PU多层膜可以用作包装中的防伪特征。在本文中，发现多层膜的形状记忆效应取决于相对于PU层的PVAc的组成。另外，与PVAc控制膜相比，层状PVAc / PU膜的形状记忆效果得到增强。使用Burgers粘弹性模型解释了形状记忆膜的恢复机理。还研究了压缩压力，恢复温度和图案的几何形状对PVAc / PU多层膜的微观尺度形状记忆行为的影响。与PVAc控制膜相比，层状PVAc / PU膜的形状记忆效应得到增强。使用Burgers粘弹性模型解释了形状记忆膜的恢复机理。还研究了压缩压力，恢复温度和图案的几何形状对PVAc / PU多层膜的微观尺度形状记忆行为的影响。与PVAc控制膜相比，层状PVAc / PU膜的形状记忆效应得到增强。使用Burgers粘弹性模型解释了形状记忆膜的恢复机理。还研究了压缩压力，恢复温度和图案的几何形状对PVAc / PU多层膜的微观尺度形状记忆行为的影响。