Zhang Wang, Wang Hao, Wang Hongtao, Chan John You En, Liu Hailong, Zhang Biao, Zhang Yuan-Fang, Agarwal Komal, Yang Xiaolong, Ranganath Anupama Sargur, Low Hong Yee, Ge Qi, Yang Joel K W
Engineering Product Development, Singapore University of Technology and Design, Singapore, 487372, Singapore.
Nanofabrication Department, Institute of Materials Research and Engineering, Singapore, 138634, Singapore.
Nat Commun. 2021 Jan 4;12(1):112. doi: 10.1038/s41467-020-20300-2.
Four-dimensional (4D) printing of shape memory polymer (SMP) imparts time responsive properties to 3D structures. Here, we explore 4D printing of a SMP in the submicron length scale, extending its applications to nanophononics. We report a new SMP photoresist based on Vero Clear achieving print features at a resolution of ~300 nm half pitch using two-photon polymerization lithography (TPL). Prints consisting of grids with size-tunable multi-colours enabled the study of shape memory effects to achieve large visual shifts through nanoscale structure deformation. As the nanostructures are flattened, the colours and printed information become invisible. Remarkably, the shape memory effect recovers the original surface morphology of the nanostructures along with its structural colour within seconds of heating above its glass transition temperature. The high-resolution printing and excellent reversibility in both microtopography and optical properties promises a platform for temperature-sensitive labels, information hiding for anti-counterfeiting, and tunable photonic devices.
形状记忆聚合物（SMP）的四维（4D）打印赋予3D结构时间响应特性。在此，我们探索亚微米长度尺度下SMP的4D打印，将其应用扩展到纳米声学领域。我们报道了一种基于Vero Clear的新型SMP光刻胶，使用双光子聚合光刻（TPL）实现了约300 nm半间距分辨率的打印特征。由具有尺寸可调多颜色的网格组成的打印件使得能够通过纳米级结构变形研究形状记忆效应，以实现大的视觉变化。随着纳米结构变平，颜色和打印信息变得不可见。值得注意的是，在加热到高于其玻璃化转变温度的几秒钟内，形状记忆效应恢复了纳米结构的原始表面形态及其结构颜色。高分辨率打印以及微观形貌和光学特性方面的出色可逆性为温度敏感标签、防伪信息隐藏和可调谐光子器件提供了一个平台。
