Xue Cheng, Zhang Yachao, Li Longfu, Hu Yanlei, Chen Chao, Song Yuegan, You Hongshu, Li Rui, Li Jiawen, Wu Dong, Chu Jiaru
CAS Key Laboratory of Mechanical Behavior and Design of Materials, Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes, Department of Precision Machinery and Precision Instrumentation, University of Science and Technology of China, Hefei, Anhui 230027, China.
ACS Appl Mater Interfaces. 2021 May 19;13(19):23210-23219. doi: 10.1021/acsami.1c04049. Epub 2021 May 7.
Spontaneous wrinkling of films with a thickness gradient offers a new opportunity for constructing various 3D hierarchical surface morphologies. Unfortunately, accurately and facilely controlling the gradient film thickness to yield multiscale and 3D hierarchical micro-/nanostructures is still difficult. Here, a rapid, facile, and highly controllable fabricating strategy for realizing 3D multiscale hierarchical micro-/nanofolds on a shape memory polymer (SMP) surface is reported. First, the nanoparticle film with gradient thickness is rapidly (100 ms to 4 s) and facilely obtained by laser intermittent ablation on the SMP, termed as laser ablation-induced gradient thickness film. Following one-time constrained heating, the 3D micropillars grow out of the substrate based on the "self-growing effect," and the nanoparticle gradient film on its top shrinks into multiscale micro-/nanofolds simultaneously. Significantly, the evolution process and the underlying mechanism of the 3D micro-/nanofolds are systematically investigated. Fundamental basis enables us to accurately regulate the gradient thickness of nanoparticle films and feature size of folds by varying laser scanning times and scanning path. Finally, desirable patterns on micro-/nanofolds can be readily realized by programmable laser cleaning technology, and the tunable adhesion of the water droplet on the multiscale structured surface is demonstrated, which is promising for microdroplet manipulation.
具有厚度梯度的薄膜自发褶皱为构建各种三维分级表面形态提供了新机会。不幸的是，精确且简便地控制梯度薄膜厚度以产生多尺度和三维分级微/纳米结构仍然很困难。在此，报道了一种在形状记忆聚合物（SMP）表面实现三维多尺度分级微/纳米褶皱的快速、简便且高度可控的制造策略。首先，通过在SMP上进行激光间歇烧蚀快速（100毫秒至4秒）且简便地获得具有梯度厚度的纳米颗粒薄膜，称为激光烧蚀诱导梯度厚度薄膜。经过一次约束加热，基于“自生长效应”，三维微柱从基底上生长出来，并且其顶部的纳米颗粒梯度薄膜同时收缩成多尺度微/纳米褶皱。值得注意的是，系统地研究了三维微/纳米褶皱的演变过程和潜在机制。基本原理使我们能够通过改变激光扫描次数和扫描路径来精确调节纳米颗粒薄膜的梯度厚度和褶皱的特征尺寸。最后，通过可编程激光清洗技术可以轻松实现微/纳米褶皱上所需的图案，并且展示了水滴在多尺度结构化表面上的可调附着力，这对于微滴操纵具有前景。
