Knapp André, Nebel Lisa Julia, Nitschke Mirko, Sander Oliver, Fery Andreas
Institute of Physical Chemistry and Polymer Physics, Leibniz Institute of Polymer Research Dresden e. V., Hohe Str. 6, 01069 Dresden, Germany.
Institute for Numerical Mathematics, Technical University Dresden, Zellescher Weg 12-14, 01069 Dresden, Germany.
Soft Matter. 2021 Jun 2;17(21):5384-5392. doi: 10.1039/d0sm02231d.
We demonstrate a novel approach for controlling the line defect formation in microscopic wrinkling structures by patterned plasma treatment of elastomeric surfaces. Wrinkles were formed on polydimethylsiloxane (PDMS) surfaces exposed to low-pressure plasma under uniaxial stretching and subsequent relaxation. The wrinkling wavelength λ can be regulated via the treatment time and choice of plasma process gases (H2, N2). Sequential masking allows for changing these parameters on micron-scale dimensions. Thus, abrupt changes of the wrinkling wavelength become feasible and result in line defects located at the boundary zone between areas of different wavelengths. Wavelengths, morphology, and mechanical properties of the respective areas are investigated by Atomic Force Microscopy and agree quantitatively with predictions of analytical models for wrinkle formation. Notably, the approach allows for the first time the realization of a dramatic wavelength change up to a factor of 7 to control the location of the branching zone. This allows structures with a fixed but also with a strictly alternating branching behavior. The morphology inside the branching zone is compared with finite element methods and shows semi-quantitative agreement. Thus our finding opens new perspectives for "programming" hierarchical wrinkling patterns with potential applications in optics, tribology, and biomimetic structuring of surfaces.
我们展示了一种通过对弹性体表面进行图案化等离子体处理来控制微观皱纹结构中线缺陷形成的新方法。在单轴拉伸和随后的松弛过程中，对暴露于低压等离子体的聚二甲基硅氧烷（PDMS）表面形成皱纹。皱纹波长λ可以通过处理时间和等离子体处理气体（H2、N2）的选择来调节。顺序掩膜允许在微米尺度上改变这些参数。因此，皱纹波长的突然变化变得可行，并导致位于不同波长区域边界处的线缺陷。通过原子力显微镜研究了各个区域的波长、形态和力学性能，其结果与皱纹形成分析模型的预测在数量上一致。值得注意的是，该方法首次实现了高达7倍的显著波长变化，以控制分支区域的位置。这使得结构具有固定的以及严格交替的分支行为。将分支区域内的形态与有限元方法进行比较，显示出半定量的一致性。因此，我们的发现为“编程”分层皱纹图案开辟了新的前景，这些图案在光学、摩擦学和表面仿生结构化方面具有潜在应用。
