Owusu-Nkwantabisah Silas, Gillmor Jeffrey
Non-volatile Memory Solutions Group, Intel Corporation, 1600 Rio Rancho Blvd. SE, Rio Rancho, New Mexico 87144, United States.
Technical Solutions Division, Eastman Kodak Company, 1999 Lake Avenue, Rochester, New York 14650, United States.
ACS Appl Mater Interfaces. 2020 Oct 7;12(40):45657-45664. doi: 10.1021/acsami.0c14943. Epub 2020 Sep 23.
Unique and random wrinkle features are desired for applications, especially in anticounterfeiting. Multifunctional wrinkled materials as well as simple wrinkling methods are desired for more applications. In this study, free-standing wrinkle-patterned porous polymer films were prepared using a modified supercritical CO foaming strategy. Spontaneous wrinkling was generated by applying moderate normal stress to the polymer films while foaming in situ. The wrinkle characteristics (wavelength and amplitude) were shown to be governed by the film thickness and the magnitude of the applied stress. Excessive (>5000 N) or no stress produced no obvious wrinkling or foaming whatsoever. Moreover, different morphologies of the wrinkles such as brain coral and herringbone patterns were achieved depending upon the shape of the mold used to apply the stress. Thus, the patterns show unique features for each batch process. Notwithstanding, geometric shape of the foamed wrinkle area is customizable. The reported wrinkling strategy offers the complementary advantage of patterning a foam in a polymer film and templating a PDMS stamp for different applications such as "mask-less" soft lithography, anticounterfeiting, pattern transfer, flexographic printing, and displays.
独特且随机的皱纹特征在各种应用中都很有需求，尤其是在防伪领域。多功能皱纹材料以及简单的起皱方法适用于更多应用。在本研究中，采用改进的超临界CO₂发泡策略制备了独立的皱纹图案化多孔聚合物薄膜。在原位发泡过程中，通过对聚合物薄膜施加适度的法向应力产生自发皱纹。皱纹特征（波长和幅度）显示受薄膜厚度和施加应力的大小控制。过大（>5000 N）或无应力都不会产生明显的起皱或发泡现象。此外，根据用于施加应力的模具形状，可以实现不同形态的皱纹，如脑珊瑚纹和人字形图案。因此，每个批次工艺的图案都具有独特特征。尽管如此，发泡皱纹区域的几何形状是可定制的。所报道的起皱策略具有在聚合物薄膜中对泡沫进行图案化以及为不同应用（如“无掩膜”软光刻、防伪、图案转移、柔性版印刷和显示器）制作PDMS印章模板的互补优势。
