Division of Natural and Applied Sciences, Duke Kunshan University, Kunshan, Jiangsu 215316, China.
Environmental Research Center, Duke Kunshan University, Kunshan, Jiangsu 215316, China.
Langmuir. 2022 Jul 26;38(29):8890-8898. doi: 10.1021/acs.langmuir.2c01002. Epub 2022 Jul 13.
The anisotropic adhesion behavior of the gecko is closely related to their feet and is comprised of keratinous hairs, setae, where van der Waals forces permit attachment and detachment during locomotion. Previous research either achieved only isotropic adhesion behaviors or involved the complicated photolithography method. Here, we reported a simple way to achieve the anisotropic adhesion behaviors of gecko-inspired adhesives, consisting of micropillars with asymmetrically tilted orientation via the 3D printing technique. The adhesive forces of structured polymer pillars achieved 4-fold stronger, compared to controls with the plain surface. The anisotropic adhesion behavior is presented on the patterned surface and is two times stronger along the gripping direction compared to the releasing direction on the adhesives, which is attributed to the asymmetric stress distributions at the edges, as well as the stresses resulting from the moment with the sheared top. The finite element analysis is applied to demonstrate the stress distributions and displacement variations. This work provides the insight into the design and fabrication of gecko-inspired adhesives with anisotropic adhesion behaviors in practical applications.
壁虎的各向异性粘附行为与其足部密切相关，它由角蛋白毛、刚毛组成，范德华力允许在运动过程中附着和脱离。以前的研究要么只实现了各向同性的粘附行为，要么涉及复杂的光刻方法。在这里，我们报告了一种简单的方法来实现基于壁虎的仿生粘合剂的各向异性粘附行为，该方法通过 3D 打印技术在具有不对称倾斜取向的微柱上实现。与具有平面表面的对照物相比，结构化聚合物支柱的粘附力强了 4 倍。各向异性粘附行为出现在图案化表面上，与释放方向相比，在粘附剂上沿握持方向的粘附力强两倍，这归因于边缘处的不对称应力分布，以及由于剪切顶部产生的力矩引起的应力。有限元分析用于演示应力分布和位移变化。这项工作为在实际应用中设计和制造具有各向异性粘附行为的基于壁虎的仿生粘合剂提供了深入的了解。
