Eichler-Volf Anna, Xue Longjian, Kovalev Alexander, Gorb Elena V, Gorb Stanislav N, Steinhart Martin
Institut für Chemie neuer Materialien, Universität Osnabrück, Barbarastr. 7, Osnabrück 49069, Germany.
School of Power and Mechanical Engineering, Wuhan University; Donghu South Road 8, Wuhan 430072, China.
Materials (Basel). 2016 May 14;9(5):373. doi: 10.3390/ma9050373.
Bioinspired artificial surfaces with tailored adhesive properties have attracted significant interest. While fibrillar adhesive pads mimicking gecko feet are optimized for strong reversible adhesion, monolithic microsphere arrays mimicking the slippery zone of the pitchers of carnivorous plants of the genus Nepenthes show anti-adhesive properties even against tacky counterpart surfaces. In contrast to the influence of topography, the influence of relative humidity () on adhesion has been widely neglected. Some previous works deal with the influence of on the adhesive performance of fibrillar adhesive pads. Commonly, humidity-induced softening of the fibrils enhances adhesion. However, little is known on the influence of on solid anti-adhesive surfaces. We prepared polymeric nanoporous monolithic microsphere arrays (NMMAs) with microsphere diameters of a few 10 µm to test their anti-adhesive properties at s of 2% and 90%. Despite the presence of continuous nanopore systems through which the inner nanopore walls were accessible to humid air, the topography-induced anti-adhesive properties of NMMAs on tacky counterpart surfaces were retained even at = 90%. This -independent robustness of the anti-adhesive properties of NMMAs significantly contrasts the adhesion enhancement by humidity-induced softening on nanoporous fibrillar adhesive pads made of the same material.
具有定制粘附特性的仿生人工表面引起了广泛关注。虽然模仿壁虎脚的纤维状粘附垫针对强可逆粘附进行了优化，但模仿猪笼草属食肉植物捕虫笼光滑区域的整体微球阵列即使在粘性对应表面上也表现出抗粘附特性。与形貌的影响相反，相对湿度（）对粘附的影响一直被广泛忽视。一些先前的工作探讨了相对湿度对纤维状粘附垫粘附性能的影响。通常，湿度引起的纤维软化会增强粘附力。然而，关于相对湿度对固体抗粘附表面的影响知之甚少。我们制备了微球直径为几十微米的聚合物纳米多孔整体微球阵列（NMMAs），以测试它们在2%和90%相对湿度下的抗粘附性能。尽管存在连续的纳米孔系统，潮湿空气可进入内部纳米孔壁，但即使在相对湿度 = 90%时，NMMAs在粘性对应表面上由形貌引起的抗粘附性能仍然得以保留。NMMAs抗粘附性能的这种与相对湿度无关的稳健性与由相同材料制成的纳米多孔纤维状粘附垫上湿度引起的软化导致的粘附增强形成了显著对比。
