Moon, Myoung-Woon Cha, Tae-Gon Lee, Kwang-Ryeol Vaziri, Ashkan Kim, Ho-Young 2024-01-20T19:00:44Z 2024-01-20T19:00:44Z 2021-09-04 2010-08 1744-683X https://pubs.kist.re.kr/handle/201004/131227 Asymmetric adhesion is used by many insects and gecko lizards, allowing them to move on nearly any surface - horizontal, tilted or vertical. The feet of many of these creatures is covered with intricate fibrillar structures that are responsible for their superb manoeuvring ability. Among these creatures, gecko lizards have one of the most efficient and interesting adhesion devices consisting of finely angled arrays of branched fibers (setae). Here, we developed a method to create tilted Janus (two-face) micropillars on the surface of an elastomeric polymer to mimic the geometry of a gecko's footpad. The method combines soft lithography to create straight micropillars and ion beam irradiation to tilt the straight micropillars in a controlled fashion. A set of experiments were performed to measure the adhesion and friction characteristics of the fabricated tilted micropillars. Our experiments showed that the friction force along the tilting direction is approximately three times higher than the friction force associated with the sliding against the tilting direction of tilted micropillars due to the difference in the contact area during sliding of a glass ball. English ROYAL SOC CHEMISTRY FOCUSED ION-BEAM MICROFIBER ARRAYS DRY ADHESIVE SURFACE FRICTION GECKOS ATTACHMENT DETACHMENT SUBSTRATE NANOHAIRS Tilted Janus polymer pillars Article 10.1039/c0sm00126k 1 SOFT MATTER, v.6, no.16, pp.3924 - 3929 SOFT MATTER 6 16 3924 3929 scie scopus 000280655100029 2-s2.0-77955373406 Chemistry, Physical Materials Science, Multidisciplinary Physics, Multidisciplinary Polymer Science Chemistry Materials Science Physics Polymer Science Article FOCUSED ION-BEAM MICROFIBER ARRAYS DRY ADHESIVE SURFACE FRICTION GECKOS ATTACHMENT DETACHMENT SUBSTRATE NANOHAIRS micropillar tilting ion beam PDMS friction tilted micropillar lithography polymer