From gecko body \”Arts\”: ultralyophobic, super adhesive adhered fibers, virtually any surface can be glued
As we all know, geckos, lizards, spiders and other reptiles can easily climb on a variety of surfaces. This is because of the numerous micro or nano fiber array on their pads, van der Waals forces, and capillary forces so that it may serve as a high-performance dry binder, can be stably attached to the various surfaces. For nearly two decades, scientists are inspired by reptiles, fiber adhesive has been extensively studied, the successful synthesis of the fiber can be firmly attached to the adhesive on a variety of surfaces. However, so far none has both high adhesion and strongly lyophobic fibrous adhesive, Many man-made fibers having high hydrophobic adhesive, when the liquid surface in contact with the low surface tension of the adhesive performance will be greatly reduced.
Recently, in Stuttgart, Germany Marx Planck Institute for Intelligent Systems Metin Sitti reported a species elastic biologically inspired fiber adhesive , combines a mushroom-shaped fibers strongly adherent and fiber tip biconcave angle geometry hydrophobic shape, [123 ] not only exhibits a low surface tension liquid repellent liquid superacid, while maintaining superior adhesive properties. The liquid repellency strong adhesive fibers can be effectively used in water, oil or other liquid surface ; In addition, the fiber adhesive is also highly deformability and stretchability, can withstand strong degree of physical effects, greatly expanded the scope of its practical application. Production
Adhesive elastic fibers Researchers based 3D rigid manufacturing technology of printing, the adhesive fibers obtained by a molding process twice, using PDMS as the elastomer, and the manufacturing method for a variety of elastomeric material. Production process shown in Figure 1, two-photon polymerization is first used on a glass substrate 3D printing fiber array; The monomer to crosslinker ratio 20: PDMS composition for cast and cured on the fiber array fluorosilane of; then molding the PDMS master article, and then a crosslinking agent and monomersRatio of 10: 1 for release of PDMS composition, a fiber adhesive having elasticity.
liquid repellency test
Researchers adhesive fibers characterized by the contact angle measurements lyophobic results As shown, the fibers of the adhesive even low surface tension liquids methanol, perfluorohexane also showed strong lyophobic 2;
subsequently, the researchers characterized the adhesion of the adhesive through the fiber tensile test. The results shown in Figure 5, even at low preload 2mN, and can withstand the tension of the fibers is also higher than the adhesive surface of the adhesive smooth control (broken line in FIG. 5b) is about five times! When the adhesive and the fibrous cap diameter exceeds 28 μm, adhered stress exceeds 100 kPa, which show that the superior adhesion of the adhesive fibers.