As a first step in the synthetic Gecko fiber fabrication it is necessary to develop techniques to create the micro and nano-fibers independently. Once this is accomplished, it is possible to begin integrating the two types of fibers into a single process. The final structure will be a micro-fiber with nano-fibers branching out the end of the micro-fiber.
The first fabrication method utilizes commercially available components while the second method utilizes MEMS techniques to fabricate custom master molds. In both methods, liquid polymer is poured over the molds and cured. The cured molded polymer emerged in the desired physical form. It is possible to approximate the physical characteristics of the beta keratin by selecting the proper polymer.
Results from this method are promising. 200nm diameter high aspect ratio fibers have been produced, which are similar to the distal hairs found in Geckos robot. It is clear that there is bunching or matting occurring between the fibers increases, the inter fiber adhesion force surpasses the spring force of the fiber to remain upright and the fibers begin to bunch. This problem is caused by the high aspect ratio of the commercially available nanopore membrane as well as the high density. To avoid this bunching issue, a second method of fabrication was developed in which the density, diameter and length could be independently controlled. This method entails patterning a silicon wafer through photolithography and using a deep reactive ion etch to create a negative mold for the fibers.
No comments:
Post a Comment