Property of Silicone
The non-adhesive property of silicone rubber was a major limitation to our product design. With the goal of attaching setae tape—a nanomaterial created to imitate the microscopic hairs found on the tips of gecko feet—to the surface of the therapy band, we began experimenting with various attachment methods.
Unlike conventional adhesives, setae relies on Van der Waals forces for attachment, giving it a lot more versatility in terms of sticking to surfaces. Additionally, because we were specifically told by the company that the setae tape could hold on to silicon rubber, our ideal solution was to directly adhere setae to the band. Unfortunately, the results did not meet our expectations; the nanomaterial did not stick. In fact, none of the typical adhesives we used—super glue, epoxy, holt-melt adhesive (glue gun)—were able to successfully attach the tape to the silicone rubber surface. The super glue and hot-melt adhesive came right off the surface of the band when we applied them, and the epoxy was too weak to withstand the resistance of the therapy band when force was applied during testing. With none of the typical adhesives working, we resorted to two methods: 1) applying duct tape to the areas of the therapy band that will be attached to setae-tape and 2) sewing. Sticking the setae tape to duct tape worked well, with the exception that the duct tape semi-detaches itself from the silicone rubber when too much force is applied. When we tried sewing, parts of the yarn took up too much space to allow maximum adhering surface area.
It would be most ideal if we could coat the band with setae-like nanomaterials ourselves through laser lithography, laser etching which can create patterns mere nanometers in size to effectively cover a material’s surface in countless artificial setae, but we do not have access to this technology.
Cost
One of the biggest limitations for our design is the cost of the setae band. We purchased a four 4” by 4” reusable grip pads that cost a total of $28.12. Assuming a typical therapy band is 34 inches long, we would use up most of the 4” by 4” setae adhesive pads. With that said, a therapy band along with the setae-coating would cost $3.50+$28.12=$31.62. It would be more cost-effective if it is possible to mass produce therapy bands laser-lithographed with setae.