Presentation Title

Synthesis of Gecko Inspired Dry Adhesives using Microsphere Lithography

Faculty Mentor

Jonathan B Puthoff

Start Date

18-11-2017 9:45 AM

End Date

18-11-2017 10:00 AM

Location

9-247

Session

Engineering/CS 3

Type of Presentation

Oral Talk

Subject Area

engineering_computer_science

Abstract

Gecko-like synthetic adhesives (GSAs) are dry adhesives that replicate the function of gecko toepads through their microscopic fibrillar structure. To produce GSA molds, we fabricated Si templates using microsphere lithography. We formed a monolayer of polystyrene microspheres using colloidal self-assembly, then transferred this mask to a Si wafer. Next, we sputtered Au onto the mask and substrate and removed the microspheres using ultrasonication. The resulting Au-patterned Si wafer was exposed to a chemical etch to remove the uncoated material, which formed deep pits in the Si surface. This surface structure forms a template for the fabrication of soft polymer molds that can be used to fabricate GSAs. In order to make this template reusable, a mono-molecular layer of alkoxysilane was deposited on the Si wafer through vapor deposition.

Summary of research results to be presented

Through microsphere lithography, templates for the dry adhesives were reliably manufactured. Under a scanning electron microscope, these templates exhibited the regularly spaced pattern which would result in the fibrillar structures for the dry adhesives. The resulting silicon molds were also silanized, which altered their hydrophobicity such that the dry polymer adhesives produced from the mold releases easily. The silanized silicon templates may thus be used again in production, rather than consumed in the process.

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Nov 18th, 9:45 AM Nov 18th, 10:00 AM

Synthesis of Gecko Inspired Dry Adhesives using Microsphere Lithography

9-247

Gecko-like synthetic adhesives (GSAs) are dry adhesives that replicate the function of gecko toepads through their microscopic fibrillar structure. To produce GSA molds, we fabricated Si templates using microsphere lithography. We formed a monolayer of polystyrene microspheres using colloidal self-assembly, then transferred this mask to a Si wafer. Next, we sputtered Au onto the mask and substrate and removed the microspheres using ultrasonication. The resulting Au-patterned Si wafer was exposed to a chemical etch to remove the uncoated material, which formed deep pits in the Si surface. This surface structure forms a template for the fabrication of soft polymer molds that can be used to fabricate GSAs. In order to make this template reusable, a mono-molecular layer of alkoxysilane was deposited on the Si wafer through vapor deposition.