Multiscale patterning of a metallic glass using sacrificial imprint lithography

Abstract

Bulk metallic glasses (BMGs) have been developed as a means to achieve durable multiscale, nanotextured surfaces with desirable properties dictated by topography for a multitude of applications. One barrier to this achievement is the lack of a bridging technique between macroscale thermoplastic forming and nanoimprint lithography, which arises from the difficulty and cost of generating controlled nanostructures on complex geometries using conventional top-down approaches. This difficulty is compounded by the necessary destruction of any resulting reentrant structures during rigid demolding. We have developed a generalized method to overcome this limitation by sacrificial template imprinting using zinc oxide (ZnO) nanostructures. It is established that such structures can be grown inexpensively and quickly with tunable morphologies on a wide variety of substrates out of solution, which we exploit to generate the nanoscale portion of the multiscale pattern through this bottom-up approach. In this way, we achieve metallic structures that simultaneously demonstrate features from the macroscale down to the nanoscale, requiring only the top-down fabrication of macro/microstructured molds. Upon detachment of the formed part from the multiscale molds, the ZnO remains embedded in the surface and can be removed by etching in mild conditions to both regenerate the mold and render the surface of the BMGs nanoporous. The ability to pattern metallic surfaces in a single step on length scales from centimeters down to nanometers is a critical step toward fabricating devices with complex shapes that rely on multiscale topography for their intended functions, such as biomedical and electrochemical applications.

Recent Advances in Metallic Glass Nanostructures: Synthesis Strategies and Electrocatalytic Applications

“…Nanomolds can be made out of anodic aluminum oxide (AAO), stainless steel, or even MGs. [12,47] Traditional TPF suffers from the unworkable flow resistance due to friction and nonwetting conditions at the template interface. [35] 3D-Ns are part of a larger group of electrodes referred to as one-body or binder-free electrodes (see Section 3.1).…”

Fabrication of arbitrary three-dimensional suspended hollow microstructures in transparent fused silica glass

“…Sacrificial template techniques have been used in combination with metallic glasses and bioglasses. However, the structures produced are restricted to open structures with lamellae or fibrous/porous surface structures [41,42]. By combining room temperature glass structuring and sacrificial template replication, it is possible, for the very first time, to generate nearly arbitrarily-shaped freeform three-dimensional channels and hollow structures in fused silica glass.…”

Self-Limiting Electrospray Deposition on Polymer Templates

“…Higuchi et al demonstrated the focusing effects of different designs of nonconductive stencil masks to change the size of nanoparticle deposits 19 . Osuji et al demonstrated that inverse masks of a grounded grid under a glass slide could lead to patterned deposits of polymer films 18 . More recently, Zhu and Chiarot demonstrated that the charging effects of ESD with near-field photoresist templates could result in focusing of towers of particles that greatly exceed the thickness of the mask 20 .…”