Nanoimprint Replication of Biomimetic, Multilevel Undercut Nanostructures (original) (raw)
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Nanoimprinting of Biomimetic Nanostructures
Nanomanufacturing
Biomimetic micro- and nano- structures have attracted considerable interest over the last decades for various applications ranging from optics to life sciences. The complex nature of the structures, however, presents significant challenges for fabrication and their application in real-life settings. Nanoimprint lithography could provide an interesting opportunity in this respect. This article seeks to provide an overview of what has already been achieved using nanoscale replication technologies in the field of biomimetics and will aim to highlight opportunities and challenges for nanoimprinting in this respect in order to inspire new research.
Coatings, 2020
Nanoimprinting is a well-established replication technology for optical elements, with the capability to replicate highly complex micro-and nanostructures. One of the main challenges, however, is the generation of the master structures necessary for stamp fabrication. We used UV-based Nanoimprint Lithography to prepare hierarchical master structures. To realize structures with two different length scales, conventional nanoimprinting of larger structures and conformal reversal nanoimprinting to print smaller structures on top of the larger structures was performed. Liquid transfer imprint lithography proved to be well suited for this purpose. We used the sample prepared in such a way as a master for further nanoimprinting, where the hierarchical structures can then be imprinted in one single nanoimprinting step. As an example, we presented a diffusor structure with a diffraction-grating structure on top.
Bilayer, nanoimprint lithography
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2000
Nanoimprint lithography has been shown to be a viable means of patterning polymer films in the sub-100 nm range. In this work, we demonstrate the use of a bilayer resist to facilitate the metal liftoff step in imprinter fabrication. The bilayer resist technology exhibits more uniform patterns and fewer missing features than similar metal nanoparticle arrays fabricated with single layer resist. The bilayer resist relies upon the differential solubility between poly͑methyl methacrylate͒ and poly͑methyl methacrylate methacrylic acid copolymer͒. Evidence is presented that shows the technique has a resolution of better than 10 nm.
Reverse Nanoimprint Lithography for Fabrication of Nanostructures
Nanoscience and Nanotechnology Letters, 2012
We investigate the applicability of reverse nanoimprint lithography (RNIL) to fabricate nanostructures. In this method, a thermal ultra-violet (UV) resist is first spin-coated onto a daughter mold directly and then the UV resist is transferred onto the desired surface by a UV-imprinting process at a very low temperature and low pressure. Discrete-track recording media at 50-nm track pitch were fabricated. The images from the scanning electron microscope showed that RNIL is capable of fabricating uniform patterns of nano-scale structures. Several advantages of RNIL over the existing methods are described, including the ease of using low molding pressure and temperature, the speed of imprinting, and the thinner residual layer.
Biomimetic, hierarchical structures on polymer surfaces by sequential imprinting
Applied Surface Science, 2008
Thermal nanoimprint lithography (NIL) is based on the thermo-mechanical deformation of a polymer film above the glass transition temperature (T g ) and at an applied pressure. Sequential imprinting extends the process of thermal NIL to create hierarchical structures by carrying out secondary and tertiary imprintings at temperatures below the T g of a polymer. In this work, we demonstrate the use of sequential imprinting technique to fabricate two-and three-level hierarchical structures on polystyrene (PS) and poly(methyl methacrylate) (PMMA) films over a temperature range of 70-130 8C, with the aim to mimic the hierarchical structures found in biological systems. By mimicking the hierarchical structure in a plant leaf, the water contact angle of PS film was increased from 958 to 1288, while the water contact angle of PMMA film was increased from 718 to 1048, without any chemical treatment.
Polymer Imprint Lithography with Molecular-Scale Resolution
Nano Letters, 2004
We show that small diameter, single-walled carbon nanotubes can serve as templates for performing polymer imprint lithography with feature sizes as small as 2 nm − comparable to the size of an individual molecule. The angstrom level uniformity in the critical dimensions of the features provided by this unusual type of template provides a unique ability to investigate systematically the resolution of imprint lithography at this molecular scale. Collective results of experiments with several polymer formulations for the molds and the molded materials suggest that the density of cross-links is an important molecular parameter that influences the ultimate resolution in this process. Optimized materials enable reliable, repetitive patterning in this single nanometer range.
Recent Advances in Nano Patterning and Nano Imprint Lithography for Biological Applications
Procedia Engineering, 2014
Nano patterning and Nanoimprint lithography [NIL] has advanced to great heights in recent years. Customizing the surface at micro and nano scale is of great demand. It facilitates the handling and working at micro and nano scale level. Its applications towards medical field are growing day by day. Precise surface patterning with nanometer resolution has great potential in many medical and biological applications. It also provides a platform for fundamental studies of molecular and cell biology. This review article comprises of current trends and future scope of nano patterning and NIL. In this article we particularly focus on biological applications.
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2009
The organic-inorganic hybrid polymer Ormostamp was successfully used for the fabrication of inexpensive, transparent working stamps to be used in nanoimprint lithography. The stamps were produced from different masters by casting and UV exposure of a viscous precursor. The cured hybrid stamp with the replicated surface relief was imprinted into several thermoplastic materials with up to 180°C imprint temperature. In this article the authors show the effect of the imprint temperature on the structural fidelity. By using combined thermal and UV-nanoimprint lithography at 110°C imprint temperature, a resolution down to 35 nm is demonstrated. They also investigated deterioration effects due to plasma treatment to simulate the effect of multiple recoating steps.
Chemical patterning of sub-50-nm half pitches via nanoimprint lithography
Microelectronic Engineering, 2005
We report on a fabrication method of achieving local chemical modification of a surface at the sub-50-nm scale by a process sequence of nanoimprint lithography, gas phase surface modification and lift-off. This was combined with a new stamp fabrication via extreme ultraviolet interference lithography to produce extremely small patterns of high density and large area. In this method, we have demonstrated chemical patterns of a fluorinated silane on an unprecedented feature size of as small as 25-nm half pitch. However, chemical contrast of high quality needed for biological and sensing applications was still difficult to achieve due to the contamination on the background surface areas, which is associated with the lift-off process. This will be discussed with results obtained by subsequently immobilizing a fluorescence labeled protein on the chemical patterns using different lift-off conditions and process sequences.