An Ultraviolet-Curable Mold for Sub-100-nm Lithography

Choi, Seungjin; Yoo, Pil J.; Baek, Seung Jae; Kim, Tae W.; Lee, Hong H.

doi:10.1021/ja048972k

Cited by 294 publications

(293 citation statements)

References 15 publications

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“…25 The second approach renders complete transfer of submicrometer features with sub-50 nm edge resolution using a chemical catalyst bound to a rigid polymeric stamp capable of supporting very accurate high-resolution patterns. 27,28 In this variation, a polyurethane-acrylate stamp bearing 2-aminomethyl piperidine was used to promote catalytic deprotection of an Fmoc-protected SAM. The technique achieves 100% cleavage of Fmoc-groups in regions of stamp-substrate contact and allows subsequent functionalization of printed surfaces.…”

mentioning

confidence: 99%

Inkless Microcontact Printing on SAMs of Boc- and TBS-Protected Thiols

2009

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We report a new inkless catalytic µCP technique that achieves accurate, fast, and complete pattern reproduction on SAMs of Boc-and TBS-protected thiols immobilized on gold using a polyurethane-acrylate stamp functionalized with covalently bound sulfonic acids. Pattern transfer is complete at room temperature just after one minute of contact and renders sub-200 nm size structures of chemically differentiated SAMs.KEYWORDS Microcontact printing, soft lithography, catalytic lithography M icrocontact printing (µCP) was first introduced by Whitesides and co-workers in 1993 as a new flexographic technique for patterning self-assembled monolayers (SAMs) on metal surfaces. 1-9 It represents the prototypical embodiment of a family of related patterning techniques, collectively termed soft lithography, that make use of conformal contact between a substrate and a flexible stamp as a means of pattern reproduction. 5,8,10 Since its inception, µCP has become a highly successful lowcost printing method that efficiently reproduces high-resolution patterns over large surface areas. During the past 20 years µCP has been successfully utilized to pattern small organic compounds, inorganic substances, biomolecules, and even living cells on a variety of hard materials. Recently, µCP has been used for the fabrication of organic thin film transistors, where it is utilized as an inkjet printing alternative to pattern conductive organic polymers on both hard and flexible substrates. [11][12][13] Although traditional µCP is capable of reproducing features with reasonably high spatial resolution, structures smaller than 300 nm significantly limit the number of possible ink-substrate systems and demand precise control over stamping time, the amount of ink applied, the printing force, and the shape and definition of the stamp pattern. 6,14 In routine applications, several shortcomings of traditional µCP, especially distortion and deformation of the elastomeric stamp, 15,16 and more importantly, spreading of molecular inks by both gas diffusion and diffusive wetting, 17 preclude accurate replication of submicrometer features. Several approaches to minimize ink spreading have recently been developed, through substitution of liquid inks by various solid analogues, such as polymers and metal thin films, [18][19][20][21][22] or by avoiding the use of chemical inks completely and utilizing instead a catalytic reaction between the elastomeric stamp and substrate. [23][24][25][26] The first example of catalytic microcontact printing was reported in 2003 by Reinhoudt et al., who used an oxidized PDMS stamp to deprotect TMS-and TBS-modified SAMs on gold. The method clearly demonstrated the ability of an acidic stamp to deprotect immobilized silyl ethers and reproduce micrometersize features with sub-100 nm edge resolution, although the approach achieved only partial cleavage and required a new stamp for each pattern transfer. 23 Recently, we reported two inkless µCP methods that employ catalysts bound to polymeric stamps to reproduce patterns...

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confidence: 99%

Inkless Microcontact Printing on SAMs of Boc- and TBS-Protected Thiols

2009

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“…The droplet then spread, forming a thin precursor layer. After droplet 45 spreading, we used a 75 ms UV exposure to generate maskdefined polymerized structures in the sandwiched precursor layer. Typically, photocrosslinked PEGDA structures between glass slides adhered to the glass surfaces.…”

Section: Oxygen Inhibited Radical Polymerization On Pfpe Surfacesmentioning

confidence: 99%

“…Also, the PU monomer was selected as an exemplary hydrophobic monomer among a wide range of water-10 insoluble monomers. This UV curable hydrophobic monomer has been used for the preparation of replica molds that have patterns with sub-100nm feature resolutions and low surface energy comparable to PDMS 45 . In addition, PU has provided biocompatibility for the construction of scaffolds in tissue 15 engineering 46,47 .…”

Section: Comparison With Pdms-based Flow Lithographymentioning

confidence: 99%

Stop flow lithography in perfluoropolyether (PFPE) microfluidic channels

2014

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5Stop Flow Lithography (SFL) is a microfluidic-based particle synthesis method for creating anisotropic multifunctional particles with applications that range from MEMs to biomedical engineering. Polydimethylsiloxane (PDMS) has been typically used to construct SFL devices as the material enables rapid prototyping of channels with complex geometries, optical transparency, and oxygen permeability. However, PDMS is not compatible with most organic solvents which limit the current range of materials 10 that can be synthesized with SFL. Here, we demonstrate that a fluorinated elastomer, called perfluoropolyether (PFPE), can be an alternative oxygen permeable elastomer for SFL microfluidic flow channels. We fabricate PFPE microfluidic devices with soft lithography and synthesize anisotropic multifunctional particles in the devices via the SFL process -this is the first demonstration of SFL with oxygen lubrication layers in a non-PDMS channel. We benchmark the SFL performance of the PFPE 15 devices by comparing them to PDMS devices. We synthesized particles in both PFPE and PDMS devices under the same SFL conditions and found the difference of particle dimensions was less than a micron. PFPE devices can greatly expand the range of precursor materials that can be processed in SFL because the fluorinated devices are chemically resistant to most organic solvents, an inaccessible class of reagents in PDMS-based devices due to swelling.

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“…Drops of a prepolymer solution of polyurethane acrylate (PUA) were dispensed onto this template, and the film was lightly pressed with a polyethylene terephthalate (PET) backplane sheet. Exposure to ultraviolet light cures the prepolymer 11 . The PET sheet removed from the template has an array of PUA prisms on its surface.…”

Section: Fabrication Of the Lucius Prism Array The Fabrication Of Thementioning

confidence: 99%

Arrays of Lucius microprisms for directional allocation of light and autostereoscopic three-dimensional displays

Yoon

Kang

et al. 2011

Nat Commun

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Directional and asymmetric properties are attractive features in nature that have proven useful for directional wetting, directional flow of liquids and artificial dry adhesion. Here we demonstrate that an optically asymmetric structure can be exploited to guide light with directionality. The Lucius prism array presented here has two distinct properties: the directional transmission of light and the disproportionation of light intensity. These allow the illumination of objects only in desired directions. set up as an array, the Lucius prism can function as an autostereoscopic three-dimensional display.

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An Ultraviolet-Curable Mold for Sub-100-nm Lithography

Cited by 294 publications

References 15 publications

Inkless Microcontact Printing on SAMs of Boc- and TBS-Protected Thiols

Inkless Microcontact Printing on SAMs of Boc- and TBS-Protected Thiols

Stop flow lithography in perfluoropolyether (PFPE) microfluidic channels

Arrays of Lucius microprisms for directional allocation of light and autostereoscopic three-dimensional displays

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