Chemically Patterned Flat Stamps for Microcontact Printing

Abstract

Locally oxidized patterns on flat poly(dimethylsiloxane) stamps for microcontact printing were used as a platform for the transfer of a hydrophilic fluorescent ink to a glass substrate. The contrast was found to be limited. These locally oxidized patterns were conversely used as barriers for the transfer of hydrophobic n-octadecanethiol. In this case a good contrast was obtained, but the pattern was found to be susceptible to defects (cracks) in the barrier layer. Local stamp surface oxidation and subsequent modification with 1H,1H,2H,2H-perfluorodecyltrichlorosilane, for use as a barrier in the transfer of n-octadecanethiol, 16-mercaptohexadecanoic acid, and octanethiol, resulted in remarkably good contrast and stable patterns. The improved ink transfer control is ascribed to the reduction of undesired surface spreading and a superior mechanical stability of the stamp pattern. This new approach substantially expands the applicability of microcontact printing and provides a tool for the faithful reproduction of even extremely low filling ratio patterns.

High‐Resolution Contact Printing with Chemically Patterned Flat Stamps Fabricated by Nanoimprint Lithography

“…Recently, a new transport-barrier concept was introduced using chemical patterns on a flat stamp surface as the barriers to transfer ink molecules either from the chemically patterned areas [16] or from the areas in between. [17,18] In principle, using a chemically patterned flat stamp can solve many or all stamp-stability issues.…”

“…Functionalization by 1H,1H, 2H,2H-perfluorodecyl-trichlorosilane (PFDTS) rendered it possible to transfer regular thiol inks using such flat stamps. [18] However, the feature size is limited by the shadow mask used. The smallest commercially available shadow mask has 350 nm features.…”

Topographically Flat, Chemically Patterned PDMS Stamps Made by Dip‐Pen Nanolithography

“…The mechanically stable flat stamp is prepared without a photomask (since the structure may be directly written onto the surface by DPN), and the pattern drawn by DPN combined with subsequent chemical modification of the exposed areas of the stamp, allows one to create a surface with well-defined chemical regions that can be used to confine ink transport to sub-100 nm dimensions and prevent the lateral diffusion of the ink (Scheme 1). Others have used contact inking, [29,30] metal contact masks, [31,32] and template-mediated selfassembly approaches[33] to fabricate (sub)micron-sized chemical patterns on PDMS, but the approach described herein is remarkably simple and straightforward to implement and does not require complex and expensive photo-or e-beam lithography. More importantly, the high registration and resolution of DPN allow one to create stamps using this approach that ** C.A.M.…”

“…The PEG patterned PDMS is typically exposed to an O 2 plasma for 30 s followed by rinsing and ultrasonication (to remove the PEG), in order to prepare the areas not blocked with the PEG features for further chemical functionalization. For these experiments, either a perfluorinated silane was used to render those areas ambiphobic [32] or a PEG silane was used to make them resist the adsorption of biomolecules. [31] As an initial proof-of-concept, we prepared a flat stamp with a pattern consisting of 7×5 arrays of 1μm dots defined initially by the DPN-generated PEG features with the surrounding areas passivated with 1H,1H,2H,2H-perfluorooctadecyltrichlorosilane (PFODTS).…”

Multivalent self-assembly at interfaces : from fundamentals kinetic aspects to applications in nanofabrication

“…86 After the local modification of the stamp surface through a mask, the stamp was inked with thiols and the unmodified areas of the surface led to ink transfer (Figure 2.5). perfluorodecyltrichlorosilane-covered area acts as an ink barrier, while the non-covered PDMS transfers the thiol to the gold substrate.…”