Search results for "Soft lithography"

Fast and blister-free irradiation conditions for cross-linking of PMMA induced by 2MeV protons

2013

For soft lithography, the conventional negative tone resists, such as SU-8, that are used to create the mold have a number of drawbacks. PMMA, which is normally used as a positive tone resist, can be used as a negative resist by using high-fluence irradiation conditions. In this report, we outline optimization of the irradiation conditions for PMMA thin films using 2MeV H^+ ions to exploit their ability to work as a negative tone resist at ion fluences above 1.0x10^1^5ionscm^-^2. The main aim was to induce cross-linking while maintaining the exposed regions free of blisters and maintaining short irradiation times. We found that by using a two-step process with a low-flux irradiation, follow…

Oligothiophenes for Pattern Formation by Stamping

2003

Oligothiophene monomers with a fixed length varying from 3 to 5 thiophene rings were prepared by Stille coupling. They were functionalised with one or two methacrylate groups to allow polymerization and cross-linking. These monomers can be patterned with the help of soft silicon stamps (e.g., with the micro-injection moulding in capillaries process) on substrates like glass or flexible polymer foils. If a photoinitiator has been added, they can then be hardened by exposure to UV-light through the transparent stamp. Afterwards the stamp can be removed. This allows the preparation of several centimeters long oligothiophene lines of a width varying between 50 and 0.5 μm. These lines of semicon…

Large-scale Nanopatterning of Single Proteins used as Carriers of Magnetic Nanoparticles

2010

4 páginas, 4 figuras.

Visualization of Molecular Recognition Events on Microstructured Lipid-Membrane Compartments by In Situ Scanning Force Microscopy This work was suppo…

2002

Better Actuation Through Chemistry: Using Surface Coatings to Create Uniform Director Fields in Nematic Liquid Crystal Elastomers.

2016

Controlling the molecular alignment of liquid crystal monomers (LCMs) within nano- and microstructures is essential in manipulating the actuation behavior of nematic liquid crystal elastomers (NLCEs). Here, we study how to induce uniformly vertical alignment of nematic LCMs within a micropillar array to maximize the macroscopic shape change using surface chemistry. Landau-de Gennes numerical modeling suggests that it is difficult to perfectly align LCMs vertically in every pore within a poly(dimethylsiloxane) (PDMS) mold with porous channels during soft lithography. In an untreated PDMS mold that provides homeotropic anchoring of LCMs, a radially escaped configuration of LCMs is observed. V…

Inorganic Materials and Ionic Liquids: Large-scale Nanopatterning of Single Proteins used as Carriers of Magnetic Nanoparticles (Adv. Mater. 5/2010)

2010

Microstructuring of phospholipid bilayers on gold surfaces by micromolding in capillaries

2005

Microstructuring of lipid bilayers on gold surfaces was achieved by micromolding in capillaries employing chemically modified polydimethylsiloxane (PDMS). Microfluidic networks of PDMS were prepared by micromolding and functionalized with thiol end-groups using 3-mercaptopropyltrimethoxysilane. The PDMS stamps were firmly attached to the gold substrate via quasi-covalent linkage providing a tight seal, a prerequisite for establishing individual addressable capillaries. Bilayers composed of POPC/POPG were subsequently prepared on microstructured self assembly monolayers of 11-amino-1-undecanethiol via strong electrostatic interactions. This way it is possible to generate individually address…

Polyelectrolytes on block copolymer surfaces

2004

Soft lithography and properties of amphiphilic block copolymers are combined in a new technique for the generation of patterned substrates, which can be used in different ways as templates for further processing. In these processing steps the deposition of polyelectrolytes, metals and grafting from polymerizations are used for the construction of different structures.

Biosilica electrically-insulating layers by soft lithography-assisted biomineralisation with recombinant silicatein.

2011

Fabrication of a negative PMMA master mold for soft-lithography by MeV ion beam lithography

2012

Abstract In this study, poly(methyl methacrylate) (PMMA) was investigated as a negative resist by irradiation with a high-fluence 2 MeV proton beam. The beam from a 1.7 MV Tandetron accelerator at the Plasma and Beam Physics Research Facility (PBP) of Chiang Mai University is shaped by a pair of computer-controlled L-shaped apertures which are used to expose rectangular pattern elements with 1–1000 μm side length. Repeated exposure of rectangular pattern elements allows a complex pattern to be built up. After subsequent development, the negative PMMA microstructure was used as a master mold for casting poly(dimethylsiloxane) (PDMS) following a standard soft-lithography process. The PDMS chi…