Patterned self-assembled monolayers of alkanethiols on copper nanomembranes by submerged laser ablation

Abstract

Self-assembled monolayers (SAMs) of alkanethiols are major building blocks for nanotechnology. SAMs provide a functional interface between electrodes and biomolecules, which makes them attractive for biochip fabrication. Although gold has emerged as a standard, copper has several advantages, such as compatibility with semiconductors. However, as copper is easily oxidized in air, patterning SAMs on copper is a challenging task. In this work we demonstrate that submerged laser ablation (SLAB) is well-suited for this purpose, as thiols are exchanged in-situ, avoiding air exposition. Using different types of ω-substituted alkanethiols we show that alkanethiol SAMs on copper surfaces can be patterned using SLAB. The resulting patterns were analyzed by atomic force microscopy (AFM) and scanning electron microscopy (SEM). Both methods indicate that the intense laser beam promotes the exchange of thiols at the copper surface. Furthermore, we present a procedure for the production of free-standing copper nanomembranes, oxidation-protected by alkanethiol SAMs. Incubation of copper-coated mica in alkanethiol solutions leads to SAM formation on both surfaces of the copper film due to intercalation of the organic molecules. Corrosion-protected copper nanomembranes were floated onto water, transferred to electron microscopy grids, and

Photothermal Laser Microsintering of Nanoporous Gold

“…The annealing time in photothermal laser processing with microfocused CW lasers is determined by the local irradiation time, i.e., by the laser pulse length τ. Hence, the pore size d(t) can be estimated using the Einstein−Smoluchowski equation (7) where d 0 = 25 nm is the pore size of the native np-Au.…”

“…In the past decade, laser processing of nanomaterials has gained significant attention in nanotechnology. − This interest originates from two interrelated issues. On one hand, laser techniques provide a unique combination of powerful technical features in order to build up large-scale functional nanomaterials, , e.g., starting with ultrathin organic coatings, nanoparticles, polymers, and biomolecules. − On the other hand, the unique properties of nanomaterials allow one to improve the inherent limitations of laser techniques, e.g., the spatial resolution of laser patterning techniques. − , …”

Laser-Induced Functionalization of Organo/Carbon Interfaces for Selective Adsorption of Au Nanoparticles in Microsized Domains

“…Laser patterning of ultrathin organic coatings has attracted significant attention in the past decade. − Apart from the unique properties of SAMs and their prospects in micro- and nanofabrication, the general interest of these studies originates from the powerful technical features of laser patterning techniques, which makes them an indispensible tool in many fundamental studies and various technical and medical applications. − Sequential patterning techniques employing focused laser beams provide fast writing speeds and high flexibility. − Also, parallel processing of large areas has been demonstrated using microlens arrays and interference patterns. − More recent efforts addressed nanopatterning of organic monolayers, e.g., taking advantage of nonlinear effects resulting from multiphoton absorption processes or photothermally induced reactions. − The high thermal and chemical stability of silane-based SAMs offer unique opportunities in laser fabrication of nanostructured chemical patterns and architectures. , Photothermal micro- and nanoprocessing of alkylsiloxane monolayers, for example, has been demonstrated using ordinary microfocused CW lasers at wavelength in the visible range . Minimum structure sizes are below 100 nm …”

Photothermal Laser Fabrication of Micro- and Nanostructured Chemical Templates for Directed Protein Immobilization

“…15,16,18,19 In addition, direct patterning of glassthe preferred platform in many biomedical and biotechnical applicationsis feasible, and processing can be carried out in ambient air or in liquid environments, i.e., in aqueous solutions. 14,18,20 Micropatterning can be achieved following standard procedures. 18 Optimization of the laser parameters allows one to maximize the size of the fabricated structures.…”

“…Along this path distinct patterning techniques have been employed including photolithography, electron beam lithography, and scanning probe techniques. − More recently, also laser patterning have come into play. − The general interest in employing laser techniques originates from their peculiar set of technical features, which makes them a valuable tool in fundamental research as well as medical and technical applications ranging from implant fabrication to optical data storage . Generally, laser techniques offer fast processing speeds and a high degree of flexibility. , Also, parallel processing of large areas is feasible, e.g., using micro lens arrays or interference patterns. ,,, In addition, direct patterning of glassthe preferred platform in many biomedical and biotechnical applicationsis feasible, and processing can be carried out in ambient air or in liquid environments, i.e., in aqueous solutions. ,, Micropatterning can be achieved following standard procedures . Optimization of the laser parameters allows one to maximize the size of the fabricated structures .…”