Thermo-Kinetics Study of Laser-Induced Desorption of Self-Assembled Monolayers from Gold:  Case of Laser Micropatterning

Shadnam, Mohammad Reza; Kirkwood, Sean E.; Fedosejevs, R.; Amirfazli, Alidad

doi:10.1021/jp0500642

Cited by 20 publications

(21 citation statements)

References 23 publications

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“…Deviation in the size of the major axis was large enough to shield any elongation in pattern length induced by changing the laser parameters therefore linear increases in both the minor axis and pattern area with increased laser fluence were observed (Figure 3A, C). The minor axis linearly increased with increased laser fluence at a constant number of iterations (Figure 3A) as reported by others 27, 31, 35. When patterning over a fluence range of 12.80–50.80 nJ μm −2 with a constant 1000 iterations per ROI, the minor axis increased from 2.19 ± 0.26 to 3.03 ± 0.18 μm (Figure 3A).…”

Section: Resultssupporting

confidence: 83%

“…Laser‐assisted thermally‐induced SAM desorption from Au surfaces has been confirmed by secondary ion mass spectro‐scopy,29 cyclic voltammetry,30 condensation,27–29 scanning electron microscopy,27, 30, 31, 35 fluorescence,28 and atomic31 or lateral force microscopies 28. In this study, surface mapping X‐ray photoelectron spectroscopy (XPS) was implemented to verify laser‐induced thermal desorption of an OEG SAM in the patterned ROIs through analysis of the C 1s , O 1s , and S 2p spectra to monitor the presence of the alkyl chain, oligo(ethylene glycol) terminal group, and thiol head group respectively.…”

Section: Resultsmentioning

confidence: 86%

“…The conductivity can diminish by a factor of ∼2× when the thickness decreases from 30 to 6 nm as a result of changes in grain morphology 34. Laser‐induced thermal desorption of SAMs occurs when the energy of the light adsorbed by the Au film is released as heat resulting in a highly localized increase in surface temperature in the irradiated region 27, 35. Approximately 50% of the SAM is removed at a surface temperature of 160 °C36 with complete desorption occurring at 210–212 °C 27, 36.…”

Section: Resultsmentioning

confidence: 99%

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Fabrication of Multifaceted Micropatterned Surfaces with Laser Scanning Lithography

Slater

Miller

et al. 2011

Adv Funct Materials

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The implementation of engineered surfaces presenting micrometer-sized patterns of cell adhesive ligands against a biologically inert background has led to numerous discoveries in fundamental cell biology. While existing surface patterning strategies allow for pattering of a single ligand it is still challenging to fabricate surfaces displaying multiple patterned ligands. To address this issue we implemented Laser Scanning Lithography (LSL), a laser-based thermal desorption technique, to fabricate multifaceted, micropatterned surfaces that display independent arrays of subcellular-sized patterns of multiple adhesive ligands with each ligand confined to its own array. We demonstrate that LSL is a highly versatile “maskless” surface patterning strategy that provides the ability to create patterns with features ranging from 450 nm to 100 μm, topography ranging from -1 to 17 nm, and to fabricate both stepwise and smooth ligand surface density gradients. As validation for their use in cell studies, surfaces presenting orthogonally interwoven arrays of 1×8 μm elliptical patterns of Gly-Arg-Gly-Asp-terminated alkanethiol self-assembled monolayers and human plasma fibronectin are produced. Human umbilical vein endothelial cells cultured on these multifaceted surfaces form adhesion sites to both ligands simultaneously and utilize both ligands for lamella formation during migration. The ability to create multifaceted, patterned surfaces with tight control over pattern size, spacing, and topography provides a platform to simultaneously investigate the complex interactions of extracellular matrix geometry, biochemistry, and topography on cell adhesion and downstream cell behavior.

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Section: Resultssupporting

confidence: 83%

Section: Resultsmentioning

confidence: 86%

Section: Resultsmentioning

confidence: 99%

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Fabrication of Multifaceted Micropatterned Surfaces with Laser Scanning Lithography

Slater

Miller

et al. 2011

Adv Funct Materials

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“…13, the local reaction kinetics depends on the irradiation time τ and the rate constant k ( r ) , which itself depends on the temperature. At a constant irradiation time, a certain temperature is required in order to induce substantial desorption of thiol molecules [21–22 37]. Following Equations 3–11 this necessitates a critical laser power density.…”

Section: Resultsmentioning

confidence: 99%

Substrate-mediated effects in photothermal patterning of alkanethiol self-assembled monolayers with microfocused continuous-wave lasers

Schröter¹,

Kalus²,

Hartmann³

2012

Beilstein J. Nanotechnol.

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SummaryIn recent years, self-assembled monolayers (SAMs) have been demonstrated to provide promising new approaches to nonlinear laser processing. Most notably, because of their ultrathin nature, indirect excitation mechanisms can be exploited in order to fabricate subwavelength structures. In photothermal processing, for example, microfocused lasers are used to locally heat the substrate surface and initiate desorption or decomposition of the coating. Because of the strongly temperature-dependent desorption kinetics, the overall process is highly nonlinear in the applied laser power. For this reason, subwavelength patterning is feasible employing ordinary continuous-wave lasers. The lateral resolution, generally, depends on both the type of the organic monolayer and the nature of the substrate. In previous studies we reported on photothermal patterning of distinct types of SAMs on Si supports. In this contribution, a systematic study on the impact of the substrate is presented. Alkanethiol SAMs on Au-coated glass and silicon substrates were patterned by using a microfocused laser beam at a wavelength of 532 nm. Temperature calculations and thermokinetic simulations were carried out in order to clarify the processes that determine the performance of the patterning technique. Because of the strongly temperature-dependent thermal conductivity of Si, surface-temperature profiles on Au/Si substrates are very narrow ensuring a particularly high lateral resolution. At a 1/e spot diameter of 2 µm, fabrication of subwavelength structures with diameters of 300–400 nm is feasible. Rapid heat dissipation, though, requires high laser powers. In contrast, patterning of SAMs on Au/glass substrates is strongly affected by the largely distinct heat conduction within the Au film and in the glass support. This results in broad surface temperature profiles. Hence, minimum structure sizes are larger when compared with respective values on Au/Si substrates. The required laser powers, though, are more than one order of magnitude lower. Also, the laser power needed for patterning decreases with decreasing Au layer thickness. These results demonstrate the impact of the substrate on the overall patterning process and provide new perspectives in photothermal laser patterning of ultrathin organic coatings.

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“…Direct laser patterning of alkanethiols is a newer alternative patterning method. [19][20][21] We present a process, named submerged laser ablation (SLAB), which enables the preparation of complex patterned SAMs (Scheme 1), free gold areas suitable as electrodes, and in addition laser patterning of the substrate itself in a single process. With the SLAB process any contamination arising from metal particles formed during laser ablation is avoided.…”

mentioning

confidence: 99%

Solid‐Supported Multicomponent Patterned Monolayers

Rhinow

Hampp

2007

Advanced Materials

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Microarray technology is a rapidly developing field and a powerful tool in genome and proteome analysis and drug screening. [1][2][3][4] Although several types of microarrays of oligonucleotides and peptides have been constructed, surface patterning methods are still a key challenge in the field of 'biochip' fabrication. Self-assembled monolayers (SAMs) of alkanethiols on gold surfaces are widely used in nanotechnology and serve as templates for the immobilization of biomolecules.[5] UV lithography is a well-established patterning scheme for SAMs [6][7][8] but less suitable for smaller series. Mechanical methods for patterning of SAMs have been developed and overcome this problem. Among them, microcontact printing [9] (lCP) and dip-pen nanolithography [10] are the most prominent ones. Although with lCP spatial resolutions better than 100 nm have been achieved, it is difficult to use lCP for multistep patterning procedures. Dip-pen nanolithography in turn is limited in speed. Attempts have been made to increase the speed of dip-pen methods by massive parallelization.[11]Electron-beam (e-beam) technology has attracted the interest of several groups, [12,13] and high-resolution structures were realized, but the equipment is very costly. Other techniques, such as X-ray lithography, [14] ink-jet printing [15,16] as well as nanografting, [17] and even near-field lithography, [18] were explored for this challenging task. Direct laser patterning of alkanethiols is a newer alternative patterning method. [19][20][21] We present a process, named submerged laser ablation (SLAB), which enables the preparation of complex patterned SAMs (Scheme 1), free gold areas suitable as electrodes, and in addition laser patterning of the substrate itself in a single process. With the SLAB process any contamination arising from metal particles formed during laser ablation is avoided. Monolayers made from a wide spectrum of molecules may be processed by this method. The only requirement of the molecules is that they carry a thiol group, which enables their reaction with gold. As the gold substrate layer may also be structured in the same process (at higher energies), the SLAB process may be useful in the preparation of various types of 'biochips'.A template-stripped gold (TSG) substrate, mounted onto a glass carrier by epoxy glue, is first covered with a SAM of a thiol (primary thiol). The assembly is then submerged into a solution of a second thiolated compound (secondary thiol or reactant). The laser beam incidents the TSG by passing through the reactant solution and the SAM formed by the first thiol. The area of gold surface where the laser beam hits is heated due to the partial absorption of the laser light. The intensity is chosen to be low enough not to cause any ablation process in the TSG layer itself but high enough to thermally split the sulfur-gold bond, which binds the primary thiol to the TSG substrate. The primary thiol is released from the surface in the direction of the laser beam movement. As soon as the laser beam proceeds...

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Thermo-Kinetics Study of Laser-Induced Desorption of Self-Assembled Monolayers from Gold: Case of Laser Micropatterning

Cited by 20 publications

References 23 publications

Fabrication of Multifaceted Micropatterned Surfaces with Laser Scanning Lithography

Fabrication of Multifaceted Micropatterned Surfaces with Laser Scanning Lithography

Substrate-mediated effects in photothermal patterning of alkanethiol self-assembled monolayers with microfocused continuous-wave lasers

Solid‐Supported Multicomponent Patterned Monolayers

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