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Growth And Structural Characterization Of Self Assembled Monolayers Sams On Gold Made From Functionalized Thiols And Selenols
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Book Synopsis Growth and Structural Characterization of Self-assembled Monolayers (SAMs) on Gold Made from Functionalized Thiols and Selenols by : Asif Bashir
Download or read book Growth and Structural Characterization of Self-assembled Monolayers (SAMs) on Gold Made from Functionalized Thiols and Selenols written by Asif Bashir and published by . This book was released on 2008 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Self-Assembled Monolayers on Gold Substrates by : Mihaela Georgeta Badin
Download or read book Self-Assembled Monolayers on Gold Substrates written by Mihaela Georgeta Badin and published by VDM Publishing. This book was released on 2008 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembled monolayers (SAMs) consist of densely packed long-chain organic molecules, which are chemisorbed on metal substrates through a sulfur head group. The purpose of this work, is to study the arrangement and structure of SAMs by IR, XPS, NEXAFS, STM, Ellipsometry and contact angle. While the first group of triptycenethiols and the second group of triarylaminethiols show a formation of disordered films on the gold surface, the third group of alkanethioacetates shows the formation of highly ordered monolayers. A further adsorption to upright oriented molecules is hindered due to kinetic effects. In the case of azo-molecules it is shown that the photoisomerization process is not reversible. These molecules are not able to form highly ordered monolayers on the gold surface due to the critical effect of azo-moiety.
Book Synopsis Self-assembled Monolayers on Gold Substrates Made from Functionalized Thiols and Dithiols by : Mihaela Georgeta Badin
Download or read book Self-assembled Monolayers on Gold Substrates Made from Functionalized Thiols and Dithiols written by Mihaela Georgeta Badin and published by . This book was released on 2007 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Self-assembled Monolayers for Biological Applications by : Adriana R. Kyvik
Download or read book Self-assembled Monolayers for Biological Applications written by Adriana R. Kyvik and published by . This book was released on 2018 with total page 217 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembled monolayers (SAMs) on gold surfaces have been designed, processed, characterized and used for specific biological studies. The studies performed include the control of lipid bilayer diffusion, cell adhesion and vascularization studies and also the creation of antimicrobial surfaces. More specifically, dynamic SAMs on surfaces whose properties can be modified with an electrochemical external stimulus have been developed and used to interrogate biological systems. The developed platform has been applied to two different applications to overcome present challenges when performing biological studies. Firstly, in Chapter 2, the design and synthesis of all the molecules needed to develop an electroactive platform, its processing as SAMs and the optimization of the surface confined redox process between a non-reactive Hydroquinone (HQ) termination and its corresponding reactive Benzoquinone (BQ) is reported. Two different interfacial reactions taking place on the electroactivated surfaces were studied in detail; the Diels-Alder (DA) and the Michael Addition (MA) interfacial reactions, with cyclopentadiene (Cp) or thiol tagged molecules, respectively. The comparative study between DA and MA as surface functionalization strategies with a temporal control reveal that even though MA is not commonly used for this purpose it offers an attractive strategy for stimulus activated functionalization for biological applications. In Chapter 3, the developed platform has been used to achieve a temporal control of cell adhesion and in this way mimic in vivo conditions more accurately. Cell adhesion plays fundamental roles in biological functions and as such, it is important to control cell adhesion on materials used for biomedical applications. Towards this aim, the dynamic interface developed has been used to immobilize cell adhesion promoting peptides through the two different interfacial reactions, namely the DA and the MA reaction, and a comparative study has been carried out. Moreover, a study involving immobilized VEGF-mimicking peptide Qk has been conducted demonstrating the possibility of using the novel peptide for directing cell differentiation into tubular networks for in vitro platforms, by attaching them on a surface. In Chapter 4, we have used the developed electroactive interface to control the dynamics of lipid bilayers as cell membrane models, designed for transmembrane protein characterization in a more in vivo like environment. Specifically, electroactive SAMs have been used to control the moment in which tethering of lipid bilayer deposited on them occurs and consequently decrease its diffusion. In this way, proteins and lipids can maintain their fluidity until tethering is desired, a useful platform for transmembrane protein characterization. iii Finally, in Chapter 5, a surface biofunctionalization strategy also based on SAMs has been used to produce a bactericidal surface by successfully immobilizing novel antimicrobial proteins produced by recombinant DNA technology. This is relevant in view of the verge of an imminent antibiotics crisis. To confirm the antimicrobial activity and biofilm growth prevention of these surfaces, a biofilm assay was performed demonstrating that proteins retain their antimicrobial effect when immobilized. All these strategies open new possibilities for controlled biomolecule immobilization for fundamental biological studies and for applications in biotechnology, in the interface of materials science and biology.
Book Synopsis Characterization of Self-Assembled Monolayers by Low Energy Reactive Ion Scattering: Influences of Terminal Group Composition and Structure on Ion-Surface Interaction by : Yang, Xi
Download or read book Characterization of Self-Assembled Monolayers by Low Energy Reactive Ion Scattering: Influences of Terminal Group Composition and Structure on Ion-Surface Interaction written by Yang, Xi and published by . This book was released on 2007 with total page 534 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low energy (tens of eV) polyatomic cations were used as probes for characterization of monolayers of spontaneously chemisorbed thiols on gold. Characteristics including chemical composition, surface order and orientation of the self-assembled monolayers (SAMs) can be derived by monitoring the products of projectile ion neutralization, surface-induced dissociation (SID), and ion-surface reactions. To study the influence of the terminal group chemical structures and orientations of the SAMs on ion-surface interactions, a series of semi-fluorinated alkane thiols with difluoromethylenes buried underneath hydrocarbon terminal groups were examined (CH3CF2CH2− and CH3CH2CF2−). Compared to terminally fluorinated SAMs, they showed more projectile ion neutralization and less internal to vibrational energy deposition into precursor ions. Projectile ion-hydrocarbon reactions decreased significantly when difluoromethylenes are one or two bonds away from the terminal group. Furthermore, ion-surface reaction results on surfaces with odd and even chain lengths suggested that they have similar terminal methyl orientations to their hydrocarbon counterparts. Mixed monolayers of CF3CF2(CH2)14SH (F-SAMs) and CH3(CH2)15SH (H-SAMs) with systematically changing electron transfer, energy deposition and ion-surface reaction were prepared using mixed thiols solution and micro-contact printing (μ-CP). The solution mixture system showed linear variations in electron transfer and energy deposition with different F-SAM surface concentrations, while non-linear changes occur for ion-surface reaction suggesting strong lateral interactions between the two components. These interactions are minimized in theμ-CP system containing domains of each thiol. Energy deposition on the patterned surfaces varies non-linearly with changing F-SAM concentration which differs from the homogenously mixed system. To explore SID with a 90 collision angle, eV SID of a series of protonated peptide ions were performed in an in-line sector Time-Of-Flight (TOF) mass spectrometer. The results were compared to keV collision-induced dissociation (CID) data collected with the same instrument. Fragmentation efficiency for SID was higher than CID for those peptides. In addition to the excellent control over laboratory collision energies with SID, different amount of energy deposition can be achieved when varying surface composition, e.g. using mixed F-SAM/H-SAM. Reactive ion scattering spectrometry (RISS) results provided more in-depth knowledge of low energy ion-surface interactions that will promote usage of RISS as a novel surface characterization technique.
Book Synopsis The Formation, Structural Dynamics, and Surface Properties of Thiol/gold Self Assembled Monolayers by : David Stephen Karpovich
Download or read book The Formation, Structural Dynamics, and Surface Properties of Thiol/gold Self Assembled Monolayers written by David Stephen Karpovich and published by . This book was released on 1996 with total page 340 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Helical, Disordered, and What that Means: Structural Characterization of a New Series of Methyl 1-Thiaoligo(ethylene Oxide) Self-Assembled Monolayers by : David J. Vanderah
Download or read book Helical, Disordered, and What that Means: Structural Characterization of a New Series of Methyl 1-Thiaoligo(ethylene Oxide) Self-Assembled Monolayers written by David J. Vanderah and published by . This book was released on 2002 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembled monolayers (SAMs) of a series of linear thiols containing a 1= thiaoligo(ethylene oxide) TOEO moiety, i.e., HS(CH2CH2O)(x)CH3, where x = 3 - 6, were prepared on polycrystalline gold (Au) and characterized by reflection absorption infrared spectroscopy (RAIRS) and spectroscopic ellipsometry (SE). For x = 5 and 6, the RAIRS data show that the TOEO segment, oriented normal to the substrate, adopts the highly ordered 7/2 helical structure of the folded-chain crystal polymorph of poly(ethylene oxide). For x = 3 and 4, the RAIRS and SE data indicate disordered, "amorphous" SAMs with essentially no evidence of the helical conformation in the TOEO segment. These data suggest that, for SAMs with TOEO segments, a minimum of five ethylene oxide units is required to adopt a helical conformation.
Book Synopsis Preparation and Characterization of Alkanethiolate Self-assembled Monolayers Onto Gold from Environmentally Benign Solvents by : Dong Yan
Download or read book Preparation and Characterization of Alkanethiolate Self-assembled Monolayers Onto Gold from Environmentally Benign Solvents written by Dong Yan and published by . This book was released on 2002 with total page 374 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Tuning Surface Properties Using Self-assembled Monolayers for Various Applications by : Yekaterina Leonidovna Lyubarskaya
Download or read book Tuning Surface Properties Using Self-assembled Monolayers for Various Applications written by Yekaterina Leonidovna Lyubarskaya and published by . This book was released on 2014 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The research presented in this dissertation focuses on the study of self-assembled monolayers (SAMs) in the modification of surface properties of different substrates for various applications. Self-assembled monolayers are organic molecules that can be deposited on a variety of surfaces, such as those of metals, metal-oxides, and semiconductors. Formation of SAMs on any inorganic material provides a ubiquitous way to impart desirable chemical and physical properties of organic and biological molecules to the inorganic substrate. It has been demonstrated that single molecules and their self-assembled monolayers can significantly alter the physical and electronic properties of inorganic conductors; moreover, studies have shown that the performance of many electrical devices can be transformed by modifying inorganic electrodes with organic SAMs. This is especially important for the development of next generation of ultra-compact electronic devices, in which the ability to control the interfacial charge-transport with a single monolayer of organic molecules would be ideal. We have developed different organic electronic architectures as test beds for studying the effect of monolayer properties, such as structural and geometrical parameters, on their electronic properties. By using a typical organic electronic device as a sensitive test platform, slight changes in a monolayer property, such as length, have been detected by studying the current- voltage characteristics (JV) of organic diodes functionalized with self-assembled monolayers (SAMs) of varying alkyl chain-length. Next, we describe the application of SAMs based on n-octylphosphonic acid (C8PA) and 1H,1H,2H,2H-perfluorooctanephosphonic acid (PFOPA) as anode buffer layers in C60-based organic photovoltaic (OPV) devices. We used the OPV platform to compare stabilities of organic monolayers exposed to ambient conditions with SAMs positioned inside working OPV devices. We found that the stabilities are different, suggesting the degradation mechanisms are distinct. The degradation of the OPV efficiency with respect to air exposure was significantly reduced with the perfluorinated PFOPA compared to the aliphatic C8PA. We attributed the OPV degradation to moisture diffusion from the top aluminum electrode and we discuss that the lowering of the anode work function is the result of hydrolysis of the SAM buffer layer. Next, we demonstrated the dependence of molecular electronic properties on the functional group substitution and that the changes in these properties can be measured using the organic light-emitting (OLED) platform. Specifically, we compared bilayered organic monomolecular systems immobilized on an inorganic electrode as the charge-injecting components of the organic light emitting diodes (OLEDs). Our bilayered interfaces comprise ordered inert primary and functional reactive layers, and they differ in only one parameter: the molecular structure of the terminal functional group. We demonstrate that we can visualize the differences in the charge transfer dynamics of two bilayered systems via patterned electroluminescence. In addition, we describe a new protocol for the preparation of shape-controlled multicomponent particles comprising metallic (Au and Ti), magnetic (Ni), and oxide (SiO2, TiO2) layers. First, we discuss the application and attractiveness of the colloidal structures, Janus Particles (JPs), that possess two different surfaces, varying either in polarity, hydrophilicity, etc. Next, we present our method for specifically controlling the composition, shape, and size of the micro-JPs. We demonstrate how this protocol permits fabrication of non-symmetrical particles by orthogonally functionalizing their opposite sides using well-established organosilanes and thiol chemistries (based on SAMs). We propose that these colloids may be used as convenient materials for studying non-symmetrical self-assembly at the meso- and micro-scales, due to their unique geometries and surface chemistries"--Pages viii-x.
Book Synopsis Intermolecular Interactions and Surface Properties of Self-Assembled Monolayers of Functional Boron Clusters by : Dominic Pascal Goronzy
Download or read book Intermolecular Interactions and Surface Properties of Self-Assembled Monolayers of Functional Boron Clusters written by Dominic Pascal Goronzy and published by . This book was released on 2019 with total page 242 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembled monolayers (SAMs) are an advantageous platform for probing the fundamental interactions that dictate the spontaneous formation of nanostructures and supramolecular assemblies and directly affect macroscale properties. As such, SAMs provide an avenue for creating surfaces with defined chemical and physical properties. The assembly of these nanoscale constructs is driven by three primary factors: the interface between the substrate and the monolayer, the interactions between the adsorbate molecules, and the interface between the monolayer and the environment. I studied an icosahedral cage boron cluster, the carborane, as a building block for SAMs with properties that we can tune to advantage. Carboranes have several favorable traits, including providing a scaffold for a variety of functional groups. A chalcogenide group, typically a thiol, is used for surface attachment; moreover, bifunctional carboranes also enable control of the valency during assembly and greater reactivity at the environmental interface of the SAM. Additionally, isomers of carboranethiol have distinct dipole moments in terms of orientation and magnitude. The dipoles can lead to the formation of long-range dipole dipole networks within the SAM, which can stabilize the SAM and also modify the surface properties of the material. The rigid, symmetric backbone of the carborane cage results in SAMs that are relatively pristine and defect free. Due to these advantageous traits, carboranes enable the creation of monolayers with tunable interactions at the SAM interfaces. This system not only enables myself and others to study the molecular forces of assembly but also facilitates the simultaneous modification of both chemical and physical properties of surfaces and interfaces. This thesis describes several carborane based surface assemblies and the variable interactions they have within the SAM interfaces. The introduction of a second thiol group to the carborane cage can be used to modulate the interaction of the SAM with the substrate. Carboranedithiol SAMs exhibit two binding modes, a monovalent state and a divalent state. The presence of these two modes enables tuning of valency using acid base chemistry and thus the ratio of singly bound to dual bound surface molecules can be modified during deposition. Another avenue to alter the interactions at the substrate-monolayer interface is to use an alternative functional group for surface attachment. A chalcogenide group similar to thiol is selenol, however carboraneselenolate SAMs have a distinct surface morphology compared to carboranethiolate SAMs. Carboraneselenolate SAMs exhibit a dynamic double lattice where surface molecules appear to switch between high- and low-conductance binding modes. This morphology is consistent with other cage molecule selenolate SAMs and is typically associated with substrate-mediated interactions. In contrast, the carboraneselenolate SAMs are resistant to thermal rearrangement and desorption due to the dipole dipole interactions within the monolayer. Carboranethiols can be modified by adding a carboxylic acid functional group that both alter the interactions within the monolayer and provide a platform for further reactions at the environmental interface. The introduction of a laterally positioned carboxyl functional group increases the steric demands of the molecule, thereby decreasing the packing density, but also enables hydrogen bonding interactions within the monolayer. The pKa of the surface bound carboxylic acid is shifted such that it is approximately two pH units less acidic than in solution. This shift is driven by the dielectric of the environment that the carboxyl group experiences on the surface, which is determined by the intermolecular interactions within the monolayer, partial desolvation, and the proximity to the substrate surface. The carboxyl group also remains available for further chemistry on the surface and can coordinate with a variety of metal ions or be used as an attachment point for performing chemical lift off lithography (CLL). This lithographic technique was performed successfully on several types of carboxyl carboranethiolate SAMs. The use of these SAMs also enabled the characterization of the post CLL substrate surface via scanning tunneling microscopy. This analysis revealed the molecules left behind during the CLL process are either in small molecular islands or sparsely packed, highly mobile molecules. There remain many opportunities for further chemistry to be performed with these carboxyl terminated SAMs or with carboranethiol SAMs with other additional functional groups. Carborane-based SAMs are a versatile system that provides a high degree of tunability at all three interfaces of a SAM. The work presented lays the foundation for further application in lithography, like CLL, as well as the use of these SAMs in organic electronics and devices and as interfacial materials.
Book Synopsis Structural Characterization of Self-assembled Monolayers Within Molecular Junctions by : Paula Elena Colavita
Download or read book Structural Characterization of Self-assembled Monolayers Within Molecular Junctions written by Paula Elena Colavita and published by . This book was released on 2005 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis The Formation, Structural Dynamics, and Surface Properties of Thiol/gold Self Assembled Monolayer by : David Stephen Karpovich
Download or read book The Formation, Structural Dynamics, and Surface Properties of Thiol/gold Self Assembled Monolayer written by David Stephen Karpovich and published by . This book was released on 1996 with total page 153 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Investigation of the Structure of Alkyne Self-assembled Monolayers on Gold and the Development of Matrix-enhanced Secondary Ion Mass Spectrometry Methods by : Jennifer Joan Dertinger
Download or read book Investigation of the Structure of Alkyne Self-assembled Monolayers on Gold and the Development of Matrix-enhanced Secondary Ion Mass Spectrometry Methods written by Jennifer Joan Dertinger and published by . This book was released on 2012 with total page 854 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of thin films is critical to the understanding of many technological and biological processes. The focus of this dissertation is to develop methods to characterize very low concentration species present on surfaces. A reflection adsorption infrared spectroscopy (RAIRS) system was constructed and tested. The instrument comprises an Fourier transform infrared (FTIR) spectrometer, an optical pathway and a vacuum chamber. The RAIRS system is designed to investigate in situ the interaction of vapor-deposited metals and gases, such as CVD precursors, with organic thin films, and so a vacuum chamber is required. To accommodate the vacuum chamber, an external IR optical pathway was designed and assembled because there was not enough room in the internal optical pathway of the FTIR spectrometer. The synthesis and characterization of terminal alkyne monolayers (TAMs) adsorbed on gold was investigated by RAIRS, single wavelength ellipsometry, time-of-flight secondary ion mass spectrometry (TOF SIMS) and x-ray photoelectron spectroscopy (XPS). TAMs have the potential to transform surface functionalization for many technological applications because they have increased temperature stability and electrical conductance. However, the data suggest that TAMs are not well-ordered and can be oxidized, which may limit their application. For TAMs with less than 11 methylene units in the backbone, the adsorbed layer is highly disordered, oxidized and has a multilayer structure. Longer chain length TAMs form disordered monolayers on gold. As the methylene chain length increases, the conformational order of the TAMs increases with the alkynes in an upright conformation and bound to the surface via a Au-C[identical to]C- bond. The use of room temperature ionic liquids (ILs) as matrices in TOF SIMS was examined to further characterize biological thin films. The data indicate that the secondary ion intensities of lipids, steroids, peptides, proteins and proteins are significantly enhanced using IL matrices. Secondary ion enhancements of at least an order of magnitude are typically observed. Limits of detection are also greatly improved. For example, the limits of detection of 1,2-dipalmityl-sn-glycero-phosphocholine (DPPC) and 1,2-dipalmityl-sn-glycero-phosphoethanolamine (DPPE) were at least two orders of magnitude better. The data also show that ILs are suitable matrices for imaging SIMS. The IL matrices did not cause changes to the sample surface; no "hot spots" were observed. The mechanism of the secondary ion intensity enhancements using IL matrices was then investigated to optimize use in characterization. Only protic ILs, which are formed by the transfer of a proton from a Brønsted acid to base, were observed to increase analyte signals. The matrix enhancement mechanism therefore involves the transfer of protons from, or to, the analyte, to, or from the matrix. The magnitude of the analyte signal enhancements is dependent on the chemistry of the matrix cation, anion and analyte. The pKa of the matrix acid and base do not appear to have a strong effect on the ion-intensity enhancements. The results also indicate that the chemical identity of the matrix anion has a stronger effect on analyte signal enhancements than the matrix cation.
Book Synopsis Intra-Monolayer Hydrogen-Bonding in Monolayer Protected Gold Clusters by : Andrew K. Boal
Download or read book Intra-Monolayer Hydrogen-Bonding in Monolayer Protected Gold Clusters written by Andrew K. Boal and published by . This book was released on 2001 with total page 6 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unlike the highly ordered Self-Assembled Monolayers (SAMs) formed on flat gold surfaces those on gold nanoparticles radiate from a roughly spherical center and are amorphous in structure. One result of this structural motif is that the strength of intra-monolayer non-covalent interactions, such as pi-stacking and hydrogen bonding, are a function of the distance of the recognition element from the colloidal core. We present here an exploration of these phenomena in amide functionalized thiols in MPCs where the amide functionality position was varied in the alkane chain.
Book Synopsis Monolayer Films Prepared by the Spontaneous Self-Assembly of Symmetrical and Unsymmetrical Dialkyl Sulfides from Solution Onto Gold Substrates: Structure, Properties, and Reactivity of Constituent Functional Groups by : Ernest B. Troughton
Download or read book Monolayer Films Prepared by the Spontaneous Self-Assembly of Symmetrical and Unsymmetrical Dialkyl Sulfides from Solution Onto Gold Substrates: Structure, Properties, and Reactivity of Constituent Functional Groups written by Ernest B. Troughton and published by . This book was released on 1987 with total page 88 pages. Available in PDF, EPUB and Kindle. Book excerpt: Exposure of evaporated gold films supported on silicon wafers to solutions of dialkyl sulfides (R(CH2)m-S-(CH2)n-R'; R and R'=CH3 or CO2H) or alkyl thiols (R(CH2)nSH, R=CO2H or CH3) in methanol or ethanol results in rapid formation of a monolayer of the organosulfer compound adsorbed onto the gold. The resulting films have been characterized using a number of techniques, including X-ray photoelectron spectroscopy (XPS), infrared spectroscopy (IRS), ellipsometry, and wetting. These self-assembled, supported organic monolayer films are systems that can be used to study problems in the physical-organic chemistry and materials science of organic surfaces, especially the relation between the molecular-level structure of the film constituents and the macroscopic properties of the assembled monolayers. Keywords: Thin film, Monolayer, Surface spectroscopy, electronic materials.
Book Synopsis Structure, Stability, and Reactivity of Self-assembled Monolayers on AU(111) by : Lili Duan
Download or read book Structure, Stability, and Reactivity of Self-assembled Monolayers on AU(111) written by Lili Duan and published by . This book was released on 2001 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Book Synopsis Rapid Degradation of Alkanethiol-Based Self-Assembled Monolayers on Gold in Ambient Laboratory Conditions by :
Download or read book Rapid Degradation of Alkanethiol-Based Self-Assembled Monolayers on Gold in Ambient Laboratory Conditions written by and published by . This book was released on 2004 with total page 23 pages. Available in PDF, EPUB and Kindle. Book excerpt: Self-assembled monolayers (SAMs) consisting of alkanethiols and similar sulfur-containing molecules on noble metal substrates are extensively used and explored for various chemical and biological surface-functionalization in the scientific community. SAMs consisting of thiol- or disulfide-containing molecules adsorbed on gold are commonly used due to their ease of preparation and stability. However, the gold-thiolate bond is easily and rapidly oxidized under ambient conditions, adversely affecting SAM quality and structure. Here, the oxidation of dodecanethiol on gold is explored for various 12-hour exposures to ambient laboratory air and light. SAM samples are freshly prepared, air-exposed, and stored in small, capped vials. X-ray photoelectron spectroscopy (XPS) reveals nearly complete oxidation of the thiolate in air-exposed samples, and a decrease in carbon signal on the surface. Near-edge X-ray absorption fine structure spectroscopy (NEXAFS) at the Carbon K-edge shows a loss of upright orientational order upon air-exposure. Alternatively, the oxidation of the thiolate is minor when SAMs are stored in limited-air-containing small 15 ml vials. Thus, care must be taken to avoid SAM degradation by ensuring alkanethiolates on gold have sufficient durability for each intended environment and application.
