Octadecyl Mercaptan Research Articles

A Nano Needle-like Hydrophobic Co3O4@SSM for Heavy Oil Water Separation with High Efficiency

The needles-like Co3O4 with micro nano structure was synthesized by hydrothermal method and calcination. After being modified by octadecyl mercaptan, it shows an ultra-high separation efficiency of more than 99.9% for Dichloromethane, 1,2-Dichloroethane and Trichloromethane oil/water mixtures. We believe this metal- based separation membrane will provide significant reference for further practical research. The Co3O4 with the needles-like micro nano structures is generated on stainless steel mesh by hydrothermal method and calcination, and then modified by octadecylmercapta(ODT), which changed Co3O4 structure from hydrophilic wettability to nearly superhydrophobicity. The Co3O4@SSM shows excellent heavy oil-water separetion eefficiency to three different kinds (dichloromethane, 1,2-dichloroethane and trichloromethane) of heavy oil/water mixture for 10 cycles.

Hydrophobic cotton fabric synthesized via dispersion polymerization from poly(glycidyl methacrylate) nanoparticles for self-cleaning applications

In this study, we developed a facile, efficient, and eco-friendly strategy for fabricating hydrophobic cotton fabrics using poly(glycidyl methacrylate) (PGMA) nanoparticles (NPs), which were synthesized via a radical-induced dispersion polymerization technique. Interestingly, the long alkyl chain of octadecyl mercaptan provides a low surface free energy, while PGMA NPs act as anchors, forming covalent bonds with the surface of the cotton fabric, resulting in greater roughness. The covalent bonds, formed via the epoxy ring-opening reaction between the glycidyl groups of the PGMA NPs, react with the hydroxyl groups on the surface of the cotton fabric. The chemical structure, morphology, and mechanical properties of the fabric were characterized using solid-state nuclear magnetic resonance spectroscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, scanning/transmission electron microscopy, energy-dispersive spectroscopy, Brunauer-Emmett-Teller analysis, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Mechanical characterizations suggested that the tear strength decreased for the modified fabric, whereas the stiffness was double that of neat cotton. The modified cotton fabric exhibited nano- and microscale roughness, which resulted in increased hydrophobicity, with a contact angle of 130°. The modified cotton exhibited self-cleaning properties and various droplet resistance properties, and thus has promising applications in different fields.

Preparation of superhydrophobic nylon-56/cotton-interwoven fabric with dopamine-assisted use of thiol-ene click chemistry.

With the help of dopamine, we constructed a hydroxyl-rich secondary reaction platform on a surface formed by interwoven nylon 56 and cotton fibres. Octadecyl mercaptan and vinyl trimethoxysilane (VTMS) are used for the click coupling preparation of superhydrophobic reagents, which are grafted onto polydopamine aggregates and successfully used to prepare superhydrophobic nylon 56/cotton-interwoven fabric. The static contact angle was 161° and the sliding angle was 8°. Note that the prepared superhydrophobic fabric can withstand corrosive liquids, water washing, ultraviolet radiation and mechanical abrasion, it has excellent superhydrophobic stability, and self-cleaning and oil–water-separation functionalities. This simple, fast and environmentally friendly method can be applied to other substrates and shows tremendous potential for expanding the field of superhydrophobic applications.

Fabrication of Robust Water-Repellent Technology on Cotton Fabric via Reaction of Thiol-ene Click Chemistry

A robust superhydrophobic fabric coating was fabricated on cotton fabric under UV light, which was achieved by convenient surface modification with mercaptopropyltriethoxysilane, tetramethyltetravinylcyclotetrasiloxane, and octadecyl mercaptan. The modification of cotton fabric with 3-mercaptopropyltriethoxysilane introduces reactive mercapto groups, after which 2,4,6,8-tetramethyltetravinylcyclotetrasiloxane reacts with mercapto groups, and octadecyl mercaptan provides microscale roughness. The nonpolar carbon chains of thiol cause the cotton to have a low surface energy. As reported, the combination of microscale roughness with low surface energy has a superhydrophobic effect on cotton, which leads to a high contact angle of 161.8° and sliding angle of 8°. Infrared spectroscopy, XPS, and SEM tests were used to characterize the chemical structure and morphological changes of the surface of cotton fabric before and after click reaction. The fabric after click reaction exhibited an oil–water mixture separation ability owing to its superhydrophobicity. Thus, the finished fabric could be used in the oil–water separation field. Importantly, the superhydrophobic textile displays resistance to laundering, mechanical abrasion, strong acidic and alkaline environments, and UV irradiation. We hope that this study can broaden the real-life applications of cotton fabric.

Kinetics of radical telomerization of acrylic acid in the presence of 1-octadecanethiol

Abstract The oligomer of acrylic acid with a thiooctadecyl end-group was obtained by using octadecyl mercaptan as the chain-transfer agent. The resulting oligomer was characterized by 1H NMR and 13C NMR spectroscopy and critical micelle concentration was determined in aqueous solution. The order with respect to the initiator concentration was 0.5 and 1.6 with respect to the monomer concentration. The abnormal reaction order with respect to the monomer concentration was explained by participation in the chain propagation of unassociated and associated forms of acrylic acid, which were stabilized by formation of hydrogen bonds. The kinetic parameters of telomerization were determined. Telomerization with acrylic acid in the non-associated form had lower activation energy and lower pre-exponential factor than in the case of associated forms. The synthesis of the acrylic acid oligomer with a thiooctadecyl end-group having a low critical micelle concentration in water was carried out in one stage and corresponds to the concept of atom economy.

Fabrication of superhydrophobic surfaces on zinc substrates

Stable superhydrophobic surfaces were fabricated on the zinc substrates through simple silver replacement deposition process with the modification of octadecyl mercaptan. The effects of reaction conditions on the surface morphology and wettability of the prepared surfaces were carefully studied. The results show that the fabrication of a best superhydrophobic surface depends largely on the moderate reactant concentration. When the concentration of AgNO 3 solution was 2 mmol/L, the zinc substrate was covered by a dendritic outline structure. Aggregated silver nanoparticles were formed on the substrate in accordance with some certain laws, exhibiting great surface roughness. The typical hierarchical micro-nanostructures, flower-like structures and porous structures also could be found from the SEM images. The maximal water contact angle (CA) value of about 161 ± 2°, and the minimal sliding angle (SA) of about 2° were obtained under the same reaction condition.

Infrared Ellipsometry of Self-Assembled Octadecylmercaptan on Gold Films and Nanoislands: Effects of Thickness and Morphology of the Gold Layer

Infrared spectroscopic ellipsometry (IRSE) of organic self-assembled monolayers (SAMs) commonly uses the external reflection geometry and a three-phase system (bulk substrate, SAM, and ambient medium). In the present work, we study a four-phase system for IRSE, where a gold substrate film is sandwiched between a CaF2 prism and a SAM of octadecylmercaptan (ODM). This sample configuration can be employed for internal reflection IRSE (using a continuous Au film), as well as to boost the detection sensitivity of IRSE through surface-enhanced infrared absorption (using discontinuous film of Au nanoislands). We study how the thickness and morphology of the Au layer in the four-phase structure affect the IRSE results for ODM by using three Au substrates: an optically thick ∼1000 A continuous film, a continuous ∼230 A thick film, and a discontinuous ∼220 A thick film of Au nanoislands. The spectral features of ODM in the last case are different form those of the first two, and are associated with surface-enhance...

Fourier Transform Infrared Spectroscopy Using Polarization Modulation and Polarization Selective Techniques for Internal and External Reflection Geometries: Investigation of Self-Assembled Octadecylmercaptan on a Thin Gold Film

By combining the polarization modulation (PM) technique with Fourier transform infrared reflection−absorption spectroscopy (FT-IRRAS), one can substantially improve the detection sensitivity and data collection efficiency. Using PM, the step of “background subtraction” can be eliminated for quantifying adsorbed species or covalently attached monolayers, and the IR spectra can be taken in situ in aqueous solutions. We demonstrate here that such a combination of PM and FT-IRRAS is possible, not only for external reflection measurements, but also for the attenuated total internal reflection (ATR) arrangement. The unique advantage of this second combination is that it couples the surface sensitivity of ATR with the experimental convenience and rapid data collection capability of polarization modulated FT-IRRAS. In the present work, we combine numerical calculations with experiments to study octadecylmercaptan (ODM) monolayers, self-assembled onto a gold-coated calcium fluoride prism. Results, including IR spectra (2800−3000 cm-1) of ODM on Au are presented for PM as well as for parallel (p) and perpendicular (s) polarization selective detection schemes and for both external reflection and ATR experimental geometries.

Studies on Self-Assembly Monolayers of Cysteine on Gold by XPS, QCM, and Electrochemical Techniques

Cysteine is a commonly used self-assembly reagent in the preparation of modified electrode and biosensors. Self-assembly of cysteine on gold has been investigated by X-ray photoelectron sepectroscopy (XPS), quartz crystal micobalance (QCM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in this article. The results of QCM and EIS revealed that the formation of saturated self-assembly monolayers of cysteine on gold required at least 30 min. The interfacial properties of the gold electrode modified with self-assembled cysteine was probed with a [Fe(CN)6]3–/4– redox couple. Contrary to the previous results obtained from the same experimental procedure with self-assembly of octadecyl mercaptan, the electrochemical behavior of the redox probe was not blocked but improved with cysteine absorbed on a gold electrode. As cysteine is electroactive, the native electrochemical properties of adsorbed cysteine are discussed as well.

Studies on Self-Assembly Monolayers of Cysteine on Gold by XPS, QCM, and Electrochemical Techniques

Cysteine is a commonly used self-assembly reagent in the preparation of modified electrode and biosensors. Self-assembly of cysteine on gold has been investigated by X-ray photoelectron sepectroscopy (XPS), quartz crystal micobalance (QCM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in this article. The results of QCM and EIS revealed that the formation of saturated self-assembly monolayers of cysteine on gold required at least 30 min. The interfacial properties of the gold electrode modified with self-assembled cysteine was probed with a [Fe(CN)6]3–/4– redox couple. Contrary to the previous results obtained from the same experimental procedure with self-assembly of octadecyl mercaptan, the electrochemical behavior of the redox probe was not blocked but improved with cysteine absorbed on a gold electrode. As cysteine is electroactive, the native electrochemical properties of adsorbed cysteine are discussed as well.

Studies of copper corrosion inhibition using electrochemical quartz crystal nanobalance and quartz crystal immittance techniques

Several copper corrosion inhibitors were tested including benzotriazole (BTA), thiourea, potassium ethyl xanthate (KEtX), octadecyl mercaptan, and Bricorr-288®. The corrosion breakdown potentials were evaluated using the electrochemical quartz crystal nanobalance (EQCN) technique, by recording linear potential scan voltammetric ( i– E) and piezogravimetric ( m– E) characteristics. Effects of single inhibitors and their mixtures on the value of the breakdown potential were investigated. Previously found synergistic effects for a mixture of BTA+KEtX and a mixture of TU+KEtX inhibitors were confirmed. The most effective among the copper corrosion inhibitors tested appeared to be Bricorr-288. The representative inhibitor films were subsequently tested using the quartz crystal immittance (QCI) technique. New equations based on experimental admittance data were derived to characterize the film acoustic resistance and the resonator parallel capacitance. On the basis of these equations, a new procedure to evaluate passive elements of the equivalent BVD electrical circuit, has been proposed. A decrease in the admittance maximum, appearing near the resonance frequency, was observed for octadecyl mercaptan and Bricorr-288 films on copper.

Mechanism for the plasma oxidation of wool fiber surfaces from XPS studies of self‐assembled monolayers

AbstractThe O2 plasma treatment of self‐assembled monolayers (SAMs) of octadecyl mercaptan on gold substrates was investigated as a model for the oxidation of wool fiber surfaces. Three controlled low‐pressure gas‐plasma treatments were employed in which the active species were (i) atomic oxygen, (ii) atomic oxygen plus vacuum UV radiation, and (iii) full plasma treatment (charged particles in addition to the above). X‐ray photoelectron spectroscopy revealed that the plasma treatments differ from each other in the extent of oxidation and etch rate with the full plasma treatment being the most aggressive plasma. The results have confirmed that the charged particles present in a full O2 plasma treatment are responsible for rapid etching of the organic surface and thus play a significant role in the oxidation mechanism due to radical formation during this process. Vacuum UV radiation also contributes to the oxidation process. Only short plasma treatment is necessary for the oxidation of the lipid layer and the SAM is a suitable model for this process. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1461–1469, 2001

Interactions of Alcohols with Hydroxyl- and Methyl-Terminated Self-Assembled Monolayer Surfaces Studied by Temperature-Programmed Desorption

The interactions of low-molecular-weight n-alcohols (n-CxH2x+1OH for x = 1−6) with 11-mercaptoundecanol (HO(CH2)11SH) or octadecyl mercaptan (CH3(CH2)17SH) adsorbed onto a nickel(111) single-crystal surface were studied by temperature-programmed desorption (TPD). Angle-dependent X-ray photoelectron spectroscopy (ADXPS) was used to characterize the adsorption of HO(CH2)11SH and CH3(CH2)17SH molecules to determine their arrangements on the nickel(111) surface. The TPD spectra for the desorption of alcohols from the hydroxyl-terminated and the methyl-terminated self-assembled monolayer surfaces at various alcohol fluences were analyzed by the threshold TPD method (TTPD) to determine their desorption energies as a function of the alcohol fluence. The TTPD-calculated alcohol desorption energies from the hydroxyl-terminated surface increased from 10 to 20 kJ mol-1 for the lowest fluences to 40−60 kJ mol-1 for the highest fluences; from the methyl-terminated surface the desorption energy increased from 10 to 25 kJ mol-1 for the lowest fluences to 45−55 kJ mol-1 for the highest fluences.

Studies of structural disorder of self-assembled thiol monolayers on gold by cyclic voltammetry and ac impedance

Self-assembly of octadecyl mercaptan on gold has been investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). CV experiments show that well-assembled thiol monolayers on gold are essentially free of pinhole defects. Support for the existence of ‘collapsed’ sites in thiol monolayers is obtained by comparing the apparent electron transfer rate constant, which is obtained from CV experiments at a film covered Au electrode, with the theoretical one, which is calculated by assuming electrons tunnel across the collapsed-site-free monolayer. The empirical relationship Z=Rs+1/[σ(jω)α] is used to describe the film coated Au in inert electrolyte and the degree of disorder of the monolayer structure is estimated from the α value. It is demonstrated that the admittance plane plot of an ideally polarizable electrode with constant phase element behavior is a circular arc which can be used to determine α. Results of EIS experiments show that α increases sharply after the initial adsorption time and approaches its final value slowly. This is attributed to the rapid adsorption step followed by a slow crystallization process in the kinetics of alkanethiol adsorption onto the Au electrode. For a well-assembled thiol monolayer on gold, α can approach 0.99, which means that the number of collapsed sites is not large and the surface of the monolayer Au electrode is rather smooth.

Structural aspects of self-assembly of thienoviologen molecular conductors on gold substrates

The adsorption of various monomethylated π-extended viologen compounds onto self-assembled layers of octadecylmercaptan (ODM) on gold was investigated with secondary ion mass spectroscopy (SIMS) and atomic force microscopy (AFM). SIMS results indicated that the monomethylated viologen 5-(4-pyridyl)-5′-[4-(N-methyl)pyridinio]-2,2′-bithiophene iodide (PT2) adsorbed much more strongly onto the ODM self-assembled layers at 50 μM adsorption concentration in ethanol, while very similar compounds were much less effective in their adsorption even at much higher adsorption concentrations. The formation of multilayers of PT2 could be observed by AFM. Some structural features of the viologens, (dipole moment and polarizability), were calculated with semi-empirical quantum chemical calculations (MOPAC/AM1). One compound, PF2, having a slightly larger molecular length, dipole moment and polarizability than PT2, did not assemble noticeably onto the surface due to its larger solubility. The large difference in efficiency of adsorption can be related to a combination of length and absence of hydrophilic groups at the free pyridine side of the monomethylated viologens.

Plasma reactions of self-assembled monolayers to model oxygen atom effects on polymers

The plasma treatment of self-assembled monolayers of octadecyl mercaptan on gold substrates has been investigated as a model for oxygen atom effects on polymers. Both O2 and H2O low pressure gas plasmas have been used. X-ray photoelectron spectroscopy has revealed that the two plasma treatments differ from each other in the extent of oxidation and etch rate with O2 being the more aggressive plasma. The results have confirmed that the plasma modification of organic surfaces involves a balance between surface oxidation and surface etching. The well-defined structure of the monolayer enables quantitation of these atom-substrate reactions. © 1998 John Wiley & Sons, Ltd.

Plasma reactions of self‐assembled monolayers to model oxygen atom effects on polymers

The plasma treatment of self-assembled monolayers of octadecyl mercaptan on gold substrates has been investigated as a model for oxygen atom effects on polymers. Both O2 and H2O low pressure gas plasmas have been used. X-ray photoelectron spectroscopy has revealed that the two plasma treatments differ from each other in the extent of oxidation and etch rate with O2 being the more aggressive plasma. The results have confirmed that the plasma modification of organic surfaces involves a balance between surface oxidation and surface etching. The well-defined structure of the monolayer enables quantitation of these atom-substrate reactions. © 1998 John Wiley & Sons, Ltd.

A Desalting Approach for MALDI-MS Using On-Probe Hydrophobic Self-Assembled Monolayers

One of the problems encountered in preparing samples for matrix-assisted laser desorption/ionization (MALDI) analysis is the presence of nonvolatile salts in the sample. This difficulty is often exacerbated by the necessity to prepare the sample in the appropriate sample-to-matrix ratio. This paper reports a probe surface derivatization method that greatly simplifies this sample preparation process. By constructing self-assembled monolayers of octadecyl mercaptan (C18) on the MALDI probe surface, we were able to generate a surface capable of reversibly binding polypeptides via hydrophobic interactions, which in turn, permits the analyte to be easily concentrated and desalted directly on the probe tip.

Cytomimetic Biomaterials. 2. In-Situ Polymerization of Phospholipids on a Polymer Surface

A stabilized, phosphatidylcholine-containing polymeric surface was produced by in-situ polymerization on an amphiphilic polymer surface. The phospholipid monomer, 1-palmitoyl-2-[12-(acryloyloxy)dodecanoyl]-sn-gycero-3-phosphorylcholine, was prepared as unilamellar vesicles and fused onto a terpolymer consisting of the monomers 2-(methylthio)ethyl methacrylate, 2-hydroxyethyl acrylate, and 3-acryloyl-3-oxapropyl-3-(N,N-dioctadecylcarbamoyl)propionate. Free-radical polymerization was carried out in aqueous solution at 70 °C using the water-soluble initiator, 2,2‘-azobis(2-methylpropionamidine) dihydrochloride. The supported monolayer displayed advancing and receding water contact angles of 58° and 31°, respectively. Angle-dependent electron spectroscopy for chemical analysis (ESCA) results confirmed the presence of phosphorus and nitrogen and was consistent with theoretical predictions for a close-packed monolayer. Ellipsometry measurements indicated a film thickness of 134 Å. In the absence of network formation, polymeric films demonstrated acceptable stability under static conditions in water. For comparative analysis, the phospholipid was also fused and polymerized onto a self-assembled monolayer of octadecyl mercaptan (ODT) bound to gold. ESCA data were consistent with a close packed monolayer and ellipsometry revealed a film thickness of 66 Å. Nonetheless, contact angle measurements demonstrated that the polymerized lipid monolayer when supported on an ODT surface exhibited a higher level of instability over time than that supported by the amphiphilic terpolymer.

X-ray photoelectron spectroscopy of partial and stamped thiol-based self-assembled monolayers

X-ray photoelectron spectroscopy was used to explore the local environment of a perfluorinated thiol derivative incorporated into an alkanethiol matrix. The alkanethiol octadecylmercaptan (ODT) was formed via a printing procedure and samples taken at various stages of stamp depletion were investigated. Compared with the spectra obtained from a monolayer of the perfluorinated material adsorbed directly from solution, one can see distinct differences in the shape of the F 1s peak. We present possible interpretations of this behaviour from a molecular perspective.