Octadecylamine Monolayer Research Articles

Penetration of DNA into Mixed Monolayers of 1,3-Bis(salicylideneamino)propanechromium(III) Perchlorate and Octadecylamine at an Air/Water Interface

The dynamics of surface pressure (π) of DNA adsorbed onto mixed monolayers of octadecylamine (ODA) with trans-diaquo-1,3-bis(salicylideneamino)propanechromium(III) perchlorate, [Cr(salprn)(H2O)2]ClO4, has been measured. The adsorption of DNA takes place only when a lower concentration limit of [Cr(salprn)(H2O)2]ClO4 is present in the spread film, indicating synergism due to the possible interaction of DNA with [Cr(salprn)(H2O)2]ClO4 after interacting with loosely or moderately packed ODA molecules through hydrogen bonds. The results point to an enhanced DNA adsorption by relatively dilute ODA monolayer densities and a decline of adsorption with dense lipid monolayer.

Surface Characterization of Octadecylamine Films Prepared by Langmuir−Blodgett and Vacuum Deposition Methods by Dynamic Contact Angle Measurements

The behavior of octadecylamine (ODA) monolayers on various subphases is investigated. The monolayer is then transferred to a hydrophilic glass surface to prepare a LB film of one monolayer. The uniformity, stability, and molecular orientation of the LB films were studied by the measurement of dynamic contact angle and compared with characteristics of vacuum-deposited films. The results show that the ODA monolayer is especially stable on alkaline solution. The LB film transferred from the alkaline solution is stable and uniform in wettability. The advancing and receding contact angles of water on one layer of ODA film are about 113° and 62°, respectively. These values are the same as those on a vacuum-deposited ODA film of equivalent thickness. The growth of ODA on a glass surface in a vacuum deposition is thus found to follow a mode of layer growth. The orientation and arrangement of molecules on the LB films are affected by the surface pressure and transferring rate during the transferring procedure. When the transfer is proceeded at low surface pressure and high transferring rate, the ODA molecules are irregularly packed without uniform orientation. However, during the analysis of dynamic contact angle (DCA), the movement of the three-phase contact line has an effect to rearrange the irregularly packed molecules of ODA on the LB films and the surface becomes more and more uniform with the analytic cycles of the DCA. By comparing between the LB films of ODA and stearic acid, the advancing contact angles are identical for both, but the very small value of receding contact angle on stearic acid reflects the exposure of the hydrophilic glass on the stearic acid film. The existence of holes in the stearic acid monolayer is thus proved by the measurement of wettability.

Intercolloidal Particle Monolayer Transfer in Mixed Metal Colloids

In this paper, we provide the first evidence that suggests transfer of molecules in self-assembled monolayers between colloidal metal particles. This was studied by capping silver/gold colloidal particles with a bifunctional molecule, 4-carboxythiophenol, and then mixing to the capped sol, uncapped colloidal particles of gold/silver. The transfer of the capping molecule to the bare metal particle surface leads to carboxylic acid derivatization of the uncapped sol as well. The resulting carboxylic acid derivatization of the uncapped clusters by intercolloidal particle monolayer transfer was determined by electrostatic complexation of the clusters in the mixed hydrosol at the air-water interface with a Langmuir monolayer of octadecylamine, the carboxylic acid groups playing the role of sticky tracers. Optical absorption spectroscopy and energy dispersive analysis of X-rays measurements of Langmuir-Blodgett films formed from subphases of sols of capped silver/gold mixed with uncapped gold/silver revealed the presence of both silver and gold particles in the film thereby pointing to the transfer of molecules between the colloidal particles. Possible mechanisms for the intercolloidal particle monolayer transfer observed are briefly discussed.

Studies on mixed europium complex/octadecylamine monolayers with various molar ratios on an aqueous solution subphase surface

The structures and properties of mixed monolayers of a luminous rare earth complex Eu(TTA) 4CTA with octadecylamine (ODA) on an Eu(TTA) 4 − aqueous solution subphase surface have been studied. The plateaus, appearing on the π- A isotherms of Eu(TTA) 4CTA, ODA and Eu(TTA) 4CTA/ODA (1:1, 1:2, 1:4) monolayers at 14 mN/m, correspond to a structural change process of the monolayers. The head groups closely packed monolayers change to long tails closely packed monolayers during this process. The observation of transmission electron microscopy (TEM), electron diffraction (ED) and fluorescence microscopy (FM) indicate that crystals of the complex are formed at the plateau for Eu(TTA) 4CTA, Eu(TTA) 4CTA/ODA (1:1, 1:2) mixed monolayers, and no crystal of the complex is formed at the plateau for Eu(TTA) 4CTA/ODA (1:4) and ODA monolayers. The UV–vis spectra and fluorescence spectra of mixed LB films show that the different structures greatly affect the film properties.

Adsorption Behavior of Methyl Orange on the Monolayer and Langmuir–Blodgett Films of Octadecylamine

Abstract The monolayer properties of octadecylamine (ODA) on both distilled water and aqueous Methyl Orange (MO) solution were studied from the measurements of surface pressure–area (π–A) isotherms. From the π–A isotherms at various pHs, hydroxide ions, and MO anions in the subphase were confirmed to interact competitively with the ODA monolayer. Furthermore, Langmuir–Blodgett (LB) film of ODA was fabricated from the surface of an alkaline subphase, and the adsorption characteristics of the ODA LB film were investigated by using MO as an adsorbate. As a result, the ODA LB film exhibited specific adsorbability for the MO anion, similar to that of the LB film of long-chain quaternary alkylammonium salt, but the adsorption rate of the MO on the ODA LB film was slower than that on the LB film of long-chain quaternary alkylammonium salt. In addition, adsorbability of the ODA LB film showed pH dependence.

Electrostatic Complexation of Carboxylic Acid Derivatized Silver Colloidal Particles with Fatty Amine Langmuir Monolayers. Role of Neutral Spacer Molecules in the Monolayer

In a series of papers we have investigated the electrostatic complexation of carboxylic acid-derivatized metal colloidal particles with charged fatty amine Langmuir monolayers and the formation of Langmuir Blodgett (LB ) films of the colloidal particles. The role of the subphase pH in controlling the cluster density at the air-water interface and in the builtup films was addressed. In this paper we advance our study to include the effects of an uncharged spacer molecule, octadecanol, on the colloidal particle complexation at the air-water interface in mixed Langmuir monolayers of octadecanol and octadecyl amine. The surface density of the charged amine molecules was controlled by varying the molar concentrations of amine and alcohol molecules in the Langmuir monolayer and the time dependence of the complexation followed using π-A isotherms, quartz crystal microgravimetry and UV-vis spectroscopy measurements. The equilibrium cluster density at the air-water interface and consequently in the LB films was enhanced as the fraction of amine molecules in the Langmuir monolayer increased. The complexation of the clusters at the air-water interface is slow, taking ∼ 15 h to reach equilibrium densities. Cluster density-dependent shifts in the surface plasmon resonance were observed in builtup LB films and have been explained in terms of an effective medium theory. Ellipsometry studies of the builtup multilayer films indicate that fairly uniform cluster density films can be deposited by the LB technique. The results presented in this paper are consistent with an electrostatic interaction-mediated process for the complexation of carboxylic acid-derivatized colloidal particles with fatty amine Langmuir monolayers.

Interaction of Poly(.alpha.,.beta.-aspartate) with Octadecylamine Monolayers: Adsorption Behavior and Effects on CaCO3 Crystallization

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTInteraction of Poly(.alpha.,.beta.-aspartate) with Octadecylamine Monolayers: Adsorption Behavior and Effects on CaCO3 CrystallizationJon M. Didymus, Stephen Mann, William J. Benton, and Ian R. CollinsCite this: Langmuir 1995, 11, 8, 3130–3136Publication Date (Print):August 1, 1995Publication History Published online1 May 2002Published inissue 1 August 1995https://doi.org/10.1021/la00008a044RIGHTS & PERMISSIONSArticle Views299Altmetric-Citations37LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (2 MB) Get e-Alerts Get e-Alerts

Adsorption of Antibodies to a Langmuir Layer of Octadecylamine and the Interaction with Antigen

The adsorption of antibodies against C-reactive protein onto a monolayer of octadecylamine has been studied at the air/water interface by following the change in area of the monolayer at different surface pressures. Binding of antibodies was dependent both on the packing of the film and on the antibody concentration in the aqueous subphase. An equilibrium was reached above an antibody concentration of 2 mg/dm3. The monolayer was stabilized by the antibodies. The mixed monolayer could be transferred onto a quartz crystal microbalance. However, the high nonspecific binding of bovine serum albumin makes it difficult to determine the interaction of the antigen with the octadecylamine/antibody layer.

Maxwell displacement current across single monolayers

An electrical technique that allows reorganization of single monolayers to be probed by measuring the Maxwell displacement current flowing across monolayers is described. The Maxwell displacement current is generated from single monolayers with the application of an external stimulus ( e.g. pressure, light or heat) in the absence of an external electric field. The current across octadecylamine monolayers with thermal stimulation is given as an example of the Maxwell displacement currents.

Quantitative Static Secondary Ion Mass Spectrometry of pH Effects on Octadecylamine Monolayer Langmuir-Blodgett Films

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTQuantitative Static Secondary Ion Mass Spectrometry of pH Effects on Octadecylamine Monolayer Langmuir-Blodgett FilmsJian-Xin. Li and Joseph A. GardellaCite this: Anal. Chem. 1994, 66, 7, 1032–1037Publication Date (Print):April 1, 1994Publication History Published online1 May 2002Published inissue 1 April 1994https://doi.org/10.1021/ac00079a018RIGHTS & PERMISSIONSArticle Views87Altmetric-Citations13LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (622 KB) Get e-Alerts Get e-Alerts

Template‐directed nucleation and growth of inorganic materials

A new way to tailor the crystal chemistry of inorganic solids involves molecular recongnition between two‐dimensional organic templates and embryonic inorganic aggregates. Langmuir monolayers adopted as model surfaces offer opportunities for molecular engineering of the template. The Figure shows one example of oriented nucleation of vaterite under octadecylamine monolayers. magnified image

Structural and stereochemical relationships between Langmuir monolayers and calcium carbonate nucleation

The structural and stereochemical factors involved in the oriented nucleation of CaCO3 under compressed Langmuir monolayers have been studied by optical and electron microscopy, and X-ray and electron diffraction. The effect of headgroup charge, stereochemistry and changes in supersaturation have been investigated. At total (Ca)=9 mM, monolayers with carboxylate headgroups induce the oriented nucleation of calcite with the (11.0) axis perpendicular to the organic surface. At (Ca)=4.5 mM, oriented vaterite with the (00.1) axis normal to the monolayer, is deposited. The common features of these interactions are: Ca accumulation at the stearate headgroups, geometric matching of lattice distances (calcite only) and stereochemical correspondence between carboxylate and carbonate groups at the monolayer/crystal interface. In contrast, nucleation under positively charged octadecylamine monolayers was independent of (Ca) and gave vaterite aligned either along the (00.1) or (11.0) crystallographic axes. Although Ca binding is absent on these films, there is the possibility of stereochemical matching between bidentate binding of bicarbonate and the corresponding anions in the (00.1) and (11.0) crystal surfaces. Crystals (calcite and vaterite) grown under liquid-phase stearate monolayers were of increased size and uniformity in particle size distribution compared with those nucleated under fully compressed films. CaCO3 crystallization under octadecanol monolayers was inhibited and crystals grown in the presence of cholesterol films were the same as in the control experiments.

Oriented crystallization of CaCo3under compressed monolayers. Part 2.—Morphology, structure and growth of immature crystals

Transmission electron microscopy and electron diffraction have been used to determine the structure, orientation and morphology of CaCO3 crystals at the early stages of growth under compressed Langmuir monolayers of stearic acid [CH3(CH2)16CO2H] and octadecylamine [CH3(CH2)17NH+3]. At [Ca]≈ 9 mmol dm–3, elongated plate-like calcite single crystals of narrow particle size distribution were nucleated under fully compressed stearate monolayers. The crystals were elongated along the c axis and oriented with a {1text-decoration:overline10} face parallel to the monolayer/solution interface. Subsequent development of the crystals resulted in rhombohedral outgrowth into the bulk solution. Calcite crystals nucleated under partially compressed monolayers showed the same crystal chemical properties but had a more uniform size population. Nucleation under octadecylamine monolayers resulted in disc-shaped vaterite single crystals of narrow particle size distribution. Two types of disc were observed: (a) circular/hexagonal crystals oriented with their c axis perpendicular to the monolayer, and (b) oval-shaped crystals oriented with their a axis perpendicular to the monolayer. Changes in monolayer surface pressure did not influence these properties. The preferred orientation of calcite can be rationalized in terms of geometric and stereochemical matching between the carboxylate headgroups and the ions in the {1text-decoration:overline10} crystal face. There is no geometric match for vaterite but a stereochemical relationship exists on stearate monolayers with respect to the (00.1) face. For octadecylamine monolayers, bidentate binding of HCO–3 may be important in determining the preferential orientation of nuclei formed at the organic surface.

Three-phase contact line movement in systems with and without surfactant

The dependence of the receding contact angle on the speed of movement of the three-phase contact (tpc) after rupture of the thin liquid film during bubble/solid interaction has been investigated. The motion of the type on a quartz surface covered with an octadecylamine monolayer is described using molecular and hydrodynamic theories. For a surfactant-containing system (quartz/dodecylamine solution/air) it was found that the experimental results cannot be described completely by these theories. These discrepancies are thought to be due to surfactant transfer from the liquid/gas to the solid/gas interface during receding tpc motion, resulting in a decrease of the surfactant at the liquid/gas interface.

Interaction of octadecylamine monolayers with phosphate counterions

By means of neutron activation analysis of octadecylamine multilayers deposited from phosphate subsolutions at different pH and salt concentrations, the interaction of the monolayers with the phosphate anions is studied. It is found that between pH 4.5 and 9.5 it is mainly the divalent form HPO 4 2− which interacts with the octadecylammonium cations. The stability constant of the octadecylammonium hydrogenphosphate is estimated by applying the Scatchard-Hildebrand theory to evaluate the activity coefficients of the monolayer components.

A Study of Monolayer Penetration by the Radiotracer Method

Abstract The surface pressure - area isotherms of monolayers of cholesterol, hexadecyl alcohol and octadecyl amine on sodium alkyl sulfate solutions and the surface excess of alkyl sulfate have been measured by the film balance and the radiotracer methods respectively. These measurements were carried out with (1) the monolayers spread on the alkyl sulfate solutions, (2) those below which the detergent solutions were injected, and (3) those formed by the spreading of the insoluble speciesdetergent mixtures on water. All the surface pressure - area curves showed remarkable expansions; the results were essentially the same as those observed by Schulman et al. and by others. On the other hand, the surface excess of alkyl sulfates showed no appreciable increase in the case of cholesterol and hexadecyl alcohol, and it was too low to form a stoichiometric complex between the insoluble species and the alkyl sulfate; only in the presence of the octadecyl amine did it increase to an amount sufficient to form the 1 : 1 stoichiometric salt. Thus it has been concluded that the expansion of the surface pressure - area curve can not be an indication of the stoichiometric complex formation. It has been pointed out that the surface pressure of the detergent solution increases with the compression, even in the absence of a monolayer; this is the main cause for the expansion of the surface pressure - area curve of the penetrated monolayer. The phenomenon of monolayer penetration has been explained in terms of the formation of the adsorbed layer of alkyl sulfate, and the reactivity for penetration has been related to the surface activity of detergents.

Studies on the Interaction of Surface Films with Solute in Solution. IV. Effect of Congo Red Dissolved in Aqueous Substrate upon the Monolayers of Octadecylamine, Cetyl Alcohol, Ethyl n-Hexadecyl Ether, Ethyl Stearate and Cholesterol

Abstract Effect of dissolved Congo red upon the monolayers of octadecylamine, cetyl alcohol, ethyl n-hexadecyl ether, ethyl stearate and cholesterol spread on the substrate containing the dye has been studied, under varying pH of the solution. It has been observed generally that all monolayers expanded when they were spread on aqueous solution, the pH of which was in such a region that the molecules of dye were almost in zwitterion form. Dipolar and van der Waals’ attraction were tentatively postulated to explain the nature of the cohesive force by which the molecules of dye were bond together so that the colloidal aggregates were formed in the solution. The expansion of the monolayer can be accounted for by the binding of the aggregate to film materials. This explanation could successfully be applied to the films of such nonionic substance as cetyl alcohol, ethyl n-hexadecyl ether and ethyl stearate. The largest expansion of the monolayer of octadecylamine was observed when the substrate containing dye showed acidity so that the molecules of dye were partly of negative charge while those of octadecylamine were of positive charge. In this case we had better take account of the possibility of ion-ion attraction between octadecylamine and dye, in addition to the forces which appeared in the cases of nonionic substances.

Studies on the Interaction of Surface Films with Solute in Solution. III. Effect of Dissolved Dyes upon the Monolayer of Octadecylamine

Abstract The interaction between octadecylamine in monolayer and various dyes in aqueous substrate under varying pH was studied. Such a basic dye as chrysodine or crystal violet remarkably expanded the monolayer when pH of the solution was in a certain range on alkaline side. This has been attributed to the interactions between the molecules of dye themselves and that between dye and octadecylamine. Thus, it is mainly dipolar and van der Waals’ attraction, which was considered to be overshadowed by ionic repulsion when substrate pH was in the other region. Additional possibility of ion-dipole attraction due to the remaining charge of the monolayer was discussed in connection with the ionizations of octadecylamine and basic dyes. In contrast with this, the monolayer expanded remarkably when it was spread on an acidic solution of acid dye. The behavior could be accounted for by the sum of ionic, dipolar and van der Waals’ attraction. The possibility of the formation of colloidal aggregate of dye with which octadecylamine interacts has been discussed, in connection with the effect of metal ion in the substrate upon the monolayer of stearic acid.

On the Nature of Built-Up Film. III. Effect of Dissolved Anion on Mono- and Multilayers of Octadecylamine

Abstract Attempts were made to transfer the monolayers of octadecylamine on distilled water both onto the metal surface and onto the optical gauge of barium stearate. They did not adhere to the former surface, while with the latter it was shown that the homogeneous film was obtained when the substrate pH. and the piston pressure were favorable for preventing the film from aggregating. Effects of organic anions upon the monoand multilayers of amine were investigated. The increase of the distance between the ionic groups of dicarboxylic acids caused the corresponding expansion and change in thickness of amine monolayer spread on the solution containing these anions. The solution of sodium alginate caused a somewhat large expansion and gave a remarkable rigidity towards the amine monolayer spread on it. The built-up film of amine transferred from the substrate of various organic acids showed a variety of resistance for wettability when treated with aqueous sodium alginate solution. It was found that the resistance for wetting increased with the increasing complexity of the two-dimensional network formed in the film prior to the treatment. These results were discussed with regard to the easiness of overturning.

The spreading of liquids on low-energy surfaces. V. Perfluorodecanoic acid monolayers

The wettability of more than 90 pure liquids on oriented close-packed monolayers of perfluorodecanoic acid adsorbed on platinum, copper, brass, and glass has been studied. Comparison with results reported earlier for solid polyethylene, oriented monolayers of octadecylamine, and solid polytetrafluoroethylene shows that oriented, close-packed monolayers of perfluorodecanoic acid are the most nonwettable surfaces ever found and that for most liquids in contact with these surfaces the contact angle (θ) decreases in the order θ CF 3 > θ CF 2 > θ CH 3 > θ CH 2. Values of the work of adhesion, the initial and final spreading coefficients, and the free energy decrease on immersion, f SL , were computed from contact angle measurements and surface tensions using the assumption justified by experiment that f SV ∘ = 0. From the values of f SL , it has been possible to estimate the free surface energy of the surfaces prepared from films of perfluorodecanoic acid. Structural differences determining the wetting properties of liquids are presented, and the effect of increase in surface tension of higher members in a homologous series is discussed. Observed modifications of the wetting properties of high-energy solids by adsorption of a single monolayer, demonstrate beyond doubt the short-range nature of the forces involved in wetting. In view of the remarkable resistance to wetting shown by surfaces of close-packed perfluoromethyl groups, surface-active compounds with —CF 3 groups and hydrophilic groups at opposite ends of the molecule should have unusual and valuable properties, and they deserve to be treated as a special class of surface-active compounds.