Preferential adsorption of solid monolayers of hydrocarbons over fluorocarbons at the solid/liquid interface

Parker, Julia; Clarke, Stuart M.; Perdigón, Ana C.

doi:10.1016/j.susc.2007.04.182

Cited by 9 publications

(9 citation statements)

References 11 publications

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“…This binary immiscible system is comprised of solvents that represent end-of-the-spectrum polarities, possess a large interfacial surface tension, and lead to selective wetting as the nonpolar fluoroalkane deposits a self-adsorbed solid monolayer on the surface of the hydrophobic substrate (41,42). Vigorous mixing of this nonpolar perfluorinated fluid with water leads to an emulsion of droplets stabilized by a significant negative charge (43), trapping nanofibers at the liquid-liquid interface, thus allowing droplet coalescence to deposit a film.…”

Section: Resultsmentioning

confidence: 99%

Versatile solution for growing thin films of conducting polymers

D’Arcy

Tran²,

Tung³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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The method employed for depositing nanostructures of conducting polymers dictates potential uses in a variety of applications such as organic solar cells, light-emitting diodes, electrochromics, and sensors. A simple and scalable film fabrication technique that allows reproducible control of thickness, and morphological homogeneity at the nanoscale, is an attractive option for industrial applications. Here we demonstrate that under the proper conditions of volume, doping, and polymer concentration, films consisting of monolayers of conducting polymer nanofibers such as polyaniline, polythiophene, and poly(3-hexylthiophene) can be produced in a matter of seconds. A thermodynamically driven solution-based process leads to the growth of transparent thin films of interfacially adsorbed nanofibers. High quality transparent thin films are deposited at ambient conditions on virtually any substrate. This inexpensive process uses solutions that are recyclable and affords a new technique in the field of conducting polymers for coating large substrate areas.Marangoni | surface tension | thin film technology | organic electronics C onducting polymers hold promise as flexible, inexpensive materials for use in electronic applications including solar cells, light-emitting diodes, and chemiresistor-type sensors (1-3). Whereas traditional nonconjugated polymers are often solutionprocessable, many organic conducting polymers have been notoriously difficult to process into films. Thin films of conducting polymers offer a large ratio of charge carriers to volume of active layer (4) and can achieve high field-effect mobilities as a result of low-dimensional transport (5). Therefore a simple, scalable, cost-effective deposition technique for conducting polymers that produces a uniform thin film morphology reproducibly is needed.Film-forming methods for conducting polymers on the basis of solution processing, electrochemistry, and thermal annealing have been reported in the literature but suffer from a variety of problems. The conducting polymers polyaniline (PANi), polythiophene, and their derivatives such as poly(3-hexylthiophene) (P3HT) are commonly processed into nanoscale thin films via spin coating (1, 5-7) for applications in organic photovoltaics, thin film transistors, and electrochromic devices (8-12). However, spin coating is a technique that suffers from a low material utilization yield and is therefore not cost-effective (11), a fact that hinders its potential for scale-up. Another well known deposition strategy is the electrochemical growth of conducting polymer thin films via galvanostatic, potentiostatic, or voltammetric routes (9,(13)(14)(15)). An inherent limitation of using electricity for thin film deposition is the dual role played by the electrode/substrate, which excludes the possibility of film deposition on a nonconducting substrate. This problem also applies to electrospraying because it requires a high voltage across electrodes (11). Other solution-based methods also present challenges; for example, the Lang...

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Section: Resultsmentioning

confidence: 99%

Versatile solution for growing thin films of conducting polymers

D’Arcy

Tran²,

Tung³

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

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“…The essentially equivalent adsorption of these species is not unsurprising, given that preferential adsorption is usually a function of increasing alkyl chain length. 21,22,28,[41][42][43][44][45][46][47] Here both species have equal alkyl chain lengths and so are expected to adsorb equally strongly on this surface.…”

Section: ' Results and Discussionmentioning

confidence: 99%

“…The composition of the pronounced maximum in melting point somewhere in the region of 0.5−0.6 mol fraction suggests that the surface composition is essentially that of the bulk and there is minimal preferential adsorption which can be represented by a small preferential adsorption equilibrium constant of no more than 1.15. The essentially equivalent adsorption of these species is not unsurprising, given that preferential adsorption is usually a function of increasing alkyl chain length. ,,,− Here both species have equal alkyl chain lengths and so are expected to adsorb equally strongly on this surface.…”

Section: Resultsmentioning

confidence: 99%

Bulk and Adsorbed Monolayer Phase Behavior of Binary Mixtures of Undecanoic Acid and Undecylamine: Catanionic Monolayers

et al. 2011

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Differential scanning calorimetry (DSC) and X-ray powder diffraction (PXRD) have been used to determine the phase behavior of the binary mixtures of undecanoic acid (A) and undecylamine (B) in the bulk. In addition, we report DSC data that indicates very similar behavior for the solid monolayers of these materials adsorbed on the surface of graphite. The two species are found to form a series of stoichiometric complexes of the type AB, A 2 B, and A 3 B on the acid rich side of the phase diagram. Interestingly, no similar series of complexes is evident on the amine rich side. As a result of this complexation, the solid monolayers of the binary mixtures exhibit a very pronounced enhancement in stability relative to the pure adsorbates.

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“…They are observed to form close-packed solid monolayers on graphite, though exhibit a comparatively low adsorption energy, and hence are displaced from the surface by the stronger binding hydrocarbon alkanes. 27 This low adsorption energy is symptomatic of the low polarizability of fluorine and, hence, the weak van der Waals (vdW) interactions present between the chains. This relative weakness of the intermolecular vdW interactions is key to crystal design, as it would be hoped to reduce the energetic cost in deviating from close-packing when forming a porous system.…”

Section: Introductionmentioning

confidence: 99%

“…Due to the large steric bulk of the fluorine atoms these chains adopt a helical structure rather than the characteristic trans -chain configuration of alkanes. They are observed to form close-packed solid monolayers on graphite, though exhibit a comparatively low adsorption energy, and hence are displaced from the surface by the stronger binding hydrocarbon alkanes . This low adsorption energy is symptomatic of the low polarizability of fluorine and, hence, the weak van der Waals (vdW) interactions present between the chains.…”

Section: Introductionmentioning

confidence: 99%

Halogen Bonding in Bicomponent Monolayers: Self-Assembly of a Homologous Series of Iodinated Perfluoroalkanes with Bipyridine

et al. 2021

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A homologous series of halogen bonding monolayers based on terminally iodinated perfluoroalkanes and 4,4′-bipyridine have been observed on a graphitic surface and noninvasively probed using powder X-ray diffraction. An excellent agreement is observed between the X-ray structures and density functional theory calculations with dispersion force corrections. Theoretical analysis of the binding energies of the structures indicate that these halogen bonds are strong (25 kJ mol –1 ), indicating that the layers are highly stable. The monolayer structures are found to be distinct from any plane of the corresponding bulk structures, with limited evidence of partitioning of hydrocarbon and perfluoro tectons. The interchain interactions are found to be slightly stronger than those in related aromatic systems, with important implications for 2D crystal engineering.

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Preferential adsorption of solid monolayers of hydrocarbons over fluorocarbons at the solid/liquid interface

Cited by 9 publications

References 11 publications

Versatile solution for growing thin films of conducting polymers

Versatile solution for growing thin films of conducting polymers

Bulk and Adsorbed Monolayer Phase Behavior of Binary Mixtures of Undecanoic Acid and Undecylamine: Catanionic Monolayers

Halogen Bonding in Bicomponent Monolayers: Self-Assembly of a Homologous Series of Iodinated Perfluoroalkanes with Bipyridine

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