Electrical properties of end-group functionalised Self-Assembled Monolayers

Collet, J.; Bonnier, M.; Bouloussa, Othman; Rondelez, F.; Vuillaume, D.

doi:10.1016/s0167-9317(97)00029-4

Cited by 11 publications

(8 citation statements)

References 5 publications

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“…Monolayers made of fatty acids, n -alkyltrichlorosilanes, or n -alkylthiols were then shown to be electronic insulators. A contribution from electron tunneling to the measured conductivity, σ, at room temperature was ruled out, as there was no dependence of σ on SAM thickness. − The measured conductivities for n -alkyltrichlorosilane and n -alkylthiol SAMs were instead attributed to the intrinsic electrical properties of the organic monolayers, given that the conductivities are in the same range as those of bulk poly(ethylene) (2 × 10 -16 Ω -1 cm -1 )…”

Section: Introductionmentioning

confidence: 99%

Insulating Properties of Self-Assembled Monolayers Monitored by Impedance Spectroscopy

2000

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The ionic insulating properties of n-alkylthiol self-assembled monolayers (SAMs) and a related fluorinated SAM are characterized by electrochemical ac impedance spectroscopy. CH3(CH2) n S/Au (n = 7−15) SAMs prepared via prolonged incubation in a thiol solution obey the Helmholtz ideal capacitor model and thus are virtually defect-free. The electrochemical properties of SAM-coated electrodes are compared with those of a bare gold electrode. The phase angle at an ion-diffusion-related frequency (1 Hz) is ≥ 88° and is independent of the electrolyte concentration. The thiol chains act as a dielectric material whose impedance (modulus) is 105 Ω cm2 at 1 Hz. Both the phase angle and the complex dielectric constant in the low-frequency region are good indicators of the film's ability to act as an ionic insulator.

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Section: Introductionmentioning

confidence: 99%

Insulating Properties of Self-Assembled Monolayers Monitored by Impedance Spectroscopy

2000

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“…Pioneered by Zisman in the 1940s, 1 self-assembled monolayers (SAMs) have found applications in many important fields such as wettability, 2 corrosion protection, 3 chromatography, 4 and molecular electronics. 5 Alkylsiloxane SAMs 6 and alkanethiol SAMs 7 have emerged as the two types of most widely studied SAMs. Both SAMs share similarity in the close packing of hydrocarbon chains on surfaces.…”

Section: Introductionmentioning

confidence: 99%

Photoreactivity of Alkylsiloxane Self-Assembled Monolayers on Silicon Oxide Surfaces

Wynn

Dudek

et al. 2001

Langmuir

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We have combined contact angle measurements, Fourier transform infrared spectroscopy (FT-IR), and atomic force microscopy (AFM) to investigate the UV photoreactivity of octadecylsiloxane (ODS) SAMs (self-assembled monolayers) in air. Contact angle measurements present evidence that ozone is not the active agent in alkylsiloxane SAM degradation under UV illumination in air. A combination of UV and oxygen is necessary for monolayer degradation to proceed. AFM measurements on submonolayer coverage SAMs provide direct evidence of the photodegradation of ODS SAMs and reveal the role of defects in the degradation process. FT-IR and AFM results suggest that the hydrocarbon chain is the reactive site of the monolayers. A microscopic mechanism of the photoreactivity involving hydrogen abstraction is suggested based on the mechanism of gas-phase oxidation of alkanes. Our results have implications in clarifying the contribution from the reactivity of alkyl chains during the photomodification of SAMs. This clarification may provide insight into optimization of the SAM photopatterning processes.

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“…Functionalizing such dense silane SAMs after their grafting does not have a significant effect on their good insulating properties [113]. Long chains of alkyl silanes (18-20 carbon atoms) form SAMs from the liquid phase which are better ordered and denser, thus more effectively screening the influence of the substrate when compared to shorter hydrocarbon chains [57,83,114].…”

Section: Chain Length Order and Defectsmentioning

confidence: 99%

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

et al. 2006

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The control and modification of surface state is a major challenge in bioanalytical sciences, and in particular in electrokinetic separation methods, due to the importance of electroosmosis. This topic has gained recently a renewed interest, associated with the development of "lab-on-chips" systems that extend the range of materials in which separation channels are fabricated. The surface science community has developed through the years a large toolbox of characterization tools and surface modification protocols, which is not yet fully exploited in the bioanalytical world. In this paper, we try and present an overview of these tools, in order to stimulate new ideas for improved and more controlled surface treatment strategies for separations in capillaries and microchannels. We briefly describe some physical and chemical aspects of electroosmosis (global and spatially resolved), streaming current, and streaming potential. We also review the main strategies for surface coating, and compare the advantages of physisorption, well-organized thin self-assembled monolayers, or conversely thick polymer "brushes". Examples of existing applications to electrophoresis in microchannel are also given.

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Electrical properties of end-group functionalised Self-Assembled Monolayers

Cited by 11 publications

References 5 publications

Insulating Properties of Self-Assembled Monolayers Monitored by Impedance Spectroscopy

Insulating Properties of Self-Assembled Monolayers Monitored by Impedance Spectroscopy

Photoreactivity of Alkylsiloxane Self-Assembled Monolayers on Silicon Oxide Surfaces

Surface treatment and characterization: Perspectives to electrophoresis and lab‐on‐chips

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