Mixed Self-Assembled Monolayers of Alkanethiolates on Ultrasmooth Gold Do Not Exhibit Contact-Angle Hysteresis

Gupta, Pooja; Ulman, Abraham; Fanfan, Stephanie; Korniakov, Alexander; Loos, Katja

doi:10.1021/ja044623e

Cited by 85 publications

(66 citation statements)

References 23 publications

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“…However, even when considering the error bars, a marked hysteresis still remains on TSG. This result does not agree with the data reported by Ulman and coworkers 58. These authors used dodecane-1-thiol (DoDT) and 11-mercaptoundecan-1-ol (MUO) instead of MHDA and ODT, respectively, and employed a different way to measure the contact angle.…”

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confidence: 59%

Optimized Model Surfaces for Advanced Atomic Force Microscopy Studies of Surface Nanobubbles

2016

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The formation of self-assembled monolayers (SAMs) of binary mixtures of 16-mercaptohexadecanoic acid (MHDA) and 1-octadecanethiol (ODT) on ultraflat template-stripped gold (TSG) surfaces was systematically investigated to clarify the assembly behavior, composition, and degree of possible phase segregation in light of atomic force microscopy (AFM) studies of surface nanobubbles on these substrates. The data for SAMs on TSG were compared to those obtained by adsorption on rough evaporated gold, as reported in a previous study. Quartz crystal microbalance and surface plasmon resonance data acquired in situ on TSG indicate that similar to SAM formation on conventional evaporated gold substrates ODT and MHDA form monolayers and bilayers, respectively. The second layer on MHDA, whose formation is attributed to hydrogen bonding, can be easily removed by adequate rinsing with water. The favorable agreement of the grazing incidence reflection Fourier transform infrared (GIR FTIR) spectroscopy and contact angle data analyzed with the Israelachvili-Gee model suggests that the binary SAMs do not segregate laterally. This conclusion is fully validated by high-resolution friction force AFM observations down to a length scale of 8-10 nm, which is much smaller than the typical observed surface nanobubble radii. Finally, correspondingly functionalized TSG substrates are shown to be valuable supports for studying surface nanobubbles by AFM in water and for addressing the relation between surface functionality and nanobubble formation and properties.

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confidence: 59%

Optimized Model Surfaces for Advanced Atomic Force Microscopy Studies of Surface Nanobubbles

2016

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“…After self-assembly of the monolayer, contact angles of 109 ± 2° were obtained for device A, 107 ± 2° for device B, 99 ± 1° for device C, and 66 ± 1° for device D (see SI-2). The observation that the surface energy of the mixed monolayers is a monotonic function of the mixing ratio in the solution from which the monolayers were prepared suggests that the mixing ratio in the monolayer is very similar to the mixing ratio in the solution 20 . This could be confirmed by amplitude-modulation atomic force microscopy (AM- content) have a relatively small memory ratio of 2.5 (see Section I in Figure 3b), the devices of series C (5% C 60 content) have a memory ratio of 26 (Section I in Figure 3c), and the devices of series D (100% C 60 content) have an excellent memory ratio of 43 (Section I in Figure 4d).…”

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confidence: 99%

Concept of a Molecular Charge Storage Dielectric Layer for Organic Thin‐Film Memory Transistors

Burkhardt¹,

Jedaa²,

Novák³

et al. 2010

Advanced Materials

116

121

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Citation for published item:furkh rdtD wF nd ted D eF nd xov kD wF nd i elD eF nd o¤ %t hovskyD uF nd tell iD pF nd rirs h D eF nd r likD wF @PHIHA 9gon ept of mole ul r h rge stor ge diele tri l yer for org ni thinE(lm memory tr nsistorsF9D edv n ed m teri lsFD PP @PQAF ppF PSPSEPSPVF Further information on publisher's website:httpXGGdxFdoiForgGIHFIHHPG dm FPHIHHHHQH Publisher's copyright statement: his is the epted version of the following rti leX furkh rdtD wF nd ted D eF nd xov kD wF nd i elD eF nd o¤ %t hovskyD uF nd tell iD pF nd rirs h D eF nd r likD wF @PHIHA 9gon ept of mole ul r h rge stor ge diele tri l yer for org ni thinE(lm memory tr nsistorsF9D edv n ed m teri lsFD PP @PQAF ppF PSPSEPSPVD whi h h s een pu lished in (n l form t httpXGGdxFdoiForgGIHFIHHPG dm FPHIHHHHQHF his rti le m y e used for nonE ommer i l purposes in ord n e ith ileyE gr erms nd gonditions for selfE r hivingFAdditional information:Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. In this work we report on a novel concept of an electrically programmable selfassembled molecular gate dielectric layer for OTFTs (see figure 1a) that can be reversibly charged and discharged and retains these digital states even when the supply voltage is removed. Due to the small thickness of the dielectric stack (app. 5.7 nm), the memory transistors operate with very small program and erase voltages of ± 2 V. Despite the extremely small dielectric thickness, the retention time is already promising (~6 hours with a read voltage of -750 mV applied continuously). The dielectric is a mixed monolayer of aliphatic and C 60 -functionalized phosphonic acid molecules (app. 2.1 nm thickness) on a patterned and plasma-oxidized aluminum gate electrode on a glass substrate. The aluminum oxide (AlO x ) contributes with a thickness of 3.6 nm to the dielectric layer stack 6 . As the aliphatic component, n-octadecylphosphonic acid 1 was chosen, which has already shown excellent insulating characteristics as the gate dielectric 6 . As the charge storage component, the C 60 -derivative 2 was synthesized to take advantage of the strong acceptor properties and reversible redox behavior of C 60 (Figure 1b and Supplementary Information SI-1) and of the self-assembly properties induced by the C 18 -aliphatic tail with phosphonic acid anchor group.Mixed self-assembled monolayers of 1 and 2 were created by a simple "one pot" solution content) have a relatively small memory ratio of 2.5 (see Section I in Figure 3b), the devices

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“…We see that the hysteresis is larger for N different from this (Fig. 3, Table 1), but it remains small in absolute terms and compared with surfaces that have been carefully tailored to minimize the hysteresis2324252627. Far beyond entanglement ( N= 1,571) it is 1.60° and at very small N ( N= 9) it is 0.97°.…”

Section: Resultsmentioning

confidence: 78%

A moving contact line as a rheometer for nanometric interfacial layers

et al. 2016

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How a liquid drop sits or moves depends on the physical and mechanical properties of the underlying substrate. This can be seen in the hysteresis of the contact angle made by a drop on a solid, which is known to originate from surface heterogeneities, and in the slowing of droplet motion on deformable solids. Here, we show how a moving contact line can be used to characterize a molecularly thin polymer layer on a solid. We find that the hysteresis depends on the polymerization index and can be optimized to be vanishingly small (<0.07°). The mechanical properties are quantitatively deduced from the microscopic contact angle, which is proportional to the speed of the contact line and the Rouse relaxation time divided by the layer thickness, in agreement with theory. Our work opens the prospect of measuring the properties of functionalized interfaces in microfluidic and biomedical applications that are otherwise inaccessible.

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Mixed Self-Assembled Monolayers of Alkanethiolates on Ultrasmooth Gold Do Not Exhibit Contact-Angle Hysteresis

Cited by 85 publications

References 23 publications

Optimized Model Surfaces for Advanced Atomic Force Microscopy Studies of Surface Nanobubbles

Optimized Model Surfaces for Advanced Atomic Force Microscopy Studies of Surface Nanobubbles

Concept of a Molecular Charge Storage Dielectric Layer for Organic Thin‐Film Memory Transistors

A moving contact line as a rheometer for nanometric interfacial layers

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