Reversible collapse of the Langmuir films of a series of triphenylsilyl ether-terminated amphiphiles

DeVries, Christine A.; Haycraft, James J.; Han, Qiang; Noor-e-Ain, Farhana; Raible, Joseph; Dussault, Patrick H.; Eckhardt, Craig J.

doi:10.1016/j.tsf.2010.11.029

Cited by 7 publications

(8 citation statements)

References 27 publications

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“…Furthermore, the mechanisms of monolayer collapse also appear to be dependent on the amount of surfactant spread 25 and on the capacity for forming nematic clusters. 26 However, none of these mechanisms have been proven conclusively. For instance, it has been reported that for some phospholipids showing phase coexistence, large and isolated folds rather than vesicles are observed at the boundaries between the two phases; 14 these folds remain connected to the monolayers, which would permit the film to reverse when expanded.…”

Section: Introductionmentioning

confidence: 99%

Understanding the Collapse Mechanism in Langmuir Monolayers through Polarization Modulation-Infrared Reflection Absorption Spectroscopy

Goto

Caseli

2013

Langmuir

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The collapse of films at the air-water interface is related to a type of 2D-to-3D transition that occurs when a Langmuir monolayer is compressed beyond its stability limit. Studies on this issue are extremely important because defects in ultrathin solid films can be better understood if the molecular mechanisms related to collapse processes are elucidated. This paper explores how the changes of vibration of specific groups of lipid molecules, as revealed by polarization modulation-infrared reflection absorption spectroscopy (PM-IRRAS), are affected by the monolayer collapse. Different mechanisms of collapse were studied, for those lipids that undergo constant-area collapse (such as stearic acid) and for those that undergo constant-pressure collapse (such as DPPC, DPPG, and DODAB). Lipid charges also affect the mechanism of collapse, as demonstrated for two oppositely charged lipids.

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Section: Introductionmentioning

confidence: 99%

Understanding the Collapse Mechanism in Langmuir Monolayers through Polarization Modulation-Infrared Reflection Absorption Spectroscopy

Goto

Caseli

2013

Langmuir

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“…The shapes of their isotherms are reminiscent of those observed by Haycraft et al for so-called “bulge amphiphiles”, i.e., molecules with a large nonpolar group attached to the hydrophobic end of the hydrocarbon chain. 87 , 88 They also observed a plateauing of the surface pressure after the collapse, accompanied by the appearance of bright spots in the BAM images of the film, which in time coalesced into larger formation. Moreover, they also observed cases of large hysteresis in the compression–expansion cycles.…”

Section: Discussionmentioning

confidence: 91%

Reversible Photoisomerization in Thin Surface Films from Azo-Functionalized Guanosine Derivatives

et al. 2021

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Two novel azo-functionalized guanosine derivatives were synthesized, and their photoisomerization process was investigated in molecular monolayers at the air–water interface and in the Langmuir–Blodgett (LB) films on solid substrates. Measurements of surface pressure vs area isotherms, surface potential measurements, UV–visible (vis) absorption spectroscopy, Brewster angle microscopy (BAM), and atomic force microscopy (AFM) were performed. Despite not having a typical amphiphilic molecular structure, the derivatives formed stable films on the water surface. They could also undergo repeated photoisomerization in all of the investigated thin-film configurations. The observations suggest that in the films at the air–water interface, the molecules first exhibit a conformational change, and then they reorient to an energetically more favored orientation. In the LB films transferred onto solid substrates, the isomerization process occurs on a similar time scale as in solution. However, the isomerization efficiency is about an order of magnitude lower than that in solution. Our results show that DNA nucleobases functionalized with azobenzene moieties are suitable candidates for the fabrication of photoactive two-dimensional (2D) materials that can provide all beneficial functionalities of DNA-based compounds.

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“…The behavior of films from pure nucleobase derivatives that was observed in our experiments is reminiscent of the one observed by Haycraft et al who studied Langmuir films of so-called bulge amphiphiles, i.e., molecules with a large group attached to the hydrophobic end of the hydrocarbon chain. 58,59 They also observed a plateauing of surface pressure after the collapse, accompanied by the appearance of bright spots in the BAM images of the film, which in time coalesced into larger formations. Moreover, they also observed cases of large hysteresis in the compression–expansion cycles.…”

Section: Discussionmentioning

confidence: 91%

Photoisomerizable Guanosine Derivative as a Probe for DNA Base-Pairing in Langmuir Monolayers

2019

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Mixtures of azo-functionalized amphiphilic derivatives of guanosine and of amphiphilic derivatives of other DNA nucleobases were deposited at an air–water interface and repeatedly irradiated with light of 340 and 440 nm wavelengths. The consequent switching between cis and trans configurations of the azobenzene moiety caused changes in the surface pressure of the film, which were analyzed using a model based on the two-dimensional Van der Waals equation of state. For mixed films of guanosine and cytidine derivatives, the analysis revealed a significant modification of the strength of intermolecular interaction caused by the optical irradiation, while no such modifications were identified in mixed films involving other nucleobases. The difference is attributed to light-induced breaking of the hydrogen bonding that is established only between specific nucleobases. The results demonstrate that photosensitive nucleoside derivatives can be used as an efficient probe for base-pairing in Langmuir monolayers.

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Reversible collapse of the Langmuir films of a series of triphenylsilyl ether-terminated amphiphiles

Cited by 7 publications

References 27 publications

Understanding the Collapse Mechanism in Langmuir Monolayers through Polarization Modulation-Infrared Reflection Absorption Spectroscopy

Understanding the Collapse Mechanism in Langmuir Monolayers through Polarization Modulation-Infrared Reflection Absorption Spectroscopy

Reversible Photoisomerization in Thin Surface Films from Azo-Functionalized Guanosine Derivatives

Photoisomerizable Guanosine Derivative as a Probe for DNA Base-Pairing in Langmuir Monolayers

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