New insights in static and dynamic properties of Gibbs monolayer

Valentina Fazio; Jonas Ortegren; P. Koelsch; A. Andersen; Dieter Wantke; Helmuth Mohwald; Hubert Motschmann

doi:10.1117/12.509502

4 December 2003 New insights in static and dynamic properties of Gibbs monolayer

Valentina Fazio, Jonas Ortegren, P. Koelsch, A. Andersen, Dieter Wantke, Helmuth Mohwald, Hubert Motschmann

Proceedings Volume 5223, Physical Chemistry of Interfaces and Nanomaterials II; (2003) https://doi.org/10.1117/12.509502
Event: Optical Science and Technology, SPIE's 48th Annual Meeting, 2003, San Diego, California, United States

Abstract

In this paper we discuss selected equilibrium and dynamic properties of adsorption layers of soluble surfactants. The surface state has been investigated by nonlinear optical techniques based on second order χ⁽²⁾ effects which exhibit a high surface specificity and suppress bulk contributions. The surface tension isotherm σ(c )of the homologous series of n -alkyldimethylphosphine (n =8 −12) can be described by Frumki ’s equation of state which yields the surface interaction parameter, surface coverage and the corresponding area per molecule A . The comparison of the surface tension σ at a given area per molecule A reveals a strong alternation within the homologous series. Odd C_2n±1 layers show a lower surface tension than the adjacent even members C_2n of the homologous series. This effect is also present at low surface coverage (A =1.4nm²)and cannot be attributed to a differences in the chain-packing within a crystalline state. Infrared-Visible Sum-Frequency Generation Spectroscopy (SFGS)has been used to monitor the orientation and chain order within the aliphatic tail. SFGS spectra have been recorded for different chain lengths and at different areas per molecule. The analysis of the spectra yields an order parameter G which is proportional to the number of gauche defects within the aliphatic tail. The odd-even effect in the surface tension turned out to be accompanied by an odd-even effect in the order parameter G. The data suggest that an ordered structure has a bigger impact on the surface tension than an unordered structure. The odd-even effect is also observed in the orientation of the terminating methyl group as retrieved by polarization dependent SFGS measurements. The data shed some light in the relation between molecular and macroscopic properties. Furthermore surface dilatational viscoelastic properties of a fluorinated amphiphile have been measured by a novel version of the oscillating bubble. The oscillating bubble method generates a non-equilibrium state by a harmonic compression and expansion of the surface layer formed at the tip of a capillary. The surface state is monitored by Surface Second Harmonic Generation (SHG).This technique is highly surface specific and discriminates between monolayer and subsurface coverage. Our set-up allows to measure the monolayer coverage under dynamic conditions and to relate this to surface dilatational viscosity and elasticity. For a purely elastic surface layer the prediction of the Lucassen van den Temple model (LvdT)are fulfilled.

Citation Download Citation

Valentina Fazio, Jonas Ortegren, P. Koelsch, A. Andersen, Dieter Wantke, Helmuth Mohwald, and Hubert Motschmann "New insights in static and dynamic properties of Gibbs monolayer", Proc. SPIE 5223, Physical Chemistry of Interfaces and Nanomaterials II, (4 December 2003); https://doi.org/10.1117/12.509502

ACCESS THE FULL ARTICLE

INSTITUTIONAL
Select your institution to access the SPIE Digital Library.

SELECT YOUR INSTITUTION

PERSONAL
Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.

PERSONAL SIGN IN

No SPIE Account? Create one

PURCHASE THIS CONTENT

SUBSCRIBE TO DIGITAL LIBRARY

50 downloads per 1-year subscription

Members: $195

Non-members: $335 ADD TO CART

25 downloads per 1 - year subscription

Members: $145

Non-members: $250 ADD TO CART

PURCHASE SINGLE ARTICLE

Includes PDF, HTML & Video, when available

Members: $17.00

Non-members: $21.00 ADD TO CART

PROCEEDINGS
11 PAGES

DOWNLOAD PAPER SAVE TO MY LIBRARY

GET CITATION

RIGHTS & PERMISSIONS

Get copyright permission Get copyright permission on Copyright Marketplace

KEYWORDS

Molecules

Second-harmonic generation

Interfaces

Infrared radiation

Adsorption

Harmonic generation

Signal detection

Show All Keywords

Keywords/Phrases

Search In:

Publication Years