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The surface activities of two amphiphilic diblock copolymers containing 2-ethyl hexyl methacrylate- b-N, N′-dimethylacrylamide ( EHMA- b- DMA) possessing hydrophobic segments of different chain lengths were studied. Toward this end, surface pressure−area ( π− A) isotherms, static and dynamic elasticities and the ν exponent of the excluded volume of polymers forming monolayers at the air−water interface were measured. The degree of hydrophobicity of the diblock copolymers was estimated by determining their surface energy values from contact angle measurements. The morphology of the monolayer at different surface pressures was studied by Brewster angle microscopy. Both copolymers were observed to form stable and elastic monolayers, and their collapse was observed to occur at similar surface pressures. Langmuir−Blodgett films were successfully deposited onto mica and silicon wafers and analysed by atomic force microscopy. © 2014 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Highlights: [•] We report the in situ synthesis of gold nanoparticles at the air–water interface. [•] Nanoparticles were obtained by reaction between PVP monolayers and AuCl4 − ions. [•] Monolayers of PVP on aqueous AuCl4 − show differences in elasticity and stability. [•] Gold nanoparticles were confirmed by spectroscopy UV–Vis and SEM. [ABSTRACT FROM AUTHOR]

Surface activity of poly(methacrylate)s containing phthalimidoalkyl groups was studied. Surface pressure-area isotherms (π-A) at the air-water interface were determined. These polymers form stable and condensed monolayers. The monolayers are more condensed and the limiting surface area A0 values decrease when the number of the methylene groups in the lateral chains increases. Surface pressure variation at the semidilute region of the monolayers was expressed in terms of the scaling laws as power function of the surface concentration. The static elasticity εo and the exponent of the excluded volume v were determined. The hydrophobicity degree of polymers was estimated from the determination of the total surface free energy values by wettability measurements. Molecular dynamic simulation (MDS) was performed in order to explain the experimental behavior of polymers at the air-water interface. [ABSTRACT FROM AUTHOR]

The static and dynamic behavior of the Langmuir monolayers of poly(ester)s containing germanium and silicon in the main chain (Scheme 1) is reported. True monolayers are found for all the poly(ester)s studied. The isotherms of surface pressure versus surface area for poly(ester)s exhibit a behavior of the expanded-type monolayers and that of condensed-type monolayers. It was observed that the addition of an hydrophilic polymer such as poly(monomethyl itaconate) to the water subphase produces significant changes in the isotherm properties. The interfacial rheology of the poly(ester)s monolayers has also been studied by using Oscillatory Barrier Experiments in a low-frequency range. It was found that the elasticity and the dilational viscosity increase from diluted monolayers until a surface concentration about 20 × 10 mg cm. The static and dynamic elasticities were found to be very similar for the poly(ester)s over the dilute range. It was possible to conclude that these poly(ester)s form extremely viscoelastic monolayers. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 [ABSTRACT FROM AUTHOR]

Abstract: Synthesis, characterization and behavior at the air–water interface of A–B–A triblock copolymers are reported. The copolymers consist of a poly(ethylene oxide) central block and poly(ε-caprolactone) lateral blocks. The synthesis was controlled in order to obtain central and lateral blocks of variable length. Copolymer characterization was performed by FTIR and 1H NMR spectroscopy, size exclusion chromatography (SEC), and thermal analysis. Monolayers of the copolymers at the air–water interface were obtained by the Langmuir technique and the respective isotherms were obtained by monolayer compression. The limiting area per repeat unit (A o) and the critical exponent of the excluded volume (ν) for spread monolayers were obtained. The static elasticity (ε 0) of the monolayers was also determined. The obtained results allow proposing a schematic model of the orientation of the different blocks during the compression of the respective monolayers. [Copyright &y& Elsevier]

Abstract: A comparative study of spread and adsorbed monolayer of poly(ethylene oxide)s of different molecular weight hydrophobically modified with alkyl isocyanates of different length chain is reported. The modification of the polymer was carried out according to reported procedures. The polymers obtained were studied at the air–water interface by Langmuir isotherms for spread monolayers and by Gibbs isotherms for the adsorption process. Isotherms obtained are interpreted in terms of the hydrophobic and hydrophilic balance of the polymers. Limiting area per repeating unit () and collapse pressure () from spread monolayers were obtained. Spread monolayers of the hydrophobically modified polymers show larger collapse pressure values than unmodified polymer monolayers. In the adsorption process the excess surface concentration , area per repeat unit σ, and efficiency of the adsorption were determined. The values of the area occupied per repeat unit in adsorbed monolayer (σ) were larger than those of the spread monolayer. The efficiency of the adsorption of poly(ethylene oxide)s increases with the hydrophobic modification and with the alkyl chain length. [Copyright &y& Elsevier]