Chain conformation of poly(dimethyl siloxane) at the air/water interface by sum frequency generation

Langmuir : the ACS Journal of Surfaces and Colloids
Chanjoong KimHyuk Yu

Abstract

This is to report a study of chain conformation of poly(dimethylsiloxane) (PDMS) in spread monolayers at the air/water interface (A/W) with the aid of vibrational sum frequency spectroscopy (VSFS). We find that methyl groups of PDMS chains at the interface are completely disordered in the dilute regime of the surface density. At higher surface densities, however, the two methyl groups on the repeating unit point into the air asymmetrically; one points more normal to the interface, whereas the other lies more parallel to the interface. In the first collapsed regime, where the surface pressure of the PDMS monolayer reaches a plateau value of 8.7 mN/m, the signal intensity at 2915 cm (-1), assigned to the symmetric vibrational frequency of the methyl groups, is found independent of the surface density. On the basis of this finding, we propose that PDMS chains, in the first collapse regime at the A/W, form asymmetric layers. Thus, our proposal lends support to earlier works by Langevin's group to refute a widely speculated helix model that was based on energy minimization in the crystalline state of PDMS. In short, the energy consideration in the bulk crystalline state does not provide meaningful guidance as to the chain conformati...Continue Reading

References

Oct 29, 1996·Proceedings of the National Academy of Sciences of the United States of America·Y R Shen
Apr 28, 2001·Annual Review of Physical Chemistry·G Richmond
Apr 25, 2002·Annual Review of Physical Chemistry·Zhan ChenGabor A Somorjai

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Citations

Jul 4, 2013·Langmuir : the ACS Journal of Surfaces and Colloids·Zhengzheng LiaoIvan J Dmochowski
Aug 12, 2015·Langmuir : the ACS Journal of Surfaces and Colloids·Erum MansuriChristine E DeWolf
Jun 22, 2016·European Journal of Pharmaceutics and Biopharmaceutics : Official Journal of Arbeitsgemeinschaft Für Pharmazeutische Verfahrenstechnik E.V·Stefanie FunkeWolfgang Friess
Sep 17, 2020·Macromolecular Rapid Communications·Michael J Owen
Mar 23, 2020·The Journal of Chemical Physics·Deepak TomarKailash C Jena
Dec 6, 2019·Journal of the American Chemical Society·Azhad U ChowdhuryBenjamin Doughty
Jun 25, 2010·Langmuir : the ACS Journal of Surfaces and Colloids·C BernardiniF A M Leermakers
Jul 9, 2021·ACS Applied Materials & Interfaces·Lu LinBenjamin Doughty
Dec 12, 2017·ACS Macro Letters·Brandon L PetersGary S Grest
Feb 9, 2011·Langmuir : the ACS Journal of Surfaces and Colloids·C BernardiniF A M Leermakers
Feb 12, 2018·ACS Biomaterials Science & Engineering·Veli OzbolatIbrahim T Ozbolat

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