Abstract
In this chapter, I give a brief overview, which is biased by personal experience, on how various optical techniques can be used for characterization of soft matter at interfaces, including ellipsometry, light scattering, and total internal reflection geometries. Without discussing the technical details and theoretical foundations of the methods, I focus on what can be learned by applying the individual techniques.
Keywords
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsReferences
M. Born, E. Wolf, Principles of Optics (Pergamon Press, Oxford, 1975)
J. Lekner, Theory of Reflection:of Electromagnetic and Particle Waves (Springer, Dordrecht, 1987)
R.M.A. Azzam, N.M. Bashara, Ellipsometry and Polarized Light (Elsevier, Amsterdam, 1987)
H.G. Tompkins, A User’s Guide to Ellipsometry (Dover Publication Inc, New. York, 2006)
H. Fujiwara, Spectroscopic Ellipsometry: Principles and Applications (Wiley, New York, 2007)
Handbook of Ellipsometry, ed. by H.G. Tompkins, E.A. Irene (Springer, Heidelberg, 2004)
J.L. Keddie, Curr. Opin. Colloid Interface Sci. 6, 102 (2001)
D. Johannsmann, Investigations of soft organic films with ellipsometry. in Functional Polymer Films, ed. by W. Knoll, R.C. Advincula (Wiley-VCH Verlag GmbH & Co. KGaA, 2011)
W. Ogieglo, H. Wormeester, K.-J. Eichhorn, M. Wessling, N.E. Benes, In situ ellipsometry studies on swelling of thin polymer films: a review. Progress in Polymer Science, 2014, in ress. (http://www.sciencedirect.com/science/article/pii/S0079670014001063)
J.D. Willott, T.J. Murdoch, B.A. Humphreys, S. Edmondson, G.B. Webber, E.J. Wanless, Critical salt effects in the swelling behavior of a weak polybasic brush. Langmuir 30(7), 1827–1836 (2014)
J.C. Charmet, P.G. Degennes, J. Opt. Soc. Am. 73, 1777 (1983)
R. Toomey, M. Tirrell, In situ investigation of adsorbed amphiphilic block copolymers by ellipsometry and neutron reflectometry in soft matter characterization. ed. by R. Borsali, R. Pecora (Springer, Netherlands, 2008)
A. Stocco, G. Su, M. Nobili, M. Inab, D. Wang, In situ assessment of the contact angles of nanoparticles adsorbed at fluid interfaces by multiple angle of incidence ellipsometry. Soft Matter 10, 6999–7007 (2014)
B. Desbat, S. Castano, Brewster angle microscopy and imaging ellipsometry. in Encyclopedia of Biophysics ed. by G.C.K. Roberts (Springer, 2013), pp. 196–200
D.G.A.L. Aarts, M. Schmidt, H.N.W. Lekkerkerker, Direct visual observation of thermal capillary waves. Science 304(5672), 847–850 (2004)
S. Granick, S.C. Bae, Molecular motion at soft and hard interfaces: from phospholipid bilayers to polymers and lubricants. Annu. Rev. Phys. Chem. 58, 353 (2007)
C. Yu, J. Guan, K. Chen, S.C. Bae, Steve G., Single-molecule observation of long jumps in polymer adsorption. ACS Nano 7, 9735 (2013)
D. Prieve, Measurement of colloidal forces with TIRM. Adv Coll. Interface Sci. 82, 93 (1999)
P. Cicuta, I. Hopkinson, Recent developments of surface light scattering as a tool for optical-rheology of polymer monolayers. Colloids Surf A: Physicochem Eng. Aspects 233, 97–107 (2004)
A.R. Esker, C. Kim, H. Yu, Polymer monolayer dynamics. Adv. Polym. Sci. 209(1), 59–110 (2007)
R. Sigel, Light scattering near and from interfaces using evanescent wave and ellipsometric light scattering. Curr. Opin. Colloid Interface Sci. 14(6), 426–437 (2009)
F. de Fornel, Evanescent Waves, From Newtonian Optics to Atomic Optics, vol 73 (Springer Series in Optical Sciences, 2010)
Acknowledgments
Part of the work was presented as as a lecture at the SOMATAI summer school 2014 in Berlin. The support of the Greek ESPA programme Areistea RINGS is acknowledged.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Appendix 1: Total Internal Reflection and Evanescent Field
Appendix 1: Total Internal Reflection and Evanescent Field
Electromagnetic near fields designate non-radiative fields that are localized near an object, so to say at the surface of the object. Optical near fields offer a convenient way to probe interfaces. They extend over one wavelength or so. In particular they can be used to excite scattering or fluorescence.
One such near field is the evanescent waves present in the medium of lower refractive index at total internal reflection. When reflectivity coefficients are one, there is nonetheless a near field penetrating the medium of lower refractive index. It is well described by the reflectivity coefficients, with r p and r s being complex numbers of module 1 (Fig. 13.4).
In particular it is possible to compute the penetration depth.
The evanescent field writes [2] as \( E_{ev} = E_{0} \,e^{ - \kappa z} e^{i(kx - \omega t)} \) with the “penetration wave vector” \( \kappa = 1/d_{p} = \frac{{2\pi n_{1} }}{\lambda }\sqrt {\sin^{2} \theta - \frac{{n_{2}^{2} }}{{n_{1}^{2} }}} \) and the “propagation wave vector” along the interface \( k = \frac{{2\pi n_{1} }}{\lambda }\sin \theta \).
The other may be less appreciated length scale associated with TIR is the Goss Haenchen shift, that describes the lateral shift of the beam [2]. Looking into the reflectivity coefficient, a phase shift appears under TIR, which also depends on the polarization and the incidence angle. This phase shift is the sign of a time (length) associated with the TIR.
The EW produced at TIR can be associated with many different detection schemes [22], ellipsometry, light scattering, fluorescence, Raman, IR, and recently optical rotation.
The critical angle is independent of the polarization for non-birefringent materials, and so is the penetration depth. However the s and p polarized light undergo different phase shift under TIR. The difference of phase shift is what ellipsometry under total internal reflection will measure. The penetration depth can be varied by changing the incidence angle. A larger optical contrast between the two materials will provide a shorter penetration depth, as will larger incidence angles. As an example, the field penetration depth d p at interface between high refractive index incidence medium (n 1 = 2) with water (n 2 = 1.33) can become as low as 60 nm for a wavelength of 532 nm.
Rights and permissions
Copyright information
© 2016 Springer International Publishing Switzerland
About this chapter
Cite this chapter
Loppinet, B. (2016). Characterization of Soft Matter at Interfaces by Optical Means. In: Lang, P., Liu, Y. (eds) Soft Matter at Aqueous Interfaces. Lecture Notes in Physics, vol 917. Springer, Cham. https://doi.org/10.1007/978-3-319-24502-7_13
Download citation
DOI: https://doi.org/10.1007/978-3-319-24502-7_13
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-24500-3
Online ISBN: 978-3-319-24502-7
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)