Synchrotron X-ray techniques for the investigation of structures and dynamics in interfacial systems

https://doi.org/10.1016/j.cocis.2014.03.006Get rights and content

Highlights

  • This is a review of recent results obtained in the last years by synchrotron radiation.

  • Techniques: reflectivity (XRR) grazing incidence diffraction (GIXRD) fluorescence (GIXF) photon correlation (XPCS, GI-XPCS)

  • Systems: floating Langmuir monolayers, supported films, gels and colloids either in 3D or as 2D interfacial layers

Abstract

This review focuses on recent results obtained by synchrotron X-ray techniques applied to the characterization of interfacial systems, with main emphasis on flat interfaces and on colloidal systems. The techniques covered are, for structural determinations: X-ray reflectivity (XRR), grazing incidence X-ray diffraction (GIXRD) and grazing incidence X-ray excited fluorescence (GIXF), while dynamics are investigated by X-ray photon correlation spectroscopy (XPCS) mainly in the grazing-incidence geometry (GIXPCS).

The systems reviewed are, in order of growing complexity, floating Langmuir monolayers, supported films of lipids and proteins, polymeric films, buried interfaces, colloidal systems and gels formed by colloids either in 3D or in the form of 2D interfacial layers. Recent results are critically discussed, and some interesting directions of development are outlined, having also in mind new technical developments such as X-ray free electron laser sources and micro-focused synchrotron beamlines.

Introduction

This review focuses on recent results, and on the instrumental developments, which took place in the last years, in the diverse research fields interested by the application of synchrotron radiation to problems in interface and colloid science. Special emphasis is given to fluid interfaces (either air–water or liquid–liquid interfaces), to buried interfaces and to colloidal systems.

I shall begin the review discussing structural investigations. The main techniques in this case are X-ray reflectivity, (either in specular or in off-specular modes) and grazing incidence X-ray diffraction, often complemented successfully by grazing incidence X-ray fluorescence, which provides elemental sensitivity along the direction perpendicular to the interface. Section 2 is devoted to soft interfaces (either air/water or liquid/liquid) while Section 3 is devoted to films deposited on solid support.

In Section 4, the focus is on the dynamics of interfaces and of colloidal systems, accessed by X-ray photon correlation spectroscopy (XPCS) on the nanometer scale and on the timescale from the few milliseconds to several hours. XPCS is the equivalent of dynamic light scattering, but performed by X-rays. As such, it is able to follow the time evolution of correlation functions, and to characterize the evolution of systems undergoing aging. I will emphasize some recent works showing how XPCS proved able to access directly dynamical heterogeneities, which constitute an important signature of the different states of dynamically arrested systems. Finally, in Section 5, I shall discuss instrumental developments, some of which undertaken aiming at the implementation of these techniques at new microfocused beamlines and at the free-electron laser facilities that start now to be operational.

Section snippets

Structural investigations of systems at the air–water and liquid–liquid soft interfaces

Langmuir monolayers at the air–water interface are relatively simple systems, and have been studied for many years; though their structure is fairly well understood only in those cases where they are formed by simple molecules [1], [2]. On the contrary, much less is known about structure, dynamics and interfacial behavior of biologically relevant films made of proteins, and of macromolecular aggregates and colloidal layers which are of large technological relevance.

In this class, important

Structural investigation of buried interfaces and solid supported films

Moving from air–water to buried liquid–liquid interfaces represents an increase in experimental difficulty: this requires usage of higher energy X-ray beams, to overcome the attenuation of X-rays by the condensed liquid phases. However, this is justified by the importance of such interfaces: many technological processes, including food processing, foam stabilization, and many biological systems, can be understood, controlled and schematized to a good degree by this class of systems. A recent

Study of the dynamics by X-ray photon correlation spectroscopy (XPCS)

X-ray photon correlation spectroscopy (XPCS) is the extension of photon correlation spectroscopy (also called dynamic light scattering [36]) to the X-ray regime. It permits to access an otherwise inaccessible region of the space–time plane corresponding to localized and slow motions, e.g. taking place on the nm-scale and on the 10 3–102 second time scales. XPCS technique was pioneered at the National Synchrotron Light Source at Brookhaven National Laboratory by Sutton, Mochrie and co-workers in

Instrumental developments

In recognition of the increasing importance of the application of X-rays to surface science, dedicated new beamlines are being built at the diverse facilities around the world. E.g. a dedicated beamline has been designed, constructed and optimized at beamline 8-ID-E at the Advanced Photon Source (Argonne National Lab) for high-resolution and coherent grazing incidence X-ray scattering (GIXS) experiments with applications for in situ and real-time studies of nanostructures and nano-composites at

Conclusions and outlook

In conclusion, a suite of sophisticated synchrotron-based techniques (see Fig. 6) are becoming of increasingly common use for the characterization of soft interfaces, often accessing otherwise unattainable information on the structure and the dynamics of these complex systems.

A promising evolution is the development of sophisticated sample environment including “ancillary equipment” especially designed to allow simultaneous characterization by different techniques, to cover the broad time- and

Acknowledgments

I am deeply indebted to Pietro Cicuta, Davide Orsi, Diego Pontoni and Beatrice Ruta for critical reading of the manuscript and for stimulating discussions, to Oleg Konovalov for initiating me to surface science by synchrotron radiation a long time ago, to Andrei Fluerasu for many interesting experiments together, and mostly to Anders Madsen for his introduction to the subtleties of the XPCS technique.

I also thank the co-authors of references [15], [63], [64], [67], [79•], [95••], [96], [98],

References and recommended reading•,•• (118)

  • C. O'Hern et al.

    Random packings of frictionless particles

    Phys Rev Lett

    (2002)
  • V.M. Kaganer et al.

    Structure and phase transitions in Langmuir monolayers

    Rev Mod Phys

    (1999)
  • R. Tredgold

    Order in thin organic films

    (2005)
  • K. Kisko et al.

    Self-assembled films of hydrophobin proteins HFBI and HFBII studied in situ at the air/water interface

    Langmuir

    (2009)
  • A. Singh et al.

    Measuring elastic properties of a protein monolayer at water surface by lateral compression

    Soft Matter

    (2013)
  • S. Mora et al.

    X-ray surface scattering investigation of Langmuir films: phase transitions and elastic properties

    Europhys Lett

    (2004)
  • L. Wiegart et al.

    Thermodynamic and structural properties of phospholipid langmuir monolayers on hydrosol surfaces

    Langmuir

    (2005)
  • D.K.G. De Boer

    Glancing-incidence X-ray fluorescence of layered materials

    Phys Rev B

    (1991)
  • A. Körner et al.

    Quantitative determination of lateral concentration and depth profile of histidine-tagged recombinant proteins probed by grazing incidence X-ray fluorescence

    J Phys Chem B

    (2013)
  • W. Abuillan et al.

    Physical interactions of fish protamine and antisepsis peptide drugs with bacterial membranes revealed by combination of specular X-ray reflectivity and grazing-incidence X-ray fluorescence

    Phys Rev E

    (2013)
  • W. Abuillan et al.

    Quantitative determination of the lateral density and intermolecular correlation between proteins anchored on the membrane surfaces using grazing incidence small-angle X-ray scattering and grazing incidence X-ray fluorescence

    J Chem Phys

    (2012)
  • C. Jeworrek et al.

    Structure and phase behavior of archaeal lipid monolayers

    Langmuir

    (2011)
  • C. Stefaniu et al.

    Polymer-capped magnetite nanoparticles change the 2D structure of DPPC model membranes

    Soft Matter

    (2012)
  • L. Cristofolini et al.

    Doping-induced conductivity transitions in molecular layers of polyaniline: detailed structural study

    Langmuir

    (2009)
  • K. Wojciechowski et al.

    Anion-specificity at water–air interface probed by total reflection X-ray fluorescence (TRXF)

    Colloids Surf A Physicochem Eng Aspects

    (2012)
  • S. Xiong et al.

    Revealing the interfacial self-assembly pathway of large-scale, highly-ordered, nanoparticle/polymer monolayer arrays at an air/water interface

    Nano Lett

    (2013)
  • L. Isa et al.

    Measuring single-nanoparticle wetting properties by freeze-fracture shadow-casting cryo-scanning electron microscopy

    Nat Commun

    (2011)
  • D.C.E. Calzolari et al.

    Nanoscale structure of surfactant-induced nanoparticle monolayers at the oil–water interface

    Soft Matter

    (2012)
  • L. Isa et al.

    Core–shell nanoparticle monolayers at planar liquid–liquid interfaces: effects of polymer architecture on the interface microstructure

    Soft Matter

    (2013)
  • A.G. Richter et al.

    Using in situ X-ray reflectivity to study protein adsorption on hydrophilic and hydrophobic surfaces: benefits and limitations

    Langmuir

    (2013)
  • W.H. Briscoe et al.

    Synchrotron XRR study of soft nanofilms at the mica–water interface

    Soft Matter

    (2012)
  • W.H. Briscoe et al.

    Applying grazing incidence X-ray reflectometry (XRR) to characterising nanofilms on mica

    J Colloid Interface Sci

    (2007)
  • F. Speranza et al.

    Quiescent bilayers at the mica–water interface

    Soft Matter

    (2013)
  • L. Cristofolini et al.

    Structural study of the DNA dipalmitoylphosphatidylcholine complex at the air–water interface

    Biomacromolecules

    (2007)
  • E. Mele et al.

    Multilevel, room-temperature nanoimprint lithography for conjugated polymer-based photonics

    Nano Lett

    (2005)
  • H. Hlaing et al.

    Nanoimprint-induced molecular orientation in semiconducting polymer nanostructures

    ACS Nano

    (2011)
  • S.H. Kim et al.

    Physicochemically stable polymer-coupled oxide dielectrics for multipurpose organic electronic applications

    Adv Funct Mater

    (2011)
  • M. Kotera et al.

    Microstructures of BPDA-PPD polyimide thin films with different thicknesses

    Polymer (Guildf)

    (2013)
  • C.E. Ashley et al.

    Convective assembly of 2D lattices of virus-like particles visualized by in-situ grazing-incidence small-angle X-ray scattering

    Small

    (2011)
  • M. Bass et al.

    Surface-induced micelle orientation in nafion films

    Macromolecules

    (2011)
  • M. Bass et al.

    Surface structure of Nafion in vapor and liquid

    J Phys Chem B

    (2010)
  • B.J. Berne et al.

    Dynamic light scattering

    (2000)
  • M. Sutton et al.

    Observation of speckle by diffraction with coherent X-rays

    Nature

    (1991)
  • M. Sutton

    A review of X-ray intensity fluctuation spectroscopy

    C R Phys

    (2008)
  • G. Gruebel et al.

    X-ray photon correlation spectroscopy (XPCS)

  • R.L. Leheny

    XPCS: nanoscale motion and rheology

    Curr Opin Colloid Interface Sci

    (2012)
  • T. Hoshino et al.

    Surface and interface analyses of polymer brushes by synchrotron radiation

    J Phys Soc Jpn

    (2012)
  • O. Dauchot et al.

    Dynamical heterogeneity close to the jamming transition in a sheared granular material

    Phys Rev Lett

    (2005)
  • A. Madsen et al.

    Beyond simple exponential correlation functions and equilibrium dynamics in X-ray photon correlation spectroscopy

    New J Phys

    (2010)
  • J. Forrest et al.

    Effect of free surfaces on the glass transition temperature of thin polymer films

    Phys Rev Lett

    (1996)
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