Speaker
Jostein Bø Fløystad
(Norwegian University of Science and Technology)
Description
With the ability to control the structure of multiphase materials for applications on the nano- and
mesoscale, methods for imaging these materials are becoming increasingly important. Especially
techniques able to image sub-micron structures of functional materials in operando are in high
demand, as these problems often fall outside the range of electron microscopy due to requirements of
complex sample environments or less invasive sample preparation procedures.
Ptychography is a technique for lensless imaging, implemented for X-rays over the last few years and
still in rapid development[1, 2]. Relying on an iterative reconstruction algorithm to form real space
images from a series of coherent small-angle scattering patterns, thus solving the “phase problem”, it
yields quantitative images of both the absorption and phase shift induced by the object. The
penetrating power of X-rays allows ptychography to work also in customized sample environments,
such as high temperatures and specific gas atmospheres. Using tomography methods, ptychography
can also provide three-dimensional images[3].
We discuss the potential of this new imaging technique for solving problems in materials science,
especially related to structure investigations of highly inhomogenous materials with structures on
length scales approaching 10 nm. Examples will be drawn from our recent work on hydration of
isolated silk fibres, where we have used three dimensional quantitative imaging by X-ray
ptychography to show that silk fibres swell anisotropically through absorption of water in the protein
matrix when the surrounding atmosphere changes from low to high relative humidity, while the pore
structure is left unchanged[4].
References
[1] J. M. Rodenburg et al., Phys. Rev. Lett. 98, 034801 (2007)
[2] P. Thibault et al., Science 321, 379–382 (2008)
[3] M. Dierolf et al., Nature 467, 436–439 (2010)
[4] M. Esmaeili et al., Macromolecules 46, 434–439 (2013)
Primary author
Jostein Bø Fløystad
(Norwegian University of Science and Technology)
Co-authors
Dr
Ana Diaz
(Paul Scherrer Institut)
Dr
Dag Werner Breiby
(Norwegian University of Science and Technology)
Dr
Jens Wenzel Andreasen
(Technical University of Denmark)
Dr
Kristin Høydalsvik
(Norwegian University of Science and Technology)
Dr
Manuel Guizar-Sicairos
(Paul Scherrer Institut)
Dr
Morteza Esmaeili
(Norwegian University of Science and Technology)
