Recent synchrotron radiation microdiffraction experiments on polymer and biopolymer fibers

García-Gutiérrez, Mari Cruz; Gourrier, Aurélien; Roth, Stephan V.

doi:10.1007/s00216-003-1976-0

Cited by 28 publications

(22 citation statements)

References 37 publications

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“…A reasonable explanation for this observation is that the material expands laterally under the pressure of the indenter during the deformation process, which leads to a reduced thickness in the centre of the indentation. This is a general effect observed in all previous experiments of this type performed on polymer fibres (Gourrier et al, 2002(Gourrier et al, , 2005García-Gutié rrez et al, 2004;Riekel et al, 2003). The integrated SAXS intensity image therefore yields no additional structural information relative to the effect of the deformation process.…”

Section: Hair Specimensupporting

confidence: 59%

“…An eggshell section of 110 mm thickness was prepared following a well established procedure (Lammie et al, 2006). A human hair sample of approximately 85 mm in diameter was used without any chemical treatment and deformed using a microindentation technique using a force of 1000 mN, at a rate of 100 mN s À1 for 10 s, following a protocol established in previous experiments with synthetic polymer fibres (Gourrier et al, 2002(Gourrier et al, , 2005García-Gutié rrez et al, 2004;Riekel et al, 2003).…”

Section: Methodsmentioning

confidence: 99%

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Scanning X-ray imaging with small-angle scattering contrast

et al. 2007

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An X-ray scanning imaging technique using the integrated intensity of the smallangle X-ray scattering (SAXS) signal is presented. The technique is based on two-dimensional scanning of a thin sample section with an X-ray microbeam, collecting SAXS patterns at every scanning step using a two-dimensional detector. The integrated intensity within pre-defined regions of interest of the SAXS patterns is used to image bulk nanostructural features in the specimen with micrometre resolution which are usually not accessible by other methods such as light microscopy or scanning electron microscopy. The possibilities and limitations of the method are discussed with particular emphasis on the sources of contrast in the SAXS region for three biological specimens: cortical bone, eggshell and hair. Two main sources of image contrast are identified in the form of orientation effects for strongly anisotropic systems like cortical bone and differences in the local volume fraction of the scattering entities in eggshell. Moreover, other parameters than the integrated intensity can be quantitatively deduced from the SAXS patterns, for instance, the mean thickness of mineral platelets in bone or the strain distributions in a hair deformed plastically by microindentation.

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Section: Hair Specimensupporting

confidence: 59%

Section: Methodsmentioning

confidence: 99%

Scanning X-ray imaging with small-angle scattering contrast

et al. 2007

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“…The mechanical properties do not change linearly over the entire humidity range, but at least in the case of silkworm silk display a critical humidity at approximately 70% relative humidity (RH) above which the decay of the mechanical modulus with humidity is significantly enhanced [5]. Structural models for silk fibers have benefited from the rapid evolution of synchrotron x-ray microdiffraction techniques [6], nuclear magnetic resonance techniques [7], as well as since recently also neutron techniques [8]. Both silkworm silk and the morphologically similar spider silk are hierarchically structured protein polymers consisting of nanometer-sized Alanine-rich β-sheet crystallites embedded in an amorphous disordered Glycine-rich matrix.…”

Section: Introductionmentioning

confidence: 99%

Increased molecular mobility in humid silk fibers under tensile stress

et al. 2011

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Silk fibers are semi-crystalline nanocomposite protein fibers with an extraordinary mechanical toughness which changes with humidity. Diffusive or overdamped motion on a molecular level is absent in dry silkworm silk, but present in humid silk at ambient temperature. This microscopic diffusion distinctly depends on the externally applied macroscopic tensile force. Quasi-elastic and inelastic neutron scattering data as a function of humidity and of tensile strain on humid silk fibers support the model that both the adsorbed water and parts of the amorphous polymers participate in diffusive motion and are affected by the tensile force. Notably, the quasi-elastic linewidth of humid silk at 100% relative humidity increases significantly with the applied force. The effect of the tensile force is discussed in terms of an increasing alignment of the polymer chains in the amorphous fraction with increasing tensile stress which changes the geometrical restrictions of the diffusive motions.

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“…11-13 for reviews͒, and has applied them particularly to polymers and biopolymers. [13][14][15][16][17] User applications at the ID13 beamline include many fields of modern materials science covering among others metals, 18 carbon fibers, 19 synthetic polymers, [20][21][22] as well as biopolymers and biological tissues. [23][24][25][26][27][28][29] In the meanwhile, x-ray microbeams with high photon flux are available also at other sites, and dedicated instruments for scanning SAXS/WAXS have been built 30 or are in the construction phase.…”

Section: Introductionmentioning

confidence: 99%

From diffraction to imaging: New avenues in studying hierarchical biological tissues with x-ray microbeams (Review)

Paris

2008

Biointerphases

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Load bearing biological materials such as bone or arthropod cuticle have optimized mechanical properties which are due to their hierarchical structure ranging from the atomic/molecular level up to macroscopic length scales. Structural investigations of such materials require new experimental techniques with position resolution ideally covering several length scales. Beside light and electron microscopy, synchrotron radiation based x-ray imaging techniques offer excellent possibilities in this respect, ranging from full field imaging with absorption or phase contrast to x-ray microbeam scanning techniques. A particularly useful approach for the study of biological tissues is the combination x-ray microbeam scanning with nanostructural information obtained from x-ray scattering [small-angle x-ray scattering (SAXS) and wide-angle x-ray scattering (WAXS)]. This combination allows constructing quantitative images of nanostructural parameters with micrometer scanning resolution, and hence, covers two length scales at once. The present article reviews recent scanning microbeam SAXS/WAXS work on bone and some other biological tissues with particular emphasis on the imaging capability of the method. The current status of instrumentation and experimental possibilities is also discussed, and a short outlook about actual and desirable future developments in the field is given.

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Recent synchrotron radiation microdiffraction experiments on polymer and biopolymer fibers

Cited by 28 publications

References 37 publications

Scanning X-ray imaging with small-angle scattering contrast

Scanning X-ray imaging with small-angle scattering contrast

Increased molecular mobility in humid silk fibers under tensile stress

From diffraction to imaging: New avenues in studying hierarchical biological tissues with x-ray microbeams (Review)

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