SAXS analysis

What is SAXS analysis used for?

SAXS analysis is used to derive the low-resolution nanostructure of materials, offering morphological detail and information about internal structure. This includes shape, size, crystallinity, porosity, and orientation.

Applications in polymer characterization

In polymer characterization, SAXS is often used to examine the pore structure of cellulose and cellulose carbamate fibers and man-made bone. It is also used to determine the long periods of polypropylene film stripes. In polymer research, SAXS helps optimize material properties and enhance performance. 

Applications in nanomaterial analysis

SAXS has widespread applications in the study of nanoparticles, colloids, and nanostructured materials. One such involves the characterization of the growth mechanism and self-assembly of silica particles during production. SAXS is also used to enhance the mechanical properties of nanocomposites.

SAXS in the pharmaceutical industry

In the pharmaceutical industry, SAXS analysis contributes to the understanding of drug formulations, polymorphism, and drug-delivery systems. It aids in optimizing drug stability, solubility, and bioavailability, all crucial factors in pharmaceutical development. SAXS is particularly valuable in the formulation of amorphous drugs and the study of protein-ligand interactions.

How does SAXS work?

SAXS operates by exposing a sample to X-ray radiation and measuring the scattered X-rays at small angles, typically below 10 degrees. The resulting scattering pattern is analyzed to extract information about the spatial arrangement of structures within the sample. The intensity and distribution of scattered X-rays provide details about the size, shape, and internal organization of the nanoscale structures in the size range of 1-100 nm.

SAXS and WAXS

SAXS and wide-angle X-ray scattering (WAXS) are complementary techniques often used together to obtain a comprehensive understanding of a material's structure in the atomic to nanoscale. In WAXS, X-rays scatter at wider angles and are detected to obtain information on sample structure in sub-nanoscale (<1 nm). Therefore, WAXS allows for the characterization of atomic and molecular arrangements by obtaining information on the atomic scale.

Advantages and limitations of SAXS analysis

Compared to other methods, such as electron microscopy (scanning and transmission in combination with FIB and BIB preparation) and small angle neutron scattering (SANS), SAXS offers advantages in terms of suitability for a more diverse range of sample matrices with minimal sample preparation. Although SANS is also a non-destructive analysis like SAXS, it requires a neutron source from a reactor or spallation facility, whereas SAXS is nowadays accessible on the laboratory scale.

In terms of limitations, SAXS data often requires modeling and interpretation, which can make it challenging to deconvolute overlapping signals from different components in complex systems. This can limit the method's ability to distinguish fine structural details.