Small-Angle X-ray Scattering (SAXS) is a very useful characterization technique.

Basically, there are four common x-rays based characterization techniques, i.e.,

1. XRD: X-rays diffraction, also called WAXS: Wide-angle X-ray scattering
2. GIXS: Grazing Incidence X-ray Scattering
3. XRF: X-Ray Fluorescence
4. SAXS: Small-Angle X-ray Scattering

Here, let's discuss Small-Angle X-ray Scattering (SAXS) in detail.

The SAXS is a technique to explore material structures at small angles or at large distances. Here, the data is interpreted by plotting the scattered X-rays intensity vs. the scattering angle.

*Applications and Uses*

This technique is immensely powerful to analyze solid objects, gels, powders, liquid dispersions, gaseous particles, aerosols, and micelles. The following parameters can be determined using the SAXS technique.

• Form factor
• Structure factor
• Nanoparticle’s size
• particle’s size distribution
• Shape of nanoparticle
• Surface structure
• Observe the reaction mechanism such as nucleation and growth of NPs
• Ostwald Ripening of NPs
• pore size distribution
• aggregation behavior

*Working principle of small angle x-ray scattering:*

The small angle x-ray scattering works on the transmission mode of geometry and is an indirect method using X-rays to generate a scattering pattern that is interpreted in the reciprocal space. In contrast, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and Atomic force microscopy (AFM), which are direct methods that produce an image in real space.

This technique uses the small angle approximation i.e., where the scattering angle 2θ is in Bragg’s equations is too small, generally less than 10° (~0 – 10°) and some others reported the angle from 0.1° to 5°.

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