Particle size distribution from small‐angle scattering data: A histogram technique

1987 ◽  
Vol 61 (4) ◽  
pp. 1348-1354 ◽  
Author(s):  
R. B. Stephens
2014 ◽  
Vol 47 (2) ◽  
pp. 642-653 ◽  
Author(s):  
Olexandr V. Tomchuk ◽  
Leonid A. Bulavin ◽  
Viktor L. Aksenov ◽  
Vasil M. Garamus ◽  
Oleksandr I. Ivankov ◽  
...  

Particles with a diffusive surface, characterized by a deviation from the Porod power-law asymptotic behavior in small-angle scattering towards an exponent below −4, are considered with respect to the polydispersity problem. The case of low diffusivity is emphasized, which allows the description of the scattering length density distribution within spherically isotropic particles in terms of a continuous profile. This significantly simplifies the analysis of the particle-size distribution function, as well as the change in the scattering invariants under contrast variation. The effect of the solvent scattering contribution on the apparent exponent value in power-law-type scattering and related restrictions in the analysis of the scattering curves are discussed. The principal features and possibilities of the developed approach are illustrated in the treatment of experimental small-angle neutron scattering data from liquid dispersions of detonation nanodiamond. The obtained scattering length density profile of the particles fits well with a transition of the diamond states of carbon inside the crystallites to graphite-like states at the surface, and it is possible to combine the diffusive properties of the surface with the experimental shift of the mean scattering length density of the particles compared with that of pure diamond. The moments of the particle-size distribution are derived and analyzed in terms of the lognormal approximation.


2007 ◽  
Vol 22 (7) ◽  
pp. 1907-1920 ◽  
Author(s):  
Joseph T. Mang ◽  
Rex P. Hjelm ◽  
Steven F. Son ◽  
Paul D. Peterson ◽  
Betty S. Jorgensen

Small-angle scattering (SAS) and ultra small-angle scattering techniques, employing x-rays and neutrons, were used to characterize six different aluminum nanopowders and nanopowders composed of molybdenum trioxide and tungsten trioxide nanoparticles. Each material has different primary particle morphology and aggregate and agglomerate geometry, and each is important to the development of nano-energetic materials. The combination of small-angle and ultra small-angle techniques allowed a wide range of length scales to be probed, providing a more complete characterization of the materials. For the aluminum-based materials, differences in the scattering of x-rays and neutrons from aluminum and aluminum oxide provided sensitivity to the metal core and metal oxide shell structure of the primary nanoparticles. Small-angle scattering was able to discriminate between particle size and shape and agglomerate and aggregate geometry, allowing analysis of both aspects of the structure. Using the results of these analyses and guided by scanning electron microscopy (SEM) images, physical models were developed, allowing for a quantitative determination of particle morphology, mean nanoparticle size, nanoparticle size distribution, surface layer thickness, and aggregate and agglomerate fractal dimension. Particle size distributions calculated using a maximum entropy algorithm or by assuming a log-normal particle size distribution function were comparable. Surface area and density determinations from the small-angle scattering measurements were comparable to those obtained from other, more commonly used analytical techniques: gas sorption using Brunauer–Emmett–Teller analysis, thermogravimetric analysis, and helium pycnometry. Particle size distribution functions derived from the SAS measurements agreed well with those obtained from SEM.


2021 ◽  
Vol 54 (5) ◽  
Author(s):  
Debasis Sen ◽  
Ashwani Kumar ◽  
Avik Das ◽  
Jitendra Bahadur

A new method to estimate the size distribution of non-interacting colloidal particles from small-angle scattering data is presented. The method demonstrates that the distribution can be efficiently retrieved through features of the scattering data when plotted in the Porod representation, thus avoiding the standard fitting procedure of nonlinear least squares. The present approach is elaborated using log-normal and Weibull distributions. The method can differentiate whether the distribution actually follows the functionality of either of these two distributions, unlike the standard fitting procedure which requires a prior assumption of the functionality of the distribution. After validation with various simulated scattering profiles, the formalism is used to estimate the size distribution from experimental small-angle X-ray scattering data from two different dilute dispersions of silica. At present the method is limited to monomodal distributions of dilute spherical particles only.


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