Indirect Fourier Transform and Model Fitting of Small Angle Neutron Scattering from Silica Nanoparticles

Small angle neutron scattering (SANS) patterns from spheroidal silica nanoparticles (〈 D 〉 = 27.5 nm) dispersed in water at volume fractions ranging from 0.01 to 0.315 were interpreted using model fitting and indirect Fourier transform methods. By modeling the effective structure factor using a two‐Yukawa potential it was determined that the particles interact through weak long range attractive and shorter range repulsive inter‐particle forces. For weakly‐interacting particles (∼ 0.01 v/v) analysis of SANS patterns using a polydisperse spheres form factor is simple and accurate. However, we find that the indirect Fourier transform is a more robust method to calculate the radial distribution function for interacting particles over a broad range of particle concentrations.