• yolk–shell particles;
  • small-angle scattering;
  • scattering functions

The single-particle small-angle scattering properties of the yolk–shell particle, a new type of core–shell particle with a mobile core within the hosting shell, are systematically investigated. The Debye spatial autocorrelation function, pair distance distribution function and intraparticle structure factor (form factor) are calculated and compared with the corresponding scattering functions of reference systems of hard sphere and concentric core–shell particles with identical sizes. On the basis of these theoretical calculations, it is found that the broken centrosymmetry, originating from the mobility of the trapped yolk, results in an imaginary scattering amplitude. As a result, it contributes an additional destructive interference term which smears certain features present in the scattering functions of the reference systems. These theoretical models raise the prospect of jointly using small-angle neutron and X-ray scattering techniques to quantitatively determine the structural characteristics of yolk–shell particles.