MULTIMODAL PARTICLE-SIZE DISTRIBUTION OR FRACTAL SURFACE OF ACRYLIC-ACID COPOLYMER NANOPARTICLES - A SMALL-ANGLE X-RAY-SCATTERING STUDY USING DIRECT FOURIER AND INDIRECT MAXIMUM-ENTROPY METHODS

Acrylic acid copolymers are potential carriers for drug delivery. The surface, surface rugosity and the absolute dimension of the particles are parameters that determine the binding of drugs or detergents, diff usion phenomena at the surface and the distribution of the carrier wit hin the human body. The particle-size distribution and surface rugosit y of the particles have been investigated by small-angle X-ray scatter ing and dynamic light scattering. Direct Fourier transform as well as a new strategy for the indirect maximum-entropy method MAXENT are used for data evaluation. Scattering equivalence of a pure multimodal dist ribution of hard spheres (five populations) and a mixed multimodal-sur face-fractal model (four populations) was found. Model calculations an d dynamic light-scattering experiments gave evidence of the multimodal particle-size distribution combined with the fractal surface of the c arrier The main moiety consists of particles 90 nm in diameter which a re surface fractals in the 10 nm region.