Easy monitoring, by flow FFF, of the behavior of nanoparticles formed from copolymers of sulfopropylmethacrylate and methylmethacrylate

The size and size distribution of nanoparticles are generally important for the characterization of these materials, but are particularly needed to determine their suitability for specific applications. When nanoparticles are obtained by micelle formation from synthetic copolymers their size and structure depend on the copolymer composition and charge. Minor changes in the macromolecule primary structure may lead to dramatic changes in the aggregation behavior, hence in the nanoparticle size and size distribution. While particle diameter may be accurately measured by various sizing methods, determination of the size distribution requires a methodology which combines an adequate resolving power with size measurement capabilities. Flow FFF has shown to be able to perform both tasks in a single run. Using a very small amount of sample it yields accurate size distribution curves of most various colloidal systems. For this reason it was used here for the analysis of two copolymers of sulfopropyl methacrylate and methylmethacrylate differing for the copolymerization process. Size analysis of these samples showed a dramatic difference in their capability of forming micellar aggregates as well as in the characteristic response to the solution ionic strength.