When does a polymer chain become a soft nanoparticle?

As the variety of nanoparticles increases, understanding the impact of particle deformability, morphology, and topology on its global properties becomes essential. With this in mind, we have synthesized soft polymeric nanoparticles ranging in crosslink densities of 0.1-10.7%. An interesting question arises with nanoparticles with such low crosslinking densities: at what point do these polymers transition from a molecule to a nanoparticle? Comprehensive analysis of small angle neutron scattering studies of these nanostructures in dilute solution provides structural characteristics that identify transitions from polymer chain-like behavior to particle-like behavior. These analyses include elucidating the Porod exponent in q-ranges that describe the interior structure of the nanoparticle, as well as analysis of dimensionless Kratky plots. These results show that PEHMA samples with crosslink density greater than ~ 0.81% present a particle like structure signified by a Porod exponent greater than 3, and clear presence of a peak in the Kratky plot. PS samples showed similar behavior, however a low molecular weight 0.81% crosslinking density sample exhibited clear chain-like characteristics suggesting that molecular weight may also influence morphological identity.