Structure of e-beam sculptured poly(N-vinylpyrrolidone) networks across different length-scales, from macro to nano

Study of macromolecular structure and dynamics of networks formed by pulsed electron-beam irradiation of poly(N-vinyl pyrrolidone) (PVP) aqueous solutions, at relatively low energy per pulse and across different concentration regimes, provides the basis for the understanding of a new generation of functional nanostructures. Networks are the result of the follow-up reactions initiated by a continuous series of electron pulse-generated hydroxyl radicals, which may have a different fate at the variance of polymer concentration. Different spectroscopic techniques, FT-IR, C-13 {H-1} CP-MAS NMR and Raman, applied to characterize the formed networks, describe a profound modification of the chemical structure when network size is approaching the nanoscale. Static light scattering measurements provide further information on the average weight molecular weight modification of PVP when forming nanogel particles. From the simultaneous control of network size and modification of chemical functionality stems also an intrinsic fluorescence of these nanogels never observed before. Altogether the obtained radiation-sculptured nanogels exhibit interesting multifunctionality that, coupled with the already proven biocompatibility, can be exploited in the biomedical field. (C) 2012 Elsevier Ltd. All rights reserved.