Additive-free synthesis of poly(n-vinyl pyrrolidone) and poly(n-isopropylacrylamide) nanogels with controlled sizes.

An easy method is proposed to prepare poly(vinyl pyrrolidone) (PVP) and poly(N-isopropylacrylamide) (PNiPAAm) nanogels with sizes less than 100 nm. The underlying principle is to prepare dilute polymer solutions in acetone/water mixtures where acetone acts to break tridimensional structure of water hence disrupting the H-bonds bridging polymer coils causing separation and shrinkage in their sizes. Irradiation of these solutions by gamma-rays directly leads to the formation of intramolecular crosslinks within the coils resulting with nanogels with sizes smaller than precursor coils.

Green and Facile Synthesis of Pullulan-Stabilized Silver and Gold Nanoparticles for the Inhibition of Quorum Sensing.

Pullulan (Pull) decorated with monodisperse Ag and Au nanoparticles (NPs) was synthesized by a simple and green method. Samples were characterized by FTIR, UV-vis, NMR, XRD, TGA, SEM, XPS, DLS, and TEM. SEM images showed highly oriented microforms reported for the first time for Pull, because of the supramolecular self-assembling behavior of Pull chains.