Chumachenko V. Branched water soluble polymers for metal contained nanosystems fabrication.

Current thesis devoted to synthesis and study branched graft copolymers Dextran Polyacrylamide (D-PАА) and Dextran-N-isopropylacrylamide (D-PNIPAM) of various macromolecular structure and nanosystems based on ones with metal nanoparticles as well as their application for targeted drug delivery. Gel chromatography was used to study the influence of molecular architecture of D-PАА and D-PNIPAM on its macromolecular characteristics. DLS method allowed to study the influence of macromolecular structure on the lower critical solution temperature (LCST). Various reductants included "green" reagents were used for Ag NPs synthesis. It allowed to produce silver nanoparticles of various size and shape. Microscopic and spectroscopic methods were used for nanoparticle characterization It was show that the nature of reducing agent and polymer structure as well as another synthesis condition define properties of metal nanoparticles. Size and shape of nanoparticles were studied using various techniques (DLS, SAXS and UV-vis spectroscopy) Quantum dots based on CdS and Au/CdS stabilized by D-PAA were fabricated and studied. The influence of Ag and Au nanoparticles on the LCST of thermosensitive D-PNIPAM was studied. It was demonstrated that the chemical nature of polymer matrix (uncharged or charged) and the polymer internal structure affect the nanoparticles' actual control on the sol size characteristics and nanoparticle size distribution in the nanosystems. The analysis of the silver sols was performed using UV-vis spectroscopy, QELS, and SAXS. All methods used were in good agreement for the characterization of size distribution of small particles (less than 60 nm) in the sols. The polydispersity estimated by various methods was comparable. It was shown that for precise analysis of sols synthesized in polymer matrices all these techniques should be used simultaneously. It should be noted that nanoparticle aggregates and macromolecules of the polymer matrix can be characterized only by QELS. Due to the features of their molecular structure branched polymer systems are of interest not only for basic research, but they are promising new generation functional materials. Such polymers are characterized by a more compact structure and, as a result, by a higher local concentration of the functional groups as compared with their linear analogs of the similar molecular mass. The carried out studies have proved the efficiency of using branched polymers as matrices for the formation of silver NPs and their stabilization. It has been demonstrated that stable silver colloids could be synthesized in both nonionic and branched anionic matrices, meanwhile, the linear matrix in the anionic form does not stabilize the nanosystem. The extremely elongated (extended) and rigid conformation of the macromolecule of the branched polyelectrolyte matrix promotes the preparation of sols resistant to phase separations. We have demonstrated the differences in the nanosystems synthesized in nonionic and ionic branched polymer matrices, in particular, the differences in their size characteristics and during sol ageing processes. The metal/semiconductor (Au/CdS/D-g-PAA) nanocomposites were synthesized in the solution of branched D-g-PAA polymer. Polymer controlled the size and morphology of NPs in the process of their synthesis and was a stabilizing agent for sols. The nanosystems containing Au NPs or CdS separately were obtained for comparative studies.