Zinc oxide based polymer hybrid materials

• Zinkoxid-basierte Polymer-Hybrid-Materialien

Wilke, Philipp; Pich, Andrij (Thesis advisor); Klee, Doris (Thesis advisor)

Aachen : Publikationsserver der RWTH Aachen University (2015)
Dissertation / PhD Thesis

Aachen, Techn. Hochsch., Diss., 2015

Abstract

ZnO nanoparticles were successfully synthesized by a one-pot precipitation method and their surface modified by use of a fatty acid. It was shown that by switching the base amount between two different concentrations, two morphologies can be obtained, namely nanospheres and nanorods. ZnO nanorods showed improved colloidal stability in water and higher antibacterial activity compared to nanospheres. Further characterization revealed a double layer assembly of the surfactant-molecules on the nanoparticle’s surfaces. Moreover, the surfaces of the nanorods were successfully modified after reacting with a novel PEI-maltose compound. The synthesis of ZnO nanospheres was successfully transferred to the inside of a PVCL-based microgel system, i.e. the precipitation of ZnO occurred in the microgel network, as demonstrated by TEM, DLS and zetapotential measurements. Different PVCL-based microgels were tested concerning their use as ZnO hosts, including a microgel that was prepared using a novel macro monomer consisting of iso-Eugenol and poly(glycidole). The PVCL-itaconic acid and PVCL-iso-Eugenol systems show the most promising results within the framework of this thesis. Further on, novel PVCL-PEG microgels were synthesized under various conditions. DLS, zetapotential and calorimetric measurements revealed nanosized hydrogels; no turbidity was observed during the wet-chemical synthesis. These nanogels were successfully used for the in-situ conjugation of laser-generated nanoparticles, in cooperation with Essen University, by reproducing the synthesis during laser-ablation. The PVCL-itaconic acid and -PEG based microgels loaded with ZnO nanoparticles were further processed to obtain PCL microfibers by means of electrospinning. FESEM and TEM characterization proved the successful deposition of microgel-ZnO composites onto the PCL microfibers. Further studies showed that these novel three-component systems can release zinc ions and are non-toxic for human dermal fibroblasts.