Studies on Zn based oxide nanoceramics for smart application

Abstract

This thesis deals with the development of Zn-based oxide nanoceramics for newlinesmart applications. The study broadly includes three major assignments; in the first newlinepart, a novel technique has been developed to synthesize morphology-controlled newlinepristine ZnO and Ni-doped ZnO nanoparticles via an inorganic-polymer hybrid newlineprecursor derived through a sol-gel type polymerization approach. The process newlineinvolves an amorphous Zn2+-(and/or Ni2+)-polymer precursor formed in a chemical newlinereaction between poly-vinyl alcohol (PVA)-sucrose and zinc and/or nickel salt newlinesolutions. The basic premise lies in the fact that PVA-sucrose polymeric structure newlinewith its and#150;OH headed groups offers adequate functionality to form complex structure newlinein small micelle, thereby, controls the nucleation and growth of nascent particles and newlineallow them to grow with specific morphologies according to the reaction conditions. newlineIn addition, the process immobilizes the immiscible inorganic constituent in the newlinepolymer micelles and favours the doping of Ni in the host ZnO matrix in a very newlinecontrolled way. In the second part, monodispersed ZnO:Ag core-shell nanoparticles newlinewere developed from the Zn2+-polymer precursor powders derived in the first part. newlineThe PVA polymeric layer in the processed powders acts as a cationic surfactant for newlinethe subsequent growth of Ag shell on ZnO. In another assignment, we explored newlineanother series of oxides, viz., Zn-doped Ni-ferrite nanoparticles (Ni1-xZnxFe2O4; newlinex=0.2-0.8) by using similar type of sol-gel process. As observed before, the PVA newlineessentially serves as a stabilizing medium with suitable reaction conditions newlinefavouring the formation of homogeneous Ni1-xZnxFe2O4 nanoparticles of controlled newlinemorphology. The structural, optical, electrical and magnetic properties of all the newlinesamples were evaluated in detail. newline