Synthesis of Nanoparticles in Silicate Matrix and Stimuli Responsive Nanocomposite Polymer Films

Interactions between aqueous metal ions and soluble silicates lead to the formation of insoluble metal silicate complexes that form nanoparticles via condensation polymerization. Metal silicates function as nanoreactors, effectively condensing metal ions into nano-sized particles that can undergo further chemical transformations. Core-shell nanostructures present an intriguing strategy for integrating materials with different properties. The silicate shell around the silver nanoparticles can be successfully infused with other metal ions, enabling subsequent reactions to tailor their properties. Silver nanoparticles exhibit strong interactions with light, surpassing other chromophores, including noble metal nanoparticles, due to their highly efficient surface plasmonic resonance. The unique optical properties of silver nanoparticles can be integrated with new functionalities by incorporating different materials into a single nanostructure, forming hybrid silver nanoparticles. The silicate shell around the silver nanoparticles can be utilized as a scaffold for complexing other metal ions, opening a possibility for the synthesis of different shells. Chapter 1 is more focused on metal silicate complex formation studies, and Chapter 2 explains the attempt to incorporate new materials via infusing metal ions into the silicate matrix, followed by further chemical reactions. Synthesizing a metal sulfide shell around the silver core to integrate semiconductor properties and plasmonic properties is challenging because the silicate layer is permeable to sulfide, and the Ag has a higher affinity to sulfide compared to most metals. The silver core is incorporated with CuS and ZnS using the proposed model, but the long-term stability of the hybrid nanoparticles needs to be addressed. Lanthanide ions are another important metal silicate iv forming group. Eu3+ has successfully been used to incorporate photoluminescence properties into AgNPs using the proposed model integrating both plasmonic and photoluminescence properties. Chapter 3 discusses polymer-based stimuli-responsive self-folding materials. Polymers can be doped with various species, such as metal ions, molecules, or nanoparticles, to develop stimuli-responsive, self-folding materials. Self-folding behavior can be achieved by generating differential responses to external stimuli due to the inhomogeneous properties within the polymer films. To address the delamination issues in bilayer polymer films, plasma and ozone oxidation treatments, as well as mechanical compression, were explored to enhance interlayer adhesion. Additionally, a novel approach was developed using homopolymer films, where only one side is selectively doped with various species. This method enables the fabrication of stable, stimuli-responsive, self-folding polymer films with improved structural integrity and performance.