Exploration On The Au Nanoparticle-based Eiectrophoretic Display

Gold nanoparticles have unique localized surface plamon resonance absorptionof light. The resonance absorption frequency and intensity of gold nanoparticles arelargely dependent on the refractive index of their environments; therefore, they have awide range of application such as sensing. However, there are rare reports about usinggold nanoparticles in display based on their refractive index sensitivity. In this thesis,the possibility of applying gold nanoparticles in electrophoretic display has beendiscussed. On the one hand, the method to imoblize gold nanoparticles on transparentsubstrate and fabricate gold nanoparticles-based color panel has been expored. Onethe other hand, the feasibility to use gold nanoparticles as highly stable colorant hasbeen also tested by using polyelectrolytes as capping ligand of gold nanoparticles.For the gold decorated transparent substrate, a facile and low cost self-assemblymethod has been applied.We use aminopropyltrimethoxysilane (APTMS) to modifythe ITO (or glass) substrates, then sodium citrate (or citric acid) capped goldnanoparticles are adsorbed on the substrate by weak intermolecular interactions, suchas static interactions and H bond interactions. The density of gold nanoparticles onsubstrates has been controlled by the pH and ionic strength of gold nanoparticles, andalso the adsorption time. The colour the transparent substrates can be improved byannealing at various temperatures.To apply the gold nanoparticles as mobile colorants, their stability and dispersityis very important. Gold nanoparticles with high stability and surface charge densityhave been synthesized using poly(diallyldimethylammonium chloride)(PDDA) ascapping ligand. Factors that influence on the synthesis of gold nanoparticles arediscussed in detail. The gold nanoparticles capped with other organic small moleculesare also prepared. The stability of the above gold nanopaticles in various solvents withhigh boiling points is invenstigated, and N-methyl pyrrolidone is chosen as thedispersing agent for electrophoresis taking advantages of its high chemical stability and it stabilizing effect for gold nanoparticles.The above work discusses and proves the feasibility of using gold nanoparticlesin electrophoretic display. The fabrication of the display devices based on this ideastill needs further extra work.