In-situ Synthesis And Photoelectric Properties Of Ag/PMMA Nanocomposites

Polymer-based nanocomposites is based on polymer as continuous phase, composed of nano-scale metal, semiconductor, rigid particles or other inorganic particles, fibers, carbon nanotubes as the dispersed phase, dispersed the modifier in the matrix materials uniformly by means of the proper preparation method, forming a complex system containing nanoscale materials. Due to the small size effect, large specific surface area, strong interface binding effect and objective quantum tunnel effect etc. of silver nanoparticles, nano-size silver can significantly improve the physical properties, mechanical properties, conductive properties and thermal conductivity etc. of polymer materials, thus, Ag/PMMA nanocomposite has widely potential application in defense and civil fields such as conductive films, optical filtering materials, photoelectric materials, ultra sensitive chemical biological sensors, catalytic dielectric materials and nano organic electrolytic. This article uses silver nitrate as the source of silver, N, N-dimethyl formamide (DMF) as the reducing agent and reaction solvent, polyvinyl pyrrolidone (PVP) as the stabilizer, prepares Ag/PMMA nanocomposite in PMMA matrix materials by high-temperature in-situ synthesis. The research focuses on studying the preparation methods of different nanometer Ag content and different particle size of materials respectively, and the influences and mechanism of material microstructure on its optical, electrical properties.First of all, selectes DMF boiling point temperature (156℃) as the reaction temperature, in-situ synthesis as the proper method, to prepare different nano Ag content and different particle size of the Ag/PMMA nanocomposite respectively by ontrolling the quality of PMMA and the sol reaction time, respectively. The results show that the existence of PVP successfully ensures the preparation of monodisperse Ag/PMMA nanocomposite;10wt.%-50wt.%nanometer Ag of Ag/PMMA nanocomposite can be obtained by controlling the quality of the PMMA in the reaction; particle size of Ag nanoparticles can be controlled by adjusting the reaction time, wherein nano Ag particle size can be controllable from1.89and20.83nm in the40wt.%Ag/PMMA nanocomposite. Secondly, research is done to clarify the affect and mechanism of the nano Ag content and particle size in PMMA on the conductive properties of Ag/PMMA nanocomposite. The results show that the adding of conductive Ag nanoparticles in PMMA can significantly improve the conductive ability of this material, when the Ag nanoparticles are in the conditions of good crystallinity, uniform particle size and homogeneous dispersion, the higher nano Ag content and smaller particle size result in the better conductive properties of the material, this conductive behavior can be well explained by the tunnel effect theory:nano-size silver acts as electronic transfer carrier and participates in conducting. The40wt.%Ag/PMMA nanocomposite of2.68nm particle size presents the best conductive properties, its resistivity is2.12x104Ω-cm.Finally, experiment is designed to expound the affects and mechanism of Ag/PMMA nanocomposite microstructure on its photo-response effect. Results show that the Ag/PMMA nanocomposites possesses stably recyclable photo-responsive effect. The surface plasmon resonance effect of Nano Ag is in response to the causes of the photo-responsive effect. Therefore, the content of nano-size Ag in the PMMA impacts the photo-response of the material less, but the particle size of silver is the key factor, under the same content of nano Ag, the smaller the Ag nanoparticles size, the more obvious effect of photo-responsive property is. When the nano Ag particle size in the40wt.%Ag/PMMA is2.68nm, the current under light is an order of magnitude smaller than current under dark.