The Preparation Of Silver Nanomaterials And Its Application In Conductive Ink

Silver nanomaterials have excellent electrical conductivity,thermal conductivity,bending resistance and good chemical stability,and are widely used in printed circuit boards,sensing,and wearable electronic devices.These properties of nano-silver mainly depend on its morphology,particle size,size distribution and dispersion stability.Therefore,the preparation of silver nanomaterials has become one of the hot spots in nanoscience research.At present,various shapes of nano-silver have been manufactured in large quantities.However,problems such as increased dispersion stability,lower purity,and more difficult to control quality have led to the fact that they cannot be effectively used in practical applications.Therefore,it is of great significance to explore high-quality preparation methods of silver nanomaterials and study their application in industrialization.This article focuses on the high-quality preparation of silver nanoparticles and silver nanowires and their application in conductive inks.The specific research content includes the following three parts:?1?We prepared silver nanoparticles by liquid phase chemical reduction method using self-made green environmental protection succinylated chitosan?SCS?as stabilizer,and glucuronic acid as reducing agent.The effects of the substitution degree and amount of SCS on the particle size and dispersion degree of nano-silver were explored.Meanwhile,the dispersion stability of nano-silver prepared by SCS was evaluated,and the stability mechanism was analyzed.The product was characterized by SEM,UV-vis,FT-IR,TGA,Malvern particle size analysis,etc.The monodisperse silver nano particles?25 nm?,which could be stored stably for one month without agglomeration and the surface organic matter?SCS?content was about 4.18%.Infrared analysis shows that the carboxyl and amide groups in the SCS molecule have complex coordination with the nano-silver,which promotes the SCS to adsorb on the surface of the silver particles,thereby stabilizing the silver nanoparticles and preventing the particles from agglomerating.Finally,based on the SCS stable system,the effects of reaction temperature,time and reactant concentration on the product particle size,size distribution and yield were also explored,and the best preparation process parameters of nanoparticles with small particle size,narrow distribution and high yield were obtained.?2?On the basis of the traditional polyol method,glycerol and diethylene glycol?DEG?are used as the solvent and reducing agent,PVP is selected as the surfactant,and Na Cl is used as the anion control agent to prepare the silver nanowires.The effects of volume ratio of polyol,molar ratio of PVP to Ag NO₃,molecular weight of PVP,Na Cl concentration,reaction temperature and time on product morphology and size were systematically investigated.SEM,UV-Vis,XRD,TGA,etc.showed that the resulting product was uniformly dispersed high-purity silver nanowires with almost no nanoparticles generated;the diameter of the silver wire was 35?50nm,the length was 8?12?m,and the aspect ratio can up to 300;the content of organic matter?PVP?on the surface of the nano-silver wire is about 3.9%.The experiment found that adjusting the volume ratio of glycerol and DEG can control the reduction rate of silver atoms and the migration rate of silver in the growth stage to control the silver line morphology.The introduction of an appropriate amount of DEG in the system is beneficial to improve the purity of silver nanowires and reduce the diameter of silver wires.When the volume ratio of glycerol to DEG is 1:1,the mass ratio of PVP?Mw=58000?to Ag NO₃ is 4:1,the concentration of sodium chloride is 10.2 m M,and the reaction can be achieved at 200?for 30 min,Fine and uniform high-quality silver nanowires can be acquired.?3?In order to investigate the application effect of the silver nanomaterial obtained in the above in specific practice,the silver nanoparticles and the silver nanowires are used as the conductive phase,and the appropriate amount of additives and solvents are added to configure the conductive ink and its dispersion stability was tested through the static solid content test;inks are coated on photo paper,we controll the sintering process and the ratio of conductive filler morphology and measure the square resistance value of the conductive ink coating;finally tearing and bending test of the coating to be explored for its mechanical properties in application.The results show that the conductive ink maintains good dispersion stability within 30 days without additional dispersant.At the same time,the sintering process and the mixed morphology?silver particles and silver wires?ratio have a significant impact on the conductivity of the ink layer.Among them,the mixed ink layer with a mass ratio of silver particles to silver wires of 1:3 is sintered at 120°C for 30 min,and the square resistance is as low as 0.88?,which is 1/17 of the square resistance of the silver nanoparticle conductive ink at the same quality.In addition,the mixed ink layer also has good quality durability and bending flexibility,and is expected to be used as a printed electronic materials in RFID radio frequency identification,smart wear,flexible sensing and other electronic fields.