Influence Of Nano Tourmaline On Forming Conductive Silver By Inkjet 3D Printing

At present,nano silver materials are widely applied to flexible electronics products.As an additive manufacturing technology,inkjet 3D printing has various advantages,such as low cost,efficient and simple technical process,and has great potential in forming flexible electronics.However,present conductive silver ink prepared cannot meet higher and higher requirements because of their short storage time,unstable droplet morphology and poor conductive performance,which seriously affects the quality of flexible electronic products.Nano tourmaline has characteristics of excellent piezoelectricity,pyroelectricity and self-generation polarity.In this paper,conductive circuit are formed by inkjet 3D printing conductive nano tourmaline/silver ink.,the influence of nano tourmaline on rheological properties,droplet morphology of conductive silver ink as well as electrical conductivity of silver circuit,and the mechanism of nano tourmaline on the conductivity of silver circuit are thoroughly researched.The main work and innovations of this article are listed as follows:(1)Study the influence of additive amount of nano tourmaline on the Zeta potential,surface tension and viscosity of conductive silver ink.Nano tourmaline/conducting silver ink was prepared with nano silver particles as conductive phase,nano tourmaline as auxiliary agent,deionized water as solvent,and polyvinyl pyrrolidone as dispersant.The experimental results show that as the content of nano tourmaline increases,the p H value at the isoelectric point of the Zeta potential of the conductive silver ink will gradually decreases;the surface tension first decreases,and then tends to a stable value when the content of nano tourmaline exceeds 0.2 wt%;the viscosity value also decreases first,but when the content of nano tourmaline exceeds 0.2 wt%,the viscosity value increases.The properties of conductive silver ink with 0.2 wt% tourmaline are tested: surface tension is31.3 m N/m,viscosity is 9.7 m Pa · s,with high dispersion stability and long storage time.(2)Study the influence of nano tourmaline on ink droplet morphology and printed patterns.By optimizing the parameters of ink and printing,experiments of nano tourmaline/conductive silver ink were carried out.The experimental results show that the conductive silver ink can be ejected stably,when the piezoelectric pulse selects a trapezoidal wave with an amplitude of 90 V and adjusts the positive and negative pressures until a half-moon surface is formed at the nozzle.When using 0.2 wt% tourmaline conductive silver ink,the number of satellite is reduced,the tail is short and retracted quickly,stable ink droplets can be formed faster,and high-quality conductive silver circuit can be printed.(3)Study the influence of nano tourmaline content,sintering temperature and time on the phase composition,micro-morphology and conductivity of the silver circuit,and analyze the influence mechanism of nano tourmaline on the silver circuit conductivity.The experimental results show that: when the tourmaline content reaches 0.2 wt%,the electrical conductivity and compactness are the best,and the increasing tourmaline content will cause a decreasing trend of circuit quality.For the conductive silver ink added with 0.2 wt%tourmaline,after a heat treatment at 180 °C for 30 min,the conductive performance of printed conductive circuit is the best,and the lowest resistivity can reach 2.9 μΩ · cm.Through the research in this paper,it provides theoretical and experimental basis for forming high-conductivity silver circuit by inkjet 3D printing,and exhibits an important engineering practical significance in the flexible electronic additive manufacturing.