Fundamental Research On CNTs Line Printing On PVA Substrate Based On Uniform Droplet Spraying

Due to its unique flexibility and ductility,flexible electronics have broad application prospects in fields of the information,the medical,the energy,and the defense.At present,the preparation process of the solid flexible substrate and the conductive pattern in the flexible electronic is separated,so that the volume,quality and the stability of performance of the product are not good.To solve this problem,this paper proposes a flexible electronic joint printing technology combining the carbon nanotube(CNTs)uniform droplet spraying technology and gel matrix micro-pen coating technology,which combine high-viscosity polymer coating and droplet deposition to realize the joint printing of PVA substrate and CNTs wire layer,which provides a direct,rapid and controllable molding of new method for the flexible electrons.There are no systematic studies reported because the many physical processes involve in the uniform droplet spraying of CNTs suspension,the controllable preparation of polymer film,the interaction between the PVA matrix and droplets of the containing CNTs suspension during uniform droplet spraying and micro-pen coating process.This paper aims to explore the dynamic infiltration behavior of the droplets containing CNTs suspension on the PVA matrix,reveal the effect of process parameters on the morphology of CNTs on the PVA gel matrix,obtain the stable printing parameters of CNTs line layer on PVA gel matrix to lay the foundation of the printing gel-based flexible electrons.The main research contents of this paper are as follows:(1)A multi-degree-of-freedom joint printing platform composed of a piezoelectric micro-nozzle,a micro-needle-coated needle,a stroboscopic camera,and a three-dimensional motion platform was developed,which can sequentially print on the same deposition platform of the gel matrix and the CNTs line layer,and simultaneously obtain the key parameters of the droplet spraying and micro-ply coating PVA substrate process.(2)The parameters that affect the stable of injection containing CNTs were determined.The stable printing of CNTs line layer is realized following by understanding the mechanism of the influence of pulse voltage amplitude and pulse width on the stable injection of CNTS droplets.Then,by comparing the evaporation self-assembly patterns of micro-lift droplets extruded by micro-pump and uniform skin-lift droplets injected by piezoelectric nozzle,it can be found that uniform droplet injection is more conducive to improving the uniformity of CNTs line layer.(3)The influence of forming process parameters on micro-ply-coated PVA film were studied.A micron-thickness PVA film is produced following by utilizing the influence of test parameters(i.e.working pressure,substrate speed and pen height)on the thickness of PVA polymer film were revealed.Then,the PVA matrix micro-pen coating forming with controlled thickness and internal quality was realized by using different inner diameter micro pens to coat the different widths of polymer film and exploring the influence of substrate temperature on the formation quality of PVA matrix.(4)The infiltration and spreading behavior of CNTs-containing droplets on PVA substrate were studied.The range of process parameters for stable deposition of CNTs on the PVA substrate were explored.The stable deposition of uniform CNTs line,coffee line and simple two-dimensional structure on the PVA substrate were realized,which lay a foundation for the preparation of gel-based flexible electrons.