电流体雾化双液滴电聚结行为研究

Investigate on Double Droplets Electro-Coalescence by Electrospray Deposition(ESD)

电流体喷印技术具有分辨率高,溶液参数适应性广等优点,是新型显示制造工艺创新突破的重要载体之一,可用于OLED微米厚度有机TFE膜高效制造。为深入探索电流体雾化技术制备微纳液膜过程,解决现阶段对液膜制备过程中各因素作用机理了解不清的问题,基于相场方法建立了液滴电聚结两相流耦合模型,分析了制备过程中“双液滴电聚结”单元。研究外加电压、基板接触角、液滴间隙和直径对液滴聚结的影响,并总结了液滴可聚结工艺参数相图。研究结果表明,外加电压越大、液滴隙径比越小,聚结后液滴高径比越大,聚结越快;基板接触角越大,聚结后高径比越大,聚结越慢,甚至可能使液滴无法聚结。在亲水基板上外加适当电压或增加液滴密度缩短液滴间隙有助于促成基板上液滴电聚结.该研究结论和工艺相图可应用与电流体雾化制膜时工艺参数调控。

Electrohydrodynamic(EHD)printing technology has the advantages of high resolution and wide adaptability to solu-tions,which is one of the important carriers for innovative breakthroughs in new display manufacturing processes.In order to in-vestigate the preparation process of micro-nano liquid thin film by electrospray deposition(ESD)technology,and solve the prob-lem of unclear action mechanism of various factor in liquid thin film preparation process at this stage,a two-phase flow model of droplet electro-coalescence was established based on the phase field method,which analyzed the"double droplets electro-coalescence"unit in the thin film formation process.The effects of applied voltage,substrate contact angle,droplet interval and di-ameter on droplet coalescence were investigated and the allowing coalescence process parameters phase diagram of droplet was summarized.The results show that higher voltage and smaller droplet interval-to-diameter ratio lead to quicker coalescence and larger droplet height-diameter ratio after coalescence.The substrate contact angle increase will increase the height-to-diameter ratio after coalescence,slow the coalescence process and may even prevent the droplets from coalescing.Apply appropriate voltage or increase the droplet density to shorten the droplet interval will effectively promote the droplet electro-coalescence process on the hydrophilic substrate.The conclusion and process phase diagram can be used to control the process parameters in the preparation of thin film by ESD technology.