电纺直写微纳3D打印的构-效同步微能场调控机制研究

Electrohydrodynamic direct-writing (EDW) is one of the most promising micro/nano 3D printing technologies due to its excellent performance and great potential in micro/nano fabrication. A key aspect of EDW for micro/nano 3D printing is the synchronous control of precision forming and functional optimization during the process. This project aims at the development of one-step printing of micro/nano 3D structures, and local energy fields are introduced to investigate interference suppression and multi-scale control mechanism of charged EDW jet. Key scientific issues including multi-scale mechanical properties of EDW, simultaneous on-line control of jet solidification and vertical deposition, precise forming and cooperative functional optimization of micro/nano 3D structures are studied. The project is expected to: (1) elucidate the force and motion characteristics of a continuous jet in EDW process under the action of micro energy fields, and clarify the electrical and mechanical interferences between the structures; (2) reveal the multi-scale mechanical characteristics and control laws of vertical jet deposition, and realize the accurate overlay deposition; (3) expound the control laws of rheological characteristics, solidification speed and surface morphology of EDW jet, clarify the simultaneous control of jet solidification and 3D deposition, and reveal the structure-performance synchronous control mechanism of 3D depositional accuracy and functional enhancement. The results will enrich the control theories of micro energy field and fluidic/solid characteristics on micro/nano 3D printing, further consolidate the theoretical basis of micro/nano 3D printing, and provide new technological approaches for its industrial applications.

电纺直写微纳3D打印性能优异、应用潜力巨大，是最具前景的微纳3D打印技术之一，突破立体精确成型与复合功能优化同步调控已成为其应用研究的关键。项目针对微纳三维器件一步化喷印制造发展需求，引入微能场，研究射流干涉抑制与多尺度调控机理，围绕射流喷印多尺度力学特性、射流固化与叠加沉积同步在线调控、微纳三维结构精确成型与功能协同优化等关键科学问题展开研究。以期阐明微能场作用下电纺直写连续射流受力与运动特征，明确微结构间的电学与力学干涉；探明射流立体成型的多尺度力学特性和控制规律，实现图案化精确叠加沉积；揭示射流流变特性、固化速度及表面形貌的控制规律，掌握射流固化与三维成型同步控制方法，突破立体成型精度和复合功能提升的构-效同步调控机制。研究成果将丰富微纳3D打印微能场与流固特性调控理论，进一步巩固微纳三维喷印制造理论基础，并为其产业化应用提供新型技术途径。

作为一种新颖的微纳制造技术，电纺直写技术已在信息、生物医疗、航空等应用领域显现出强大的潜力。增强射流稳定性、提高喷印沉积精度、诱导纤维叠加沉积，是电纺直写技术应用于微纳3D打印的关键。引入辅助针尖构建外部聚焦电场，增强了对射流的引导与约束作用，从而克服射流螺旋鞭动、提高喷射稳定性，实现了电纺直写高精度图案化喷印与微纳三维结构叠加沉积。仿真分析了系统结构和工艺参数对聚焦电场的作用机制，优化电场聚焦电纺直写系统，进一步增强聚焦电场对射流的约束能力。实验研究了射流喷射沉积与流变行为的控制规律，通过减小施加电压、喷嘴至收集板距离、喷嘴内径有利于提高射流的稳定性。探索了电场聚焦电纺直写的喷印沉积规律。通过实验参数的匹配，实现了纤维稳定沉积，提高了沉积精度，完成纳米纤维的电场聚焦精确沉积控制，并成功实现复杂图案的喷印制造。聚焦电场加快了纤维中电荷的转移，有利于促进纤维的稳定叠加沉积，诱导图案化三维结构的直接喷印。通过改变喷嘴高度实现多种外形可控自螺旋微纳三维结构的制造。研究了工艺参数对三维结构叠加沉积行为的作用规律，成功喷印了多种图案化三维结构。明确了射流稳定沉积的电场聚焦控制方法，实现了直写纤维的高精度图案化喷印与微纳三维结构的可控叠加沉积，有利于促进电纺直写技术的产业化应用。