Ramon Alberto, Liashenko Ievgenii, Rosell-Llompart Joan, Cabot Andreu
Catalonia Institute for Energy Research (IREC), Jardins de les Dones de Negre 1, Sant Adrià de Besòs, 08930 Barcelona, Spain.
Department of Chemical Engineering, University Rovira i Virgili, Av. dels Països Catalans 26, 43007 Tarragona, Spain.
Nanomaterials (Basel). 2024 Jan 27;14(3):273. doi: 10.3390/nano14030273.
Electrohydrodynamic (EHD) jet printing of solvent-based inks or melts allows for the producing of polymeric fiber-based two- and three-dimensional structures with sub-micrometer features, with or without conductive nanoparticles or functional materials. While solvent-based inks possess great material versatility, the stability of the EHD jetting process using such inks remains a major challenge that must be overcome before this technology can be deployed beyond research laboratories. Herein, we study the parameters that affect the stability of the EHD jet printing of polyethylene oxide (PEO) patterns using solvent-based inks. To gain insights into the evolution of the printing process, we simultaneously monitor the drop size, the jet ejection point, and the jet speed, determined by superimposing a periodic electrostatic deflection. We observe printing instabilities to be associated with changes in drop size and composition and in the jet's ejection point and speed, which are related to the evaporation of the solvent and the resulting drying of the drop surface. Thus, stabilizing the printing process and, particularly, the drop size and its surface composition require minimizing or controlling the solvent evaporation rate from the drop surface by using appropriate solvents and by controlling the printing ambient. For stable printing and improved jet stability, it is essential to use polymers with a high molecular weight and select solvents that slow down the surface drying of the droplets. Additionally, adjusting the needle voltages is crucial to prevent instabilities in the jet ejection mode. Although this study primarily utilized PEO, the general trends observed are applicable to other polymers that exhibit similar interactions between solvent and polymer.
基于溶剂的油墨或熔体的电流体动力学（EHD）喷射印刷能够制造具有亚微米特征的基于聚合物纤维的二维和三维结构，这些结构可含有或不含导电纳米颗粒或功能材料。虽然基于溶剂的油墨具有很大的材料通用性，但使用此类油墨的EHD喷射过程的稳定性仍然是一个重大挑战，在该技术能够在研究实验室之外得到应用之前，必须克服这一挑战。在此，我们研究了影响使用基于溶剂的油墨进行聚环氧乙烷（PEO）图案EHD喷射印刷稳定性的参数。为了深入了解印刷过程的演变，我们通过叠加周期性静电偏转来同时监测液滴尺寸、喷射点和喷射速度。我们观察到印刷不稳定性与液滴尺寸和组成的变化以及喷射点和速度的变化有关，这些变化与溶剂的蒸发以及由此导致的液滴表面干燥有关。因此，稳定印刷过程，特别是稳定液滴尺寸及其表面组成，需要通过使用合适的溶剂并控制印刷环境来最小化或控制液滴表面的溶剂蒸发速率。为了实现稳定印刷并提高喷射稳定性，使用高分子量聚合物并选择能够减缓液滴表面干燥的溶剂至关重要。此外，调整针电压对于防止喷射模式中的不稳定性至关重要。尽管本研究主要使用了PEO，但观察到的一般趋势适用于其他在溶剂和聚合物之间表现出类似相互作用的聚合物。
