Abstract Additive printing techniques are regarded as revolutionary and versatile methods of advanced device manufacturing, stemming from the possibility to pattern materials on a custom-based approach and the potential to create novel microstructures and achieve new functionalities. Despite these advantages, the inherent anisotropy of the printing process is a source of property gradients within the printed materials, often associated with variable and/or poor performance. Up to date, the evolutionary pathways associated with printing have largely remained unaddressed, mainly owing to the difficulty to study the transformations induced in the material during processing. Time-resolved coherent X-ray scattering techniques, such as X-ray photon correlation spectroscopy, enable the in situ study of transient nanoscale and mesoscale states in a large variety of materials, including amorphous ones, by directly accessing the most relevant timescales and length scales of their nanoscale and mesoscale dynamics, self-assembly, and mesostructure evolution. We conduct in operando studies of continuous-flow direct writing with colloidal inks, focusing on how the ink formulation and ink-substrate interactions affect the processes that determine the macroscopic properties of the printed materials. We find fundamental differences in the ink structural relaxations emerging from the primary colloid properties (monodisperse versus aggregated colloids) and the substrates surface energy and mechanical properties. Our work helps to reveal and quantify the basic science governing the evolution of 3D-printed materials during processing, ultimately improving engineering criteria for the design of printable materials.

中文翻译：

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时间分辨相干 X 射线散射揭示 3D 打印过程中的油墨-基材相互作用

摘要 增材印刷技术被认为是先进设备制造的革命性和通用方法，源于基于定制方法对材料进行图案化的可能性以及创造新型微结构和实现新功能的潜力。尽管有这些优点，印刷过程固有的各向异性是印刷材料内性能梯度的来源，通常与可变和/或较差的性能有关。迄今为止，与印刷相关的进化途径在很大程度上仍未得到解决，主要是由于难以研究加工过程中材料中引起的转变。时间分辨相干 X 射线散射技术，例如 X 射线光子相关光谱，通过直接访问其纳米尺度和中尺度动力学、自组装和细观结构演化的最相关时间尺度和长度尺度，能够对包括非晶材料在内的多种材料的瞬态纳米尺度和中尺度状态进行原位研究。我们对胶体油墨的连续流动直接书写进行了操作研究，重点是油墨配方和油墨-基材相互作用如何影响决定印刷材料宏观特性的过程。我们发现主要胶体特性（单分散与聚集胶体）和基材表面能和机械特性引起的油墨结构松弛存在根本差异。