Biermann Tobias, Mesecke Lennart, Teves Simon, Ziesche Ivo, Lachmayer Roland
Institute of Product Development, Leibniz University Hannover, An der Universität 1, 30823 Garbsen, Germany.
Cluster of Excellence PhoenixD, Leibniz University Hannover, Welfengarten 1A, 30167 Hannover, Germany.
Materials (Basel). 2025 Jul 3;18(13):3164. doi: 10.3390/ma18133164.
Embedded printing of soft materials relies on yield-stress support matrices to prevent sagging and enable freeform fabrication. The rheological parameters of the matrix material directly influence critical printing outcomes such as strand positioning, cavity formation, structural stability, and defect suppression in embedded printing. Despite widespread use of formulations, a systematic rheological characterization of across relevant polymer concentrations and pH levels for embedded printing is lacking. Here, we implement a full-factorial design with polymer concentrations from 0.1wt% to 0.9wt% and triethanolamine dosages of 30-50µL per 100g. Steady-shear (0.001-200s-1) and oscillatory (1Hz) rheometry yielded Herschel-Bulkley parameters τy, , as well as storage and loss modulus G'/G''. All formulations exhibited pronounced shear-thinning, with τy increasing nonlinearly from <1Pa to 41.1Pa and G' reaching ≈400Pa at 0.9wt%. A five-hour window of invariant rheology was identified, followed by a Δτy≈10Pa increase after five days, indicating delayed polymerization. The comprehensive material characterization defines a rheological window for and facilitates simulation-based modeling and the targeted tuning of matrix properties. Heatmaps provide an interpolated depiction of combined carbomer and triethanolamine concentrations, enabling tunable support matrices for embedded printing.
软材料的嵌入式打印依赖于屈服应力支撑基质来防止下垂并实现自由形式制造。基质材料的流变参数直接影响关键的打印结果，如丝的定位、空洞形成、结构稳定性以及嵌入式打印中的缺陷抑制。尽管配方被广泛使用，但缺乏针对嵌入式打印在相关聚合物浓度和pH水平下对其进行系统的流变学表征。在此，我们采用全因子设计，聚合物浓度范围为0.1wt%至0.9wt%，每100g三乙醇胺用量为30 - 50µL。稳态剪切（0.001 - 200s⁻¹）和振荡（1Hz）流变学得出了赫谢尔 - Bulkley参数τy、 、 ，以及储能模量和损耗模量G'/G''。所有配方都表现出明显的剪切变稀，τy从<1Pa非线性增加到41.1Pa，在0.9wt%时G'达到约400Pa。确定了一个五小时的流变学不变窗口，随后五天后Δτy增加约10Pa，表明聚合延迟。全面的材料表征定义了 的流变窗口，并有助于基于模拟的建模和基质性能的靶向调整。热图提供了卡波姆和三乙醇胺组合浓度的插值描述，可为嵌入式打印提供可调节的支撑基质。
