The burgeoning interest in biopolymer 3D printing arises from its capacity to meticulously engineer tailored, intricate structures, driven by the intrinsic benefits of biopolymers—renewability, chemical functionality, and biosafety. Nevertheless, the accessibility of economical and versatile 3D-printable biopolymer-based inks remains highly constrained. This study introduces an electroconductive ink for direct-ink-writing (DIW) 3D printing, distinguished by its straightforward preparation and commendable printability and material properties. The ink relies on chitosan as a binder, carbon fibers (CF) a low-cost electroactive filler, and silk fibroin (SF) a structural stabilizer. Freeform 3D printing manifests designated patterns of electroconductive strips embedded in an elastomer, actualizing effective strain sensors. The ink's high printability is demonstrated by printing complex geometries with porous, hollow, and overhanging structures without chemical or photoinitiated reactions or support baths. The composite is lightweight (density 0.29 ± 0.01 g/cm), electroconductive (2.64 ± 0.06 S/cm), and inexpensive (20 USD/kg), with tensile strength of 20.77 ± 0.60 MPa and Young's modulus of 3.92 ± 0.06 GPa. 3D-printed structures exhibited outstanding electromagnetic interference (EMI) shielding effectiveness of 30–31 dB, with shielding of >99.9 % incident electromagnetic waves, showcasing significant electronic application potential. Thus, this study presents a novel, easily prepared, and highly effective biopolymer-based ink poised to advance the landscape of 3D printing technologies.

中文翻译：

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基于壳聚糖的导电墨水，无需化学反应，可用于电磁干扰 (EMI) 屏蔽和应变传感应用的经济高效且多功能的 3D 打印

人们对生物聚合物 3D 打印的兴趣日益浓厚，源于其精心设计定制的复杂结构的能力，而生物聚合物的内在优势（可再生性、化学功能性和生物安全性）推动了这种技术的发展。然而，经济且多功能的可 3D 打印生物聚合物墨水的可及性仍然受到高度限制。本研究介绍了一种用于直接墨水书写 (DIW) 3D 打印的导电墨水，其特点是其制备简单、可打印性和材料性能值得称赞。该墨水依靠壳聚糖作为粘合剂，碳纤维（CF）作为低成本电活性填料，丝素蛋白（SF）作为结构稳定剂。自由形式 3D 打印显示嵌入弹性体中的导电条的指定图案，从而实现有效的应变传感器。该油墨的高印刷适性通过印刷具有多孔、中空和悬垂结构的复杂几何形状而得到证明，无需化学或光引发反应或支持浴。该复合材料重量轻（密度0.29±0.01g/cm）、导电（2.64±0.06S/cm）且价格便宜（20美元/kg），拉伸强度为20.77±0.60MPa，杨氏模量为3.92±0.06GPa。 3D 打印结构表现出 30-31 dB 的出色电磁干扰 (EMI) 屏蔽效能，屏蔽 >99.9% 的入射电磁波，展现出巨大的电子应用潜力。因此，这项研究提出了一种新颖、易于制备且高效的生物聚合物墨水，有望推动 3D 打印技术的发展。