Pragya Akanksha, Ghosh Tushar K
Fiber and Polymer Science Program Department of Textile Engineering Chemistry and Science Wilson College of Textiles North Carolina State University Raleigh NC 27606 USA.
Small Sci. 2025 May 20;5(8):2500234. doi: 10.1002/smsc.202500234. eCollection 2025 Aug.
Soft-to-hard material interfaces found in multimaterial systems, such as microelectronics, prosthetics, body armor, and soft robotics, often suffer from mechanical mismatches that compromise their structural integrity overtime. These mismatches occur due to significant differences in mechanical properties, such as stiffness, between soft materials (e.g., polymers and biological tissues) and hard materials (e.g., metals and ceramics). In this study, an extrusion-based approach is presented to fabricate continuous stiffness gradient materials using polydimethylsiloxane and thermoplastic expandable microspheres (EM). Morphological characterization shows the intended distribution of EM content along the length of the filament and the corresponding variation in tensile and bending stiffness. The gradient mechanical properties can be tuned by varying the EM expansion temperature. Compared to traditional fabrication techniques, this method allows for precise control over gradient magnitude and span, even post-fabrication, offering greater flexibility for various applications. This work demonstrates a scalable and efficient solution for mitigating the mechanical mismatch at soft-hard material junctions, offering the potential for advanced material design in both industrial and biomedical applications.
在多材料系统（如微电子、假肢、防弹衣和软体机器人）中发现的软-硬材料界面，常常会因机械不匹配而受损，随着时间的推移，其结构完整性会受到影响。这些不匹配是由于软材料（如聚合物和生物组织）与硬材料（如金属和陶瓷）之间在机械性能（如刚度）上存在显著差异而产生的。在本研究中，提出了一种基于挤出的方法，使用聚二甲基硅氧烷和热塑性可膨胀微球（EM）来制造连续刚度梯度材料。形态学表征显示了EM含量沿长丝长度的预期分布以及拉伸和弯曲刚度的相应变化。梯度机械性能可以通过改变EM膨胀温度来调节。与传统制造技术相比，该方法即使在制造后也能精确控制梯度大小和范围，为各种应用提供了更大的灵活性。这项工作展示了一种可扩展且高效的解决方案，用于减轻软硬材料交界处的机械不匹配，为工业和生物医学应用中的先进材料设计提供了潜力。
