Needle based droplet microfluidic synthesis of high thermal conductivity Ferrofluid microcapsules for thermal management
基于针式液滴微流控技术制备高热导率磁流体微胶囊及其在热管理的应用
Fei Long, Haocheng Wang, Bing Wang, Hongru Zheng, Jing Wang*, Yuchuan Cheng*, Yong Ren*
龙菲，Haocheng Wang，王兵，郑洪茹，王静*，程昱川*，任勇*
全文链接：https://www.sciencedirect.com/science/article/pii/S2352940725002987
Abstract
高效散热仍是先进热管理系统面临的关键挑战，尤其在高性能电子设备及高能耗应用中更为突出。本研究提出了一种新型热调节微胶囊，将磁流体的磁响应特性与聚合物壳层的结构稳定性和可调性相结合，展现出巨大的应用潜力。利用针式液滴微流控技术，成功将油基磁流体（OMF）封装于己二醇二丙烯酸酯（HDDA）壳层内，实现了微胶囊结构和尺寸的精确调控，所得微胶囊平均直径为 406.87 μm，尺寸变异系数低于 5%。热学性能表征结果表明，微胶囊的散热效率受其尺寸、环境温度及外加磁场强度（磁通密度）共同影响。在 300 mT 磁场作用下，其热导率可达 1.232 W/(m·K)，优于传统散热材料。力学测试显示其刚度具有磁场响应特性，在 300 mT 直流磁场下可提升至约 1 MPa，较无磁场条件下提高了3个数量级。此外，其在交变磁场下的光热效应证实了其将电磁能转换为热能的能力。在电子芯片冷却测试中，OMF-HDDA 微胶囊的散热性能较传统冷却剂提升了 36.86%。上述研究结果凸显了该微胶囊作为下一代高性能、环保型热管理解决方案的创新潜力。
Efficient heat dissipation remains a critical challenge in advanced thermal management systems, particularly in high-performance electronics and energy-intensive applications. This study presents a novel thermal regulation microcapsule that integrates the magnetic properties of the core material with the stability and tunability of the shell material, offering significant application potential. Using needle-based double emulsion microfluidics, oil magnetic fluid (OMF) was encapsulated within a hexanediol diacrylate (HDDA) shell, achieving precise structural and size control with an average diameter of 406.87 μm and size variation below 5%. Thermal characterization demonstrated that microcapsule heat dissipation efficiency depends on size, temperature, and magnetic flux density, with a thermal conductivity of 1.232 W/m·K under a 300 mT magnetic field, outperforming conventional materials. Mechanical testing revealed variable stiffness, reaching ∼1 MPa in a 300 mT direct current magnetic field, a thousandfold increase compared to non-magnetic conditions. Furthermore, photothermal effects under an alternating magnetic field confirmed their capacity for energy conversion via heat generation. In electronic chip cooling tests, OMF-HDDA microcapsules achieved a 36.86% enhancement in heat dissipation compared to traditional coolants. These findings highlight the microcapsules' innovative potential as a high-performance, environmentally friendly solution for next-generation thermal management systems.
