Islam Tanveer Ul, Gandhi Prasanna S
Suman Mashruwala Advanced Microengineering Laboratory, Department of Mechanical Engineering, Indian Institute of Technology Bombay, 400076, Powai, Mumbai, India.
Sci Rep. 2017 Nov 30;7(1):16602. doi: 10.1038/s41598-017-16830-3.
The pursuit of mimicking complex multiscale systems has been a tireless effort with many successes but a daunting task ahead. A new perspective to engineer complex cross-linked meshes and branched/tree-like structures at different scales is presented here. Control over Saffman-Taylor instability which otherwise randomly rearranges viscous fluid in a 'lifted Hele-Shaw cell' is proposed for the same. The proposed control employs multiple-ports or source-holes in this cell, to spontaneously shape a stretched fluid film into a network of well defined webs/meshes and ordered multiscale tree-like patterns. Use of multiple ports enables exercising strong control to fabricate such structures, in a robust and repeated fashion, which otherwise are completely non-characteristic to viscous fingering process. The proposed technique is capable of fabricating spontaneously families of wide variety of structures over micro and very large scale in a period of few seconds. Thus the proposed method forms a solid foundation to new pathways for engineering multiscale structures for several scientific applications including efficient gas exchange, heat transport, tissue engineering, organ-on-chip, and so on. Proposal of multi-port Hele-Shaw cell also opens new avenues for investigation of complex multiple finger interactions resulting in interesting fluid patterns.
对复杂多尺度系统的模仿追求一直是一项不懈的努力，虽已取得诸多成功，但前方仍有艰巨任务。本文提出了一种在不同尺度上设计复杂交联网格和分支/树状结构的新视角。为此，提出了对萨夫曼 - 泰勒不稳定性的控制方法，否则这种不稳定性会在“提升的赫勒 - 肖槽”中随机重新排列粘性流体。该提议的控制方法在这个槽中采用多个端口或源孔，以使拉伸的流体膜自发地形成定义明确的网/网格网络和有序的多尺度树状图案。使用多个端口能够以稳健且可重复的方式对制造此类结构进行强有力的控制，否则这些结构对于粘性指进过程来说是完全不典型的。所提议的技术能够在几秒钟内自发地制造出微观和非常大尺度上的各种结构族。因此，所提议的方法为工程多尺度结构的新途径奠定了坚实基础，可用于包括高效气体交换、热传输、组织工程、芯片器官等在内的多种科学应用。多端口赫勒 - 肖槽的提议也为研究导致有趣流体图案的复杂多指相互作用开辟了新途径。
