Department of Electrical Engineering, University of Missouri, Columbia, MO 65211, USA.
Rep Prog Phys. 2013 Jun;76(6):066501. doi: 10.1088/0034-4885/76/6/066501. Epub 2013 May 30.
Nanotechnology is touted as the next logical sequence in technological evolution. This has led to a substantial surge in research activities pertaining to the development and fundamental understanding of processes and assembly at the nanoscale. Both top-down and bottom-up fabrication approaches may be used to realize a range of well-defined nanostructured materials with desirable physical and chemical attributes. Among these, the bottom-up self-assembly process offers the most realistic solution toward the fabrication of next-generation functional materials and devices. Here, we present a comprehensive review on the physical basis behind self-assembly and the processes reported in recent years to direct the assembly of nanoscale functional blocks into hierarchically ordered structures. This paper emphasizes assembly in the synthetic domain as well in the biological domain, underscoring the importance of biomimetic approaches toward novel materials. In particular, two important classes of directed self-assembly, namely, (i) self-assembly among nanoparticle-polymer systems and (ii) external field-guided assembly are highlighted. The spontaneous self-assembling behavior observed in nature that leads to complex, multifunctional, hierarchical structures within biological systems is also discussed in this review. Recent research undertaken to synthesize hierarchically assembled functional materials have underscored the need as well as the benefits harvested in synergistically combining top-down fabrication methods with bottom-up self-assembly.
纳米技术被誉为技术发展的下一个逻辑序列。这导致了与纳米尺度的开发和基础理解相关的研究活动的大量增加。自上而下和自下而上的制造方法都可用于实现一系列具有理想物理和化学特性的明确定义的纳米结构材料。在这些方法中，自下而上的自组装过程为制造下一代功能材料和器件提供了最现实的解决方案。在这里，我们全面回顾了自组装背后的物理基础以及近年来报道的指导纳米级功能块组装成分级有序结构的过程。本文强调了合成领域和生物领域的组装，强调了仿生方法在新型材料中的重要性。特别是，重点介绍了两种重要的定向自组装，即（i）纳米粒子-聚合物系统之间的自组装和（ii）外部场引导的组装。本文还讨论了在生物系统中观察到的导致复杂、多功能、分层结构的自然中自发的自组装行为。最近为合成分级组装功能材料所进行的研究强调了需要以及在协同结合自上而下的制造方法与自下而上的自组装方面所获得的益处。
