From Nano to Macro: Thinking Bigger in Nanoparticle Assembly
From Nano to Macro: Thinking Bigger in Nanoparticle Assembly
复制标题
从纳米到宏观：纳米粒子组装的更大思考
DOI：
10.1021/acs.nanolett.1c02724
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发表时间：
2021
期刊：
影响因子：
10.8
通讯作者：
Macfarlane, Robert J.
中科院分区：
文献类型：
--
作者：
Macfarlane, Robert J.
在过去的几十年中，纳米粒子（NP）自组装已经发展到NP超晶格结晶可以被设想为用于制造功能器件和技术的可行方法的地步。[1 - 3]正如任何合成方法已经充分发展的新材料一样，现在出现了许多问题，必须解决这些问题才能使该领域取得进展。NP组装研究的下一阶段的两个问题在目前的文献中最常见（无论是隐含的还是明确的），可以说是“这些材料有什么新的特性？”和“这些超晶格有什么用" 4− 6当然，这些是将NP超晶格从实验室好奇心转变为有用材料的关键问题。然而，如果我们假设这些超晶格的性质和应用的识别是它们发展中唯一剩下的障碍，那么我们就有可能成为标准材料发展范式中一个关键盲点的受害者。具体来说，将材料从最初的合成或发现推进到其在功能应用中的使用，还需要我们回答“我们如何将这些材料加工成有用的形式？”的问题。未来对NP基材料的研究工作将依赖于以正确的几何构型生产它们的能力，因为除了纳米级有序之外的结构控制对于实现结构-性能关系的基础研究和有用器件的应用都很重要。最终，NP超晶格在推动科学和工程方面的影响力取决于我们在最初组装之外控制其层次结构的能力。宏观结构控制（例如，毫米级或更大）对NP超晶格的实用性具有明显的影响，因为器件或技术组件的最终形状因素决定了需要多少材料以及其整体形状需要是什么。处理超晶格的方式，不破坏所有的辛勤工作，使美丽的结晶几何形状不一定是一个简单的任务，虽然，作为最常见的材料处理技术设计的原子，分子和大分子系统并不总是与通常温和的条件下使用，以形成有序的NP阵列兼容。名义上，来自粒子组装的2D薄膜和涂层已经可以在厘米级或更大的尺度上开发，5，9 - 13，但通过NP自组装制造的保持纳米级有序的真正3D宏观物体更为罕见。[14 - 17]此外，即使在能够产生至少具有某些宏观尺寸的物体的组装方法中，对材料微观结构的操纵仍然不发达。微观结构特征是用于控制块体原子或分子材料的特性和行为的关键设计因素，包括机械（硬度、韧性、延展性）、化学（腐蚀和蚀刻、传输）和光学（光反射和散射）特性。因此，理解NP超晶格中的缺陷、晶粒尺寸或晶体织构等因素如何影响其性能是另一个关键的研究领域，这是由加工科学的创新所实现的。那么，我们如何建立这些NP超晶格的加工方法来操纵微观和宏观结构（而不牺牲纳米级组织），以及我们需要改进的各种NP组装技术的关键方面是什么？任何可加工的NP超晶格的明显标准之一是能够以适当的规模生产材料。
In the past few decades, nanoparticle (NP) self-assembly has advanced to the point that NP superlattice crystallization can be envisioned as a viable method for the fabrication of functional devices and technologies. 1− 3 As with any new material whose synthetic methods are sufficiently developed, multiple questions now arise that must be addressed to progress the field. The two questions for the next phase in NP assembly research most commonly found in the current literature (either implicitly or explicitly) could arguably be stated as “What new properties do these materials have?” and “What are these superlattices good for?”. 4− 6 Certainly, these are critical questions to transition NP superlattices from benchtop curiosities to useful materials. However, we run the risk of falling victim to a key blind spot in the standard materials development paradigm if we assume that the identification of properties and applications for these superlattices is the only hurdle remaining in their development. Specifically, advancing a material from its initial synthesis or discovery to its use in a functional application requires us to also answer the question of “How do we process these materials into a useful form?”. 7, 8 Future research efforts with NP-based materials are going to rely on the ability to produce them in the right geometric configuration, as structure control beyond just nanoscale ordering is important in enabling both fundamental investigations of structure− property relationships and application in useful devices. Ultimately, the amount of impact NP superlattices will have in advancing both science and engineering depends on how well we can control their hierarchical structures beyond just their initial assembly. Macroscopic structure control (eg, mm-scale or larger) has obvious implications for the utility of NP superlattices, as the final form factor of the device or technological component dictates both how much material is needed and what its overall shape needs to be. Processing the superlattices in a manner that does not disrupt all of the hard work spent making beautiful crystalline geometries is not necessarily a simple task, though, as most common material processing techniques designed for atomic, molecular, and macromolecular systems are not always compatible with the typically mild conditions used to form wellordered NP arrays. Nominally 2D films and coatings from particle assembly can already be developed on the centimeterscale or potentially larger, 5, 9− 13 but truly 3D macroscopic objects made via NP self-assembly that preserve nanoscale ordering are more rare. 14− 17 Moreover, even in assembly methods capable of generating objects with at least some macroscopic dimension, manipulation of material microstructure is still underdeveloped. Microstructural features are key design factors used to control the characteristics and behavior of bulk atomic or molecular materials including mechanical (hardness, toughness, ductility), chemical (corrosion and etching, transport), and optical (light reflection and scattering) properties. 7, 18 Understanding how factors like defects, grain sizes, or crystal texture in NP superlattices affect their performance is thus another critical area of investigation that is enabled by innovations in processing science. So how do we establish processing methods for these NP superlattices to manipulate both micro-and macroscopic structure (without sacrificing nanoscale organization), and what are the key aspects of our various NP assembly techniques that we need to improve upon to enable such research? One of the obvious criteria for any processable NP superlattice is the ability to produce materials at an appropriate scale …