Abstract Nanoparticle-based aerogels are one of the few examples of 3-dimensional nanoparticle assemblies that can achieve macroscopic sizes while fully retaining the size-specific properties of the initial nanobuilding blocks. A typical synthesis involves three main steps: i) Preparation of a stable dispersion containing all the building blocks with the desired composition, size, shape and crystallinity, ii) controlled destabilization of the dispersion into a gel, and iii) drying of the gels under preservation of the 3-dimensional nanoparticle architecture. In this review, we focus on the first two steps. We discuss the stability of colloidal dispersions, offering an overview of the different interparticle forces and how they can experimentally be modulated. In the next section, we discuss the gelation process in its entirety, including gelation mechanisms, and, most importantly, how it can rationally be controlled under consideration of the interparticle forces in the dispersion. Finally, the review concludes with an overview of the synthesis pathways to nanoparticle-based aerogels, divided into the gelation of sterically and charge-stabilized particles.

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从胶体分散体到气凝胶：如何掌握纳米粒子凝胶化

摘要 基于纳米颗粒的气凝胶是 3 维纳米颗粒组件的少数例子之一，它可以实现宏观尺寸，同时完全保留初始纳米构建块的尺寸特定特性。典型的合成包括三个主要步骤：i) 制备含有所有具有所需组成、尺寸、形状和结晶度的结构单元的稳定分散体，ii) 分散体受控去稳定化为凝胶，以及 iii) 凝胶的干燥保留 3 维纳米颗粒结构。在本次审查中，我们专注于前两个步骤。我们讨论了胶体分散体的稳定性，概述了不同的粒子间力以及它们如何通过实验进行调制。在下一节中，我们将全面讨论凝胶化过程，包括凝胶机制，以及最重要的是如何在考虑分散体中的粒子间力的情况下合理控制它。最后，综述总结了纳米颗粒气凝胶的合成途径，分为空间和电荷稳定颗粒的凝胶化。