Structures that are periodic on a microscale in three dimensions are abundant in nature, for example, in the cellular arrays that make up living tissue. Such structures can also be engineered, appearing in smart materials^1,2,3,4, photonic crystals⁵, chemical reactors⁶, and medical⁷ and biomimetic⁸ technologies. Here we report that fluid–fluid interfacial energy drives three-dimensional (3D) structure emergence in a micropillar scaffold. This finding offers a rapid and scalable way of transforming a simple pillar scaffold into an intricate 3D structure that is periodic on a microscale, comprising a solid microscaffold, a dispersed fluid and a continuous fluid. Structures generated with this technique exhibit a set of unique features, including a stationary internal liquid–liquid interface. Using this approach, we create structures with an internal liquid surface in a regime of interest for liquid–liquid catalysis. We also synthesize soft composites in solid, liquid and gas combinations that have previously not been shown, including actuator materials with temperature-tunable microscale pores. We further demonstrate the potential of this method for constructing 3D materials that mimic tissue with an unprecedented level of control, and for microencapsulating human cells at densities that address an unresolved challenge in cell therapy.

在三个维度上呈微尺度周期性的结构在自然界中很丰富，例如，在构成活组织的细胞阵列中。这种结构也可以设计，出现在智能材料^{1、2、3、4}、光子晶体⁵、化学反应器⁶、医疗⁷和仿生材料^8中技术。在这里，我们报告流体-流体界面能驱动微柱支架中的三维 (3D) 结构出现。这一发现提供了一种快速且可扩展的方法，将简单的支柱支架转变为复杂的 3D 结构，该结构在微观尺度上是周期性的，包括固体微支架、分散流体和连续流体。使用这种技术生成的结构具有一组独特的特征，包括固定的内部液-液界面。使用这种方法，我们在液-液催化感兴趣的状态下创建了具有内部液体表面的结构。我们还合成了以前从未展示过的固体、液体和气体组合的软复合材料，包括具有温度可调微孔的致动器材料。