Droplets abound in nature and technology. In general, they are multicomponent, and, when out of equilibrium, have gradients in concentration, implying flow and mass transport. Moreover, phase transitions can occur, in the form of evaporation, solidification, dissolution or nucleation of a new phase. The droplets and their surrounding liquid can be binary, ternary or contain even more components, with several in different phases. Since the early 2000s, rapid advances in experimental and numerical fluid dynamical techniques have enabled major progress in our understanding of the physicochemical hydrodynamics of such droplets, further narrowing the gap from fluid dynamics to chemical engineering and colloid and interfacial science, arriving at a quantitative understanding of multicomponent and multiphase droplet systems far from equilibrium, and aiming towards a one-to-one comparison between experiments and theory or numerics. This Perspective discusses examples of the physicochemical hydrodynamics of droplet systems far from equilibrium and the relevance of such systems for applications.

自然和技术上的水滴比比皆是。通常，它们是多组分的，当不平衡时，浓度会发生梯度，这意味着流量和质量传递。此外，可以以新相的蒸发，固化，溶解或成核的形式发生相变。液滴及其周围的液体可以是二元，三元的，也可以包含更多的成分，其中某些成分处于不同的相。自2000年代初以来，实验和数值流体动力学技术的飞速发展使我们对此类液滴的物理化学流体力学的理解有了重大进展，从而进一步缩小了从流体动力学到化学工程，胶体和界面科学的差距，从而获得了定量的认识。远离平衡的多组分和多相液滴系统 并致力于实验与理论或数值之间的一对一比较。该观点讨论了液滴系统远离平衡状态的物理化学流体力学实例，以及此类系统在应用中的相关性。