在复杂流体中，化学试剂、固体颗粒、气泡、液滴和固体表面间的相互作用在许多工程过程中起着至关重要的作用，如泡沫浮选、乳液和泡沫形成、吸附、污垢、防污现象等。这些在分子、纳米和微观尺度上的相互作用显著地影响并决定了相关工程过程的宏观性能和效率。理解工程过程中的分子间和表面间相互作用具有基础和实际意义，这不仅改善了生产技术，而且为新材料的开发提供了有价值的见解。本文首先介绍了各种工程过程中涉及的典型分子间和表面间相互作用，包括Derjaguin-Landau-Verwey-Overbeek（DLVO）相互作用（即范德华相互作用和双电层相互作用）和非DLVO相互作用（如空间位阻和疏水相互作用）。本文简要介绍了用于测量复杂流体中分子间和表面间相互作用力的原子力显微镜和表面力仪等纳米力学技术；综述了近年来我们对矿物浮选、石油工程、废水处理、储能材料这些工程体系中分子间和表面间相互作用的研究进展；讨论了这些基本相互作用机制与解决工程挑战中的实际应用之间的相关性，并对未来的研究领域进行前景展望。

Interactions involving chemical reagents, solid particles, gas bubbles, liquid droplets, and solid surfaces in complex fluids play a vital role in many engineering processes, such as froth flotation, emulsion and foam formation, adsorption, and fouling and anti-fouling phenomena. These interactions at the molecular, nano-, and micro scale significantly influence and determine the macroscopic performance and efficiency of related engineering processes. Understanding the intermolecular and surface interactions in engineering processes is of both fundamental and practical importance, which not only improves production technologies, but also provides valuable insights into the development of new materials. In this review, the typical intermolecular and surface interactions involved in various engineering processes, including Derjaguin–Landau–Verwey–Overbeek (DLVO) interactions (i.e., van der Waals and electrical doublelayer interactions) and non-DLVO interactions, such as steric and hydrophobic interactions, are first introduced. Nanomechanical techniques such as atomic force microscopy and surface forces apparatus for quantifying the interaction forces of molecules and surfaces in complex fluids are briefly introduced. Our recent progress on characterizing the intermolecular and surface interactions in several engineering systems are reviewed, including mineral flotation, petroleum engineering, wastewater treatment, and energy storage materials. The correlation of these fundamental interaction mechanisms with practical applications in resolving engineering challenges and the perspectives of the research field have also been discussed.