Swellable poly(ionic liquid)s (SPILs) are ionic polymers featured ionic liquid repeating units in the backbone, exhibiting unique swelling ability to many solvents. SPILs can absorb solvents into a swollen state, accompanied by obvious weight/volume increase, color change, and the formation of internal porous structure. Their swelling ability depends on the compatibility of polymer chains with solvent molecules, and dissociation of ionic groups in solvents. Compared to non-swellable poly(ionic liquid)s, the good affinity for solvents endows SPILs with distinctive physicochemical properties, and these properties make SPILs particularly promising materials for various applications. This review offers a thorough understanding of the relationship between structure with swelling ability and describes the primary applications of SPILs. After introducing the chemical structures of ionic liquid monomers and crosslinkers as SPIL precursors, the synthetic strategies for SPILs with high swelling ability are discussed. Besides, the effects of different cations, anions and crosslinkers on the swelling ability are summarized. Applications of SPILs as catalysts, actuators, sensors, absorbents and separation membranes are highlighted. And challenges and opportunities in future research on this topic are prospected. This review aims to illustrate the swelling behavior of SPILs, also to help design SPILs with ideal swelling ability in target solvents to accommodate the growing practical needs.

可溶胀的聚（离子液体）（SPIL）是离子聚合物，其骨架中具有离子液体重复单元，对许多溶剂表现出独特的溶胀能力。SPILs可以吸收溶剂进入溶胀状态，伴随着明显的重量/体积增加、颜色变化和内部多孔结构的形成。它们的溶胀能力取决于聚合物链与溶剂分子的相容性，以及离子基团在溶剂中的解离。与不可溶胀的聚（离子液体）相比，对溶剂的良好亲和力赋予了SPILs独特的物理化学性质，这些性质使SPILs在各种应用中成为特别有前途的材料。这篇综述提供了对结构与膨胀能力之间关系的透彻理解，并描述了 SPIL 的主要应用。在介绍了离子液体单体和交联剂作为 SPIL 前体的化学结构后，讨论了具有高溶胀能力的 SPIL 的合成策略。此外，总结了不同的阳离子、阴离子和交联剂对溶胀能力的影响。重点介绍了 SPIL 作为催化剂、致动器、传感器、吸收剂和分离膜的应用。并展望了该课题未来研究中的挑战和机遇。本综述旨在说明 SPIL 的溶胀行为，同时帮助设计在目标溶剂中具有理想溶胀能力的 SPIL，以适应日益增长的实际需求。总结了不同阳离子、阴离子和交联剂对溶胀能力的影响。重点介绍了 SPIL 作为催化剂、致动器、传感器、吸收剂和分离膜的应用。并展望了该课题未来研究中的挑战和机遇。本综述旨在说明 SPIL 的溶胀行为，同时帮助设计在目标溶剂中具有理想溶胀能力的 SPIL，以适应日益增长的实际需求。总结了不同阳离子、阴离子和交联剂对溶胀能力的影响。重点介绍了 SPIL 作为催化剂、致动器、传感器、吸收剂和分离膜的应用。并展望了该课题未来研究中的挑战和机遇。本综述旨在说明 SPIL 的溶胀行为，同时帮助设计在目标溶剂中具有理想溶胀能力的 SPIL，以适应日益增长的实际需求。