Porogens and porogen selection in the preparation of porous polymer monoliths.

Porogens are key components required for the preparation of porous polymer monoliths for application in separation science. Porogens determine the stability, selectivity, and permeability of polymer monoliths. This review summarizes the role of porogens in the preparation of porous polymer monoliths with a focus on clear understanding of effect of porogens on morphological properties, porosity, surface area, mechanical stability, and permeability of monoliths, particularly targeting the field of separation science. This review also includes the use of different types of porogens with the focus on various approaches used to set criteria for their systematic selection, including porogen-free techniques recently used for synthesis of porous monoliths. It discusses the current state-of-the-art applications of porogens in column preparation as well as where the future developments in this field may be directed.