Beyond Water: The Solvent–Porogen Bottleneck in Natural-Product-Derived Cryopolymerization

Cryopolymerization creates interconnected macroporous networks by polymerizing a concentrated unfrozen phase while solvent crystals act as a transient porogen. Water is effective because ice crystallization templates the pores and concentrates reactive species, but this mechanism also imposes a solubility filter on monomer selection. This limitation matters for natural-product-derived materials: phenolics, terpenes, lignin-derived aromatics, and other bio-based scaffolds can be functionalized with polymerizable groups, yet many derivatives remain poorly soluble in water. Extending cryopolymerization beyond pure water is therefore a materials-design challenge, not simple solvent substitution. Candidate media may be neat solvents or mixtures, including aqueous–organic blends; each must dissolve the formulation and generate a crystalline phase at a temperature and timescale compatible with polymerization. A water/DMSO study shows that composition can shift a formulation from cryogelation to nonporous or phase-separated networks. We define this coupled solvation–crystallization constraint as the solvent–porogen bottleneck and outline a screening workflow based on phase behavior, polymerization kinetics, pore architecture, and solvent removal. Mapping this window could broaden the range of natural-product-derived monomers accessible to cryogels without assuming that one solvent will suit every chemistry or application.