Table 3.

Adjustable process parameters of cryogel synthesis and their effects on cryogel features [8,9].

Parameter	Effect	References
Polymer content/ polymer molecular weight	Gel solutions of lower molecular weight polymers result in the formation of larger pores compared to gel solutions of larger molecular weight polymers. Solutions of higher polymer concentration give a smaller average pore size.	[72,73,74,75]
Crosslinking	Affecting both the stiffness of the cryogel and also the degree of swelling, which in turn impacts on the elastic and mechanical properties. Physical crosslinking: Normally, cryogels with small pore sizes (<100 µm) are formed, and their mechanical strength is inversely correlated with the thawing rate—takes place during the thawing stage. Chemical crosslinking: Commonly larger pore size (>100 µm), improving mechanical stability—occurs during the storage of the solution at the given temperature.	[8,9,76,77]
Cryo-concentration (reaction constituents)	Decreasing the cryo-concentration lowers the critical concentration required for gelling. Increased cryo-concentration increases elasticity	[78]
Cryogelation temperature	Lowering the cryogelation temperature leads to smaller pores, and to thinner and smaller pore walls	[79,80,81,82]
Cooling rate	If the rate of crosslinking proceeds slower than the solvent crystallization, polymerization will generate cryogels of larger pore size; preparation of aligned pore structures	[46,83,84,85,86]
Charge density	Increasing the charge density results in a decreased pore size	[10]