Cryo-concentration effect

The chosen solvent must crystallize rather than vitrify under the cryostracturing conditions otherwise, if the solvent imdergoes a glass transition, the unfrozen liquid microphase will not form and, hence, no cryo-concentrating effects will take place. This requirement is also valid for any other precursor system to be gelled cryogenic ally. 

The concentration of solutes or dispersed colloid-size particles is increased because of their expulsion into the volume of UFLMP as the solvent is crystallized. This cryo-concentration effect is one of the major factors responsible for the increase in the rate of the chemical reactions and intensification of intermolecular interactions inside the unfrozen inclusions, which act as microreactors. Provided the reactants are easily soluble compounds and are completely concentrated within the UFLMP, the concentrating extent at a certain negative temperature T can be estimated using the following formula [54] ... 

The cryo-concentration effect leads to increased concentrations of solutes within the UFLMP, facilitating the reaction efficiency. 

The initial concentration Co of the monomeric or the polymeric precursors is another important parameter in cryogel preparation. Due to the effect of cryo-concentration, cryogels can be prepared at much lower concentrations compared... 

Fonseca, R, Passot, S., Lieben, R, Marin, M. (2004). Collapse temperature of bacterial suspensions the effect of cell type and concentration. Cryo Letters, 25(6), 425-434. 

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