Temperature swelling switch

Do not try to open or repack polymeric columns. They are usually under some pressure and come out of the tube like toothpaste. The column is of no use. Polymeric columns are usually packed in one solvent, then switched to a second solvent, which causes the packing to swell and squeeze out voids. They are then designed to be run in the second solvent. Polymeric ion exchangers are usually run at elevated temperature. This serves two purposes it decreases mobile phase viscosity, thereby reducing operating pressures, and it speeds... 

Fig. 8.11, which shows the effect of temperature change on the swelling and deswelling of a hydrogel, resulting in an on-off switching mechanism. 

The mechanical properties of a gel are influenced by the degree of swelling. The volume phase transition and therefore the switching between two temperatures (above and below the temperature for volume phase transition) can be performed as a process under isobar or under isochoric conditions. For PNIPAAm, the bulk modulus shows a strong increase at 33 °C during heating. The abmpt change in the... 

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