There is a strong interest in use of `smart polymers' in separation systems. These are polymers which can react on external influence, such as temperature or pH change. With such polymers it is possible from the outside to affect the properties of a separation system. Amphiphilic copolymers show drastic changes in solubility properties, such as self-association and phase separation, at e.g. temperature increase. The random copolymers of ethylene oxide and propylene oxide units (EOPO-polymers) can form aqueous two-phase systems above the copolymer cloud point temperature. Two phases are formed, one consisting of 40-60% polymer in water and the other of almost 100% water. Amino acids and peptides can be partitioned in the thermoseparating systems. The partitioning strongly depends on the solute hydrophobicity, where aromatic amino acids and peptides are partitioned to the polymer phase and hydrophilic to the water phase. Salt effects can be used to enhance the partitioning of charged molecules. The thermodynamic driving forces which govern the partitioning of molecules in a thermoseparated aqueous phase system is described with use of the Flory-Huggins theory for polymer solutions. Expressions are derived which show the entropic and enthalpic effects on solute partitioning.
Bibliographical noteThe information about affiliations in this record was updated in December 2015.
The record was previously connected to the following departments: Theoretical Chemistry (S) (011001039), Biochemistry and Structural Biology (S) (000006142)
Subject classification (UKÄ)
- Theoretical Chemistry
- Biological Sciences
- aqueous two-phase system
- Flory-Huggins theory
- phase separation
- temperature-induced phase separation
- thermoseparating polymer