Polymer–polymer interaction

Aqueous two-phase system is widely used in the purification, recovery, and separation of biomolecules. When compared to the conventional method of purification, aqueous two-phase system reduces overall cost and omits the use of multistep procedures. The polymer–polymer aqueous two-phase system is made up of two water-soluble polymers above a critical concentration, in which polyethylene glycol and dextran are the most commonly used components. To address the drawback of high polymer cost, cheaper alternatives such as tree gum, xanthan, and starch derivatives were proposed. The book chapter discusses the principles of polymer–polymer aqueous two-phase system and the partitioning behavior of biomolecules by using a phase diagram. Moreover, the parameters that influence phase formation were evaluated. The chapter also reviewed the application of the polymer–polymer aqueous two-phase system in the pharmaceutical and biotechnological industries. Future prospects and research gaps were also addressed for future development of the polymer–polymer aqueous two-phase system.