Polymerization-induced phase separation (PIPS) is the occurrence of

phase separation Phase separation is the creation of two distinct phases from a single homogeneous mixture. The most common type of phase separation is between two immiscible liquids, such as oil and water. Colloids are formed by phase separation, though n ...

in a multicomponent mixture induced by the

polymerization In polymer chemistry, polymerization (American English), or polymerisation (British English), is a process of reacting monomer, monomer molecules together in a chemical reaction to form polymer chains or three-dimensional networks. There are ...

of one or more components. The increase in molecular weight of the reactive component renders one or more components to be mutually

immiscible Miscibility () is the property of two chemical substance, substances to mix in all mixing ratio, proportions (that is, to fully dissolution (chemistry), dissolve in each other at any concentration), forming a homogeneity and heterogeneity, homoge ...

in one another, resulting in spontaneous phase segregation.

Types

Polymerization-induced phase separation can be initiated either through thermally induced polymerization or photopolymerization. The process general occurs through

spinodal decomposition Spinodal decomposition is a mechanism by which a single thermodynamic phase spontaneously separates into two phases (without nucleation). Decomposition occurs when there is no thermodynamic barrier to phase separation. As a result, phase separatio ...

, commonly resulting in the formation of co-continuous phases.

Control over morphology

The morphology of the final phase separated structures are generally random owing to the stochastic nature of the onset and process of phase separation. Several approaches have been investigated to control morphology. Tran-Cong-Miyata and co-workers using periodic irradiation in photoreactive polymer blends to control morphology, specifically width of the resultant spinodal modes in the phase separated morphology. Li and co-workers employed holography, a process of holographic polymerization, in to order to direct the phase separated structure to have the same patterns as the holographic field. Recently, Hosein and co-workers demonstrated that nonlinear optical pattern formations that occur in photopolymer systems may be used to direct the organization of blends to have the same morphology as the light pattern.

Applications

The process is commonly used in control of the morphology of polymer blends, for applications in thermoelectrics, solid-state lighting, polymer electrolytes, composites, membrane formation, and surface pattern formations.

References

{{reflist __notoc__ Polymer chemistry