Block Copolymers

INQUIRY

A copolymer is a polymer created by polymerizing two or more monomers, as opposed to a homopolymer, which is created by polymerizing only one monomer. Unlike a mixture of two polymers created by mechanical or physical mixing, a copolymer has at least two structural units in its structure that are chemically connected to each other. Block copolymers (BCPs) undergo microphase separation and form ordered forms at equilibrium. Micelles, spheres, cylinders, sheets, and surface patterns are examples of morphologies.

Fig 1. Representative architectures of linear block terpolymers, 'comb' graft polymers, miktoarm star terpolymers, and cyclic block terpolymers.

Applications:

As a thermoplastic elastomer

One of the most important technical applications of BCP is as a thermoplastic elastomer (TPE). This type of BCP typically contains physically cross-linked rigid glass-like areas and continuous soft rubber-like areas. It has the elasticity of conventional rubber and, because it is not chemically cross-linked, is suitable for typical plastics processes such as injection molding and melt extrusion.

In drug delivery and release

Over the past decade, advanced nanoscale systems created through BCP self-assembly have made great strides in drug delivery applications.Advances in BCP self-assembly provide effective control over morphology, surface chemistry, and environmental responsiveness. Among these nanostructures, micelles and vesicles are the most studied morphologies. Block copolymer micelles are of interest in drug delivery applications for several reasons.

In soft lithography

Directed self-assembly (DSA) of BCPs is one of the prominent candidates for soft lithography because they can form ordered features on length scales down to a few nanometers, which is necessary for many of the most demanding next-generation patterning applications.

In mesoporous materials

Self-assembly of BCPs may result in a range of interesting 2D or 3D morphologies, making them useful as structure-directed "templates" for the fabrication of porous materials.