blockkopolymere

Blockkopolymere, or block copolymers, are macromolecules composed of two or more chemically distinct polymer blocks linked covalently in a single chain. The blocks are typically of different polarity or thermal properties, which promotes phase separation on the nanoscale rather than macroscopic mixing.

In linear forms the simplest are diblock (A-B) and triblock (A-B-A or B-A-B); more complex multiblock, branched, star, and graft architectures also exist. Due to incompatibility between blocks, blockkopolymere form microphase-separated domains with characteristic spacings of a few to several tens of nanometers, yielding ordered morphologies such as lamellae, cylinders, gyroids, or spheres depending on block volume fractions and the interaction parameter between blocks (chi).

Blockkopolymere are synthesized by sequential living polymerization or coupling techniques. Methods include living anionic polymerization, atom transfer radical polymerization (ATRP), and reversible addition-fragmentation chain transfer (RAFT) polymerization, enabling precise control of block lengths and narrow dispersities. Architectures can be built by successive monomer additions or by linking preformed macroinitiators.

Applications exploit nanoscale phase separation to tailor properties. They serve as thermoplastic elastomers, nanostructured membranes, templates for lithography, and drug-delivery carriers where micelles encapsulate hydrophobic drugs or enable controlled release.

Characterization relies on transmission or scanning electron microscopy, small-angle X-ray or neutron scattering, and differential scanning calorimetry to assess morphology, domain spacing, and thermal transitions. Considerations include synthesis cost, scalability, and recyclability challenges.