Self-assembly of rod–coil block copolymers

• Published in: Materials science & engineering. R, Reports : a review journal Vol. 62; no. 2; pp. 37 - 66
• Main Authors: Olsen, Bradley D., Segalman, Rachel A.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 30.07.2008; Elsevier Science
• Subjects: Applied sciences; Block copolymers; Exact sciences and technology; Helix; Natural polymers; Organic electronics; Organic polymers; Phase behavior; Physicochemistry of polymers; Properties and characterization; Proteins; Rod-coil; Self-assembly; Semiflexible; Solution and gel properties; Structure, morphology and analysis; Thin film; Semiflexible; Self-assembly; Rod-coil; Helix; Phase behavior; Block copolymers; Thin film; Organic electronics; Self assembly; Chemical solution; Patterning; Molten state; Gelation; Aromatic polymer; Review; Isocyanate polymer; Protein; Conducting polymers; Triblock copolymer; Liquid crystal polymers; Block copolymers,Rod-coil,Semiflexible,Self-assembly,Thin film,Helix,Organic electronics,Phase behavior; Diblock copolymer; Micellar solution; Block copolymer; Conformation
• ISSN: 0927-796X; 1879-212X
• DOI: 10.1016/j.mser.2008.04.001

Rod–coil block copolymers are an increasingly important class of molecules for the self-assembly of functional polymer systems, many of which have rodlike chain conformations due to rigid secondary structures, extended π-conjugation, or aromatic groups along the polymer backbone. Examples of these polymers are helical proteins, polyisocyanates, main-chain semiconducting polymers, and aromatic polyesters, polyamides, or polyimines. Many hindered or liquid crystalline systems self-assembled from block copolymers, including dendronized polymers and mesogen-jacketed liquid crystalline polymers, also form rod–coil block copolymers. In these cases, steric crowding of the bulky or mesogenic side chains causes the polymer backbone to become quasi-linear. The incorporation of rigid rod polymers into the block copolymers results in extremely rich self-assembly behavior that differs markedly from that of traditional block copolymers due to the interplay between microphase separation of the rod and coil components and liquid crystalline alignment. The combination of these effects results in novel structures both in solution and melts. This review discusses in detail the self-assembly and thermodynamics of rod–coil diblock and triblock copolymers. After summarizing the applications of these materials, their aggregation and gelation in solution is discussed. Our knowledge of their bulk phase behavior is thoroughly reviewed both from the experimental and theoretical perspectives, and the self-assembly of these materials in thin film geometries that are critical to many applications in organic electronics and functional surface patterning is treated. Finally, the outlook for the future of these systems is summarized along with current knowledge gaps and exciting areas for the advancement of the field.