Hydrodynamic and Molecular Study of Poly{4-[4-(hexyloxy)phenyl]ethynylphenyl methacrylate} in Dilute Solutions and Conformational Peculiarities of Brush-Like Macromolecules

• Published in: Macromolecular chemistry and physics 2012-05, Vol.213 (9), p.904-916
• Main Authors: Pavlov, Georges M., Breul, Alexander M., Hager, Martin D., Schubert, Ulrich S.
• Format: Article
• Language: English
• Subjects: analytical ultracentrifugation; brush-like macromolecules; chain conformational parameters; intrinsic viscosity; normalized scaling plots
• ISSN: 1022-1352; 1521-3935
• DOI: 10.1002/macp.201100653

Brush‐like poly{4‐[4‐(hexyloxy)phenyl]ethynylphenyl methacrylate}s are synthesized using RAFT polymerization, fractionated and studied by molecular hydrodynamic methods. The values of the velocity sedimentation coefficient, the frictional ratio, and the intrinsic viscosity are obtained in toluene. The conformational and structural parameters of the studied polymer chains are estimated by the use of theories that describe the hydrodynamic behavior of the wormlike cylinders without intra‐chain excluded volume effects and the hydrodynamic behavior of bending rods. The intrinsic viscosity data obtained for poly{4‐[4‐(hexyloxy)phenyl]ethynylphenyl methacrylate}s and for other brush‐like macromolecules are discussed in terms of a doubly‐normalized scaling plot. PHPhEPhM macromolecules are synthesized and peculiarities of their dilute‐solution properties are associated with their brush‐like structure. A measure of the “brush‐likeness” is the linear density of the chains. In a normalized plot of intrinsic viscosity vs. molar mass, the brush‐like macromolecules are discriminated in the appropriate region, which is characterized by high thickness of the molecules.