Dimensional characterizations from rod stars to brushes (PSt-g-HIC-32) with a relatively low degree of polymerization of the main chain have been studied in tetrahydrofuran (THF) at 25 °C by employing synchrotron radiation small-angle X-ray scattering, static and dynamic light scatterings, and viscosity measurements. The rod stars and brushes consist of a flexible linear polystyrene (PSt) main chain and 32 n-hexyl isocyanate (HIC) units in each side chain. Eight PSt-g-HIC-32 samples with a weightaverage degree of polymerization (NM) of 11-495 of the main chain and a narrow molecular weight distribution (Mw/Mn) of 1.08-1.17 were prepared using a recycling preparative size-exclusion chromatography (SEC) system. The mean-square radius of gyration (〈S2〉), hydrodynamic radius (RH), and intrinsic viscosity ([η]) of the stars and brushes were tabulated. The absolute calibration curve obtained in SEC analysis, scattering form factor, and ρ (==〈S2〉1/2/RH) parameter indicated a continuous change in the shape from the rod star to rod brush on increasing the aspect ratio of the main chain to the side chain. The NM dependences of 〈S2〉, RH, and [η] were consistently and quantitatively described using the current theories based on a wormlike (sphero-) cylinder model by taking into account the effective protruding effects of the side chains near the ends of the main chain.
All Science Journal Classification (ASJC) codes
- Organic Chemistry
- Polymers and Plastics
- Inorganic Chemistry
- Materials Chemistry