Synthesis, dilute solution properties, and chain flexibility of poly(difluorobenzyl methacrylates)

The synthesis and dilute solution behavior of poly(2,5-difluorobenzyl metha crylate) (P2,5-DFBM) and poly(2,6-difluorobenzyl methacrylate) (P2,6-DFBM) are described. The polymers were characterized by viscosity and classical l ightscattering and size exclusion chromatography (SEC) measurements. The Ku hn-Mark-Houwink-Sakurada (KMHS) relationships were established. Unperturbed dimensions <r(0)(2)>(1/2), the rigidity factor sigma, the characteristic r atio C-infinity and the thermodynamic parameters were determined using the Stockmayer-Fixman treatment. The double substitution in the 2,5 and 2,6 pos itions by fluorine atoms increases the conformational parameters. The prese nce of substituents such as -CH3 or fluorine atoms close to the main chain (2,6 position) affects the internal rotation potential in the same way.