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

The synthesis and dilute solution behavior of poly(2,5-difluorobenzyl methacrylate) (P2,5-DFBM) and poly(2,6-difluorobenzyl methacrylate) (P2,6-DFBM) are described. The polymers were characterized by viscosity and classical light-scattering and size exclusion chromatography (SEC) measurements. The Kuhn-Mark-Houwink-Sakurada (KMHS) relationships were established. Unperturbed dimensions 〈r₀²〉 ^1/2 , the rigidity factor σ, the characteristic ratio C_∞, and the thermodynamic parameters were determined using the Stockmayer-Fixman treatment. The double substitution in the 2,5 and 2,6 positions by fluorine atoms increases the conformational parameters. The presence 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.