Figure-Eight-Shaped and Cage-Shaped Cyclic Polystyrenes

Nonlinear polystyrenes (PS) with similar molecular weights but with different molecular structures having star-, figure-8-, and cage-shaped architectures were synthesized by combining atom transfer radical polymerization (ATRP) and click chemistry. Figure-8- and cage-shaped PS were fractionated by using a gradient normal phase liquid chromatography as confirmed by SEC-LS, MALDI-TOF MS, ¹H NMR, and FT-IR spectrometry. Their purities were estimated by using a two-dimensional liquid chromatography (2D-LC). The glass transition temperatures of these topologically different polymers were in the order of cage-, figure-8-, and star-shaped polymers possibly due to the multiple links that constrain the overall molecular diffusivity in the case of multicyclic polymers (figure-8, and cage). Monte Carlo simulation on the glass transition behavior of model system also agreed well with the experimental results.