Poly(N-vinylimidazole)-/-Poly(tetrahydrofuran) Amphiphilic Copetworks and Gels: Synthesis, Characterization, Thermal and Swelling Behavior

A novel class of amphiphilic conetworks (APCNs), poly(N-vinylimidazole)-l-poly(tetrahydrofuran) (PVIm-l-PTHF) (l stands for linked by), was prepared by free radical copolymerization of telechelic PTHF dimethacrylate macromonomer and N-vinylimidazole in ethanol as a suitable cosolvent for all the components. Low amounts of extractables were obtained indicating successful conetwork formation. A series of transparent, macroscopically homogeneous PVIm-l-PTHF conetworks with a wide composition range of 25-89 wt % PTHF were prepared. Investigations by DSC revealed the existence of two distinct glass transition temperatures (T-g) in the vicinity of the T-g, of homopolymers proving microphase separation of PVIm and PTHF in these conetworks. Surprisingly, the crystallization of PTHF is strongly suppressed and prevented at lower than 38 wt % PTHF in the presence of the glassy, amorphous PVIm in these APCNs. The amphiphilic nature of the PVIm-l-PTHF conetworks was proved by their uniform swelling in both nonpolar (tetrahydrofuran, carbon tetrachloride) and polar solvents (water, methanol) in a broad composition range, indicating bicontinuous (cocontinuous) phase separation in these novel, unique bicomponent polymeric materials.