Poly(<i>N</i>-vinylimidazole)-<i>l</i>-Poly(tetrahydrofuran) Amphiphilic Conetworks and Gels: Synthesis, Characterization, Thermal and Swelling Behavior

Abstract

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 (Tg) in the vicinity of the Tg 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.