The precise molecular engineering of amphiphilic diblock copolymers as thermoresponsive polymer ionic liquids (PILs) couples polyisobutylene (PIB) and poly(2ethyl-2-oxazoline) (PEtOx) blocks via an imidazolium cation. It enables thermal switching of micellar self-assembly and yields nanostructured hydrogels. Just one ionic liquid (IL)type imidazolium cation is readily incorporated into the backbone of the PIB−IL−PEtOx block copolymers by terminating the cationic 2-ethyl-2-oxazoline (EtOx) ringopening polymerization by alkylation of an imidazoleterminated PIB. The PEtOx block length varies as a function of the PIB-imidazole/EtOx molar ratio and governs solubility, hydrophilic/hydrophobic balance, and nanophase separation. In spite of the presence of highly hydrophobic PIB segments, PIB−IL−PEtOx are rendered water soluble with increasing PEtOx block length and form spherical and elongated micelles as well as hydrogels exhibiting wormlike nanostructures. Furthermore, the lower critical solution temperature of PEtOx segments is the key to thermoresponsive behavior of both water-soluble copolymers and copolymer hydrogels. Owing to low glass temperature and high stability of PIB, these PIB−PILs represent attractive macromolecular nanosystems enabling thermal switching of solubilization, dispersion, transport, and shuttling of molecules and nanoparticles.

Despite the great interest in nanoconfined materials nowadays, nanocompartmentalized poly(ionic liquid)s (PILs) have been rarely investigated so far. Herein, we report on the successful alkylation of poly(1-vinylimidazole) with methyl iodide in bicontinuous nanophasic poly(1-vinylimidazole)-l-poly(tetrahydrofuran) (PVIm-l-PTHF) amphiphilic conetworks (APCNs) to obtain nanoconfined methylated PVImMe-l-PTHF poly(ionic liquid) conetworks (PIL-CNs). A high extent of alkylation (~95%) was achieved via a simple alkylation process with MeI at room temperature. This does not destroy the bicontinuous nanophasic morphology as proved by SAXS and AFM, and PIL-CNs with 15–20 nm d-spacing and poly(3-methyl-1-vinylimidazolium iodide) PIL nanophases with average domain sizes of 8.2–8.4 nm are formed. Unexpectedly, while the swelling capacity of the PIL-CN dramatically increases in aprotic polar solvents, such as DMF, NMP, and DMSO, reaching higher than 1000% superabsorbent swelling degrees, the equilibrium swelling degrees decrease in even highly polar protic (hydrophilic) solvents, like water and methanol. An unprecedented Gaussian-type relationship was found between the ratios of the swelling degrees versus the polarity index, indicating increased swelling for the nanoconfined PVImMe-l-PTHF PIL-CNs in solvents with a polarity index between ~6 and 9.5. In addition to the nanoconfined structural features, the unique selective superabsorbent swelling behavior of the PIL-CNs can also be utilized in various application fields.