Shape-persistent, conductive ionogels where both mechanical strength and ionic conductivity are enhanced are developed using multiphase materials composed of cellulose nanocrystals and hyperbranched polymeric ionic liquids (PILs) as a mechanically strong supporting network matrix for ionic liquids with an interrupted ion-conducting pathway. The integration of needlelike nanocrystals and PIL promotes the formation of multiple hydrogen bonding and electrostatic ionic interaction capacitance, resulting in the formation of interconnected networks capable of confining a high amount of ionic liquid (≈95 wt%) without losing its self-sustained shape. The resulting nanoporous and robust ionogels possess outstanding mechanical strength with a high compressive elastic modulus (≈5.6 MPa), comparable to that of tough, rubbery materials. Surprisingly, these rigid materials preserve the high ionic conductivity of original ionic liquids (≈7.8 mS cm −1 ), which are distributed within and supported by the nanocrystal network-like rigid frame. On the one hand, such stable materials possess superior ionic conductivities in comparison to traditional solid electrolytes; on the other hand, the high compression resistance and shapepersistence allow for easy handling in comparison to traditional fluidic electrolytes. The synergistic enhancement in ion transport and solid-like mechanical properties afforded by these ionogel materials make them intriguing candidates for sustainable electrodeless energy storage and harvesting matrices.

We synthesized amphiphilic hyperbranched poly(ionic liquid)s (HBPILs) with asymmetrical peripheral composition consisting of hydrophobic n-octadecylurethane arms and hydrophilic, ionically linked poly(N-isopropylacrylamide) (PNIPAM) macrocations and studied low critical solution temperature (LCST)-induced reorganizations at the air−water interface. We observed that the morphology of HBPIL Langmuir monolayers is controlled by the surface pressure with uniform well-defined disk-like domains formed in a liquid phase. These domains are merged and transformed to uniform monolayers with elevated ridge-like network structures representing coalesced interdomain boundaries in a solid phase because the branched architecture and asymmetrical chemical composition stabilize the disk-like morphology under high compression. Above LCST, elevated individual islands are formed because of the aggregation of the collapsed hydrophobized PNIPAM terminal macrocations in a solid phase. The presence of thermoresponsive PNIPAM macrocations initiates monolayer reorganization at LCST with transformation of surface mechanical contrast distribution. The heterogeneity of elastic response and adhesion distributions for HBPIL monolayers in the wet state changed from highly contrasted two-phase distribution below LCST to near-uniform mechanical response above LCST because of the hydrophilic to hydrophobic transformation of the PNIPAM phase.

We synthesized novel amphiphilic hyperbranched polymers (HBPs) with variable contents of weakly ionically tethered thermoresponsive poly­(N-isopropylacrylamide) (PNIPAM) macrocations in contrast to traditional covalent linking. Their assembling behavior was studied below and above the lower critical solution temperature (LCST). The HBPs underwent a morphological transition under changing temperature and ionic strength due to the LCST transition of PNIPAM and the reduction in the ionization degree of terminal ionic groups, respectively. We suggest that, in contrast to traditional branched polymers, ionically linked PNIPAM macrocations can reversibly disassociate from the sulfonate groups and form mobile coronas, endowing the dynamic micellar morphologies. In addition, assembly at the air–water interface confined PNIPAM macrocations and resulted in the formation of heterogeneous Langmuir–Blodgett (LB) monolayers with diverse surface morphologies for different peripheral compositions with circular domains formed in the condensed state. The HBPs with 25% PNIPAM showed larger and more stable circular domains that were partially preserved at high compression than those of HBPs with 50% PNIPAM. Moreover, the LB monolayers showed variable surface mechanical and surface charge distribution, which can be attributed to net dipole redistribution caused by the behavior of mobile PNIPAM macrocations and core sulfonate groups.