Formation of a C15 Laves Phase with a Giant Unit Cell in Salt-Doped A/B/AB Ternary Polymer Blends

Gyroid Liquid Crystals as Quasi-Solid-State Electrolytes Toward Ultrastable Zinc Batteries

The potential for optimizing ion transport through triply periodic minimal surface (TPMS) structures renders promising electrochemical applications. In this study, as a proof-of-concept, we extend the inherent efficiency and mathematical beauty of TPMS structures to fabricate liquid-crystalline electrolytes with high ionic conductivity and superior structural stability for aqueous rechargeable zinc-ion batteries. The specific topological configuration of the liquid-crystalline electrolytes, featuring a Gyroid geometry, enables the formation of a continuous ion conduction pathway enriched with confined water. This, in turn, promotes the smooth transport of charge carriers and contributes to high ionic conductivity. Meanwhile, the quasi-solid hydrophobic phase assembled by hydrophobic alkyl chains exhibits notable rigidity and toughness, enabling uniform and compact dendrite-free Zn deposition. These merits synergistically enhance the overall performance of the corresponding full batteries. This work highlights the distinctive role of TPMS structures in developing high-performance, liquid-crystalline electrolytes, which can provide a viable route for the rational design of next-generation quasi-solid-state electrolytes.

Superlattice Engineering with Chemically Precise Molecular Building Blocks

Correlating nanoscale building blocks with mesoscale superlattices, mimicking metal alloys, a rational engineering strategy becomes critical to generate designed periodicity with emergent properties. For molecule-based superlattices, nevertheless, nonrigid molecular features and multistep self-assembly make the molecule-to-superlattice correlation less straightforward. In addition, single component systems possess intrinsically limited volume asymmetry of self-assembled spherical motifs (also known as "mesoatoms"), further hampering novel superlattices' emergence. In the current work, we demonstrate that properly designed molecular systems could generate a spectrum of unconventional superlattices. Four categories of giant molecules are presented. We systematically explore the lattice-forming principles in unary and binary systems, unveiling how molecular stoichiometry, topology, and size differences impact the mesoatoms and further toward their superlattices. The presence of novel superlattices helps to correlate with Frank-Kasper phases previously discovered in soft matter. We envision the present work offers new insights about how complex superlattices could be rationally fabricated by scalable-preparation and easy-to-process materials.

The C36 Laves phase in diblock polymer melts

The C14 and C15 Laves phases form as micelle packing structures in many types of soft matter, but the related C36 phase, which consists of alternating C14-type and C15-type layers, has not been observed in any such system. To understand this absence in the context of diblock polymers, we used self-consistent field theory to relate the morphology and energetics of C36 to other known mesophases. Two case studies were conducted: blends of AB diblock polymers with A homopolymers (where A forms the micelle core), in which C14 and C15 have stability windows, and neat AB diblock melts, in which Laves phases are metastable. Laves phases exhibit nearly identical micelle morphologies and nearly degenerate free energies, with the free energy of C36 being a near-perfect bisector of the C14 and C15 free energies in all cases, revealing an intrinsic symmetry in free energy that is attributed solely to the structural relationship between the phases in which the packing of C36 is intermediate between C14 and C15. Based on this connection between structure and free energy, C36 is thus not expected to form in flexible diblock polymers, since C14 and C15 can always form instead via facile mass transfer.

Enhancing ion transport in charged block copolymers by stabilizing low symmetry morphology: Electrostatic control of interfaces

Recently, the interest in charged polymers has been rapidly growing due to their uses in energy storage and transfer devices. Yet, polymer electrolyte-based devices are not on the immediate horizon because of the low ionic conductivity. In the present study, we developed a methodology to enhance the ionic conductivity of charged block copolymers comprising ionic liquids through the electrostatic control of the interfacial layers. Unprecedented reentrant phase transitions between lamellar and A15 structures were seen, which cannot be explained by well-established thermodynamic factors. X-ray scattering experiments and molecular dynamics simulations revealed the formation of fascinating, thin ionic shell layers composed of ionic complexes. The ionic liquid cations of these complexes predominantly presented near the micellar interfaces if they had strong binding affinity with the charged polymer chains. Therefore, the interfacial properties and concentration fluctuations of the A15 structures were crucially dependent on the type of tethered acid groups in the polymers. Overall, the stabilization energies of the A15 structures were greater when enriched, attractive electrostatic interactions were present at the micellar interfaces. Contrary to the conventional wisdom that block copolymer interfaces act as "dead zone" to significantly deteriorate ion transport, this study establishes a prospective avenue for advanced polymer electrolyte having tailor-made interfaces.

Crowding-Induced Unconventional Phase Behaviors in Dendritic Rodlike Molecules via Side-Chain Engineering

Dendritic molecules with a fanlike or conelike conformation are common molecular building blocks to construct supramolecular columnar or spherical phases. Although it is well-accepted that the preferred molecular conformation of dendritic molecules dictates their packing schemes, manipulation of this crucial parameter usually requires significant changes in molecular structures and tedious synthetic efforts. Herein, we report a simple yet highly efficient strategy to tune the molecular conformation of dendritic rodlike molecules by adjusting the length of alkyl side chains tethered to the rods. Strikingly, tiny chemical structure differences can largely change the "crowding" near the branching point to induce the "fanlike to conelike" conformational transitions and thus result in the formation of diverse supramolecular structures, including the columnar phase, double gyroid phase, and the unconventional Frank-Kasper σ and A15 phases. Our study provides a practical platform for further investigation of unconventional structure formation and phase transitions in soft matter.

Reevaluation of Poly(ethylene-alt-propylene)-block-Polydimethylsiloxane Phase Behavior Uncovers Topological Close-Packing and Epitaxial Quasicrystal Growth

Reanalysis of an asymmetric poly(ethylene-alt-propylene)-block-polydimethylsiloxane (PEP-PDMS) diblock copolymer first investigated in 1999 has revealed a rich phase behavior including a dodecagonal quasicrystal (DDQC), a Frank-Kasper σ phase, and a body-centered cubic (BCC) packing at high temperature adjacent to the disordered state. On subjecting the sample to large amplitude oscillatory shear well below the σ-BCC order-order transition temperature (T_OOT), small-angle X-ray scattering evidenced the emergence of a twinned BCC phase that, on heating, underwent a phase transition to an unusually anisotropic DDQC state. Surprisingly, we observe no evidence of this apparent epitaxy on heating or cooling through the equilibrium σ-BCC transition. We rationalize these results in terms of a shear-induced order-order transition and an apparent BCC-DDQC epitaxy favored by micelle translation-mediated ordering dynamics far below T_OOT.