Highly Ordered Interconnected 1 nm Pores in Polymers Fabricated from Easily Accessible Gyroid Liquid Crystals

Polyhedral Polymeric Microparticles with Interwoven 1 nm Gyroid Pores for Precise Adsorption and Nanoconfined Degradation

Molecular-scale adsorption, catalysis, and separation demand nanoporous materials with high permeability, extensive surface areas, and pronounced nanoconfined effects. Fabricating polymeric particles with 3-D interwoven pores of ∼1 nm potentially addresses these needs. However, significant challenges remain in controlling their pore interconnectivity, uniformity, and achieving faceted particle shapes. Herein we present facile fabrication of polyhedral particles possessing interpenetrating 1 nm pores by suspension polymerization of double-gyroid (DG) liquid crystalline droplets. Mechanical stirring of the disordered phase at elevated temperatures, followed by undercooling, leads to the emulsification of DG droplets, as confirmed by synchrotron small-angle X-ray scattering (SAXS). UV-induced cross-linking of the DG droplets preserves the ordered network of 1 nm pores, as characterized by SAXS and microscopy. Intriguingly, due to the elasticity induced by the Ia3̅d periodicities, these particles adopt polyhedral shapes to avoid the elastic energy penalty associated with conventional sphericity. We demonstrate that these faceted particles, featuring 1 nm pores and efficient packing, enable rapid, size-exclusive adsorption and nanoconfined degradation of organic pollutants, driven by their 3-D permeability, high surface area, and enhanced nanoconfinement effects.

Double gyroid-structured electrolyte based on an azobenzene-containing monomer and its polymer

The self-assembled structure has a significant impact on the performance of ion conductors. We prepared a new type of electrolyte with self-assembled structures from an azobenzene-based liquid crystalline (LC) monomer and its corresponding polymer. By doping different amounts of monomers and lithium salt LiTFSI, the self-assembled nanostructure of the electrolyte was changed from lamellae to double gyroid. The ionic conductivity of the azobenzene-based electrolytes with the double gyroid structure was 1.64 × 10-4 S cm-1, higher than most PEO-based polymer electrolytes. The azobenzene-based system provides a new strategy to design solid electrolytes with self-assembled structures that may be potentially used in solid-state lithium-ion batteries.

Highly Ordered Gyroid Nanostructured Polymers: Facile Fabrication by Polymerizable Pluronic Surfactants

Highly ordered, network-nanostructured polymers offer compelling geometric features and application potential. However, their practical utilization is hampered by the restricted accessibility. Here, we address this challenge using commercial Pluronic surfactants with a straightforward modification of tethering polymerizable groups. By leveraging lyotropic self-assembly, we achieve facile production of double-gyroid mesophases, which are subsequently solidified via photoinduced cross-linking. The exceptionally ordered periodicities of Ia3d symmetry in the photocured polymers are unambiguously confirmed by synchrotron small-angle X-ray scattering (SAXS), which can capture single-crystal-like diffraction patterns. Electron density maps reconstructed from SAXS data complemented by transmission electron microscopy analysis further elucidate the real-space gyroid assemblies. Intriguingly, by tuning the cross-linking through thiol-acrylate chemistry, the mechanical properties of the polymer are modulated without compromising the integrity of Ia3d assemblies. The 3-D percolating gyroid nanochannels demonstrate an ionic conductivity that surpasses that of disordered structures, offering promising prospects for scalable fabrication.

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.

Boosting Phosphoric Acid Retention in Polymer Electrolyte Membranes by Zwitterions: Insights from DFT Calculations and MD Simulations

Effective retention of phosphoric acid (PA) is crucial for the efficient operation of fuel cells based on PA-doped polymeric membranes, which is highly challenging due to the moisture-induced loss of PA. Therefore, a comprehensive understanding of the interplay among PA, functional groups, and water is essential for designing membrane materials. Using density functional theory (DFT) calculations and molecular dynamics (MD) simulations, we unveil the remarkable capability of zwitterions to effectively sequester PA, thereby unlocking the potential for fuel cell optimization. Our DFT calculations show that zwitterions, termed "charged proton-accepting bases", exhibit stronger interactions with PA compared to the traditional neutral proton-accepting bases. Furthermore, the presence of water amplifies such a discrepancy, with the zwitterion-PA interactions playing a dominant role in the zwitterion-PA-water cluster due to the strongest affinity of zwitterions to PA. Conversely, the ability of neutral bases to retain PA is significantly attenuated by moisture as the interactions between water and PA surpass those between neutral bases and PA. The strong zwitterion-PA associations arise primarily from the formation of multiple hydrogen bonds. Furthermore, MD simulations reveal the uniform distribution of zwitterions in aqueous environments and their pronounced affinities for both PA and water. In contrast, neutral bases tend to aggregate, interacting limitedly with PA. These findings underscore the effectiveness of zwitterions in boosting PA retention in fuel cells.

Stimuli-responsive viscosity modifiers

Stimuli responsive viscosity modifiers entail an important class of materials which allow for smart material formation utilizing various stimuli for switching such as pH, temperature, light and salinity. They have seen applications in the biomedical space including tissue engineering and drug delivery, wherein stimuli responsive hydrogels and polymeric vessels have been extensively applied. Applications have also been seen in other domains like the energy sector and automobile industry, in technologies such as enhanced oil recovery. The chemistry and microstructural arrangements of the aqueous morphologies of dissolved materials are usually sensitive to the aforementioned stimuli which subsequently results in rheological sensitivity as well. Herein, we overview different structures capable of viscosity modification as well as go over the rheological theory associated with classical systems studied in literature. A detailed analysis allows us to explore correlations between commonly discussed models such as molecular packing parameter, tube reptation and stress relaxation with structural and rheological changes. We then present five primary mechanisms corresponding to stimuli responsive viscosity modification: (i) packing parameter modification via functional group conditioning and (ii) via dynamic bond formation, (iii) mesh formation by interlinking of network nodes, (iv) viscosity modification by chain conformation changes and (v) viscosity modification by particle jamming. We also overview several recent examples from literature that employ the concepts discussed to create novel classes of intriguing stimuli responsive structures and their corresponding rheological properties. Furthermore, we also explore systems that are responsive to multiple stimuli which can provide enhanced functionality and versatility by providing multi-level and precise actuation. Such systems have been used for programmed site-specific drug delivery.

Stabilizing Differential Interfacial Curvatures by Mismatched Molecular Geometries: Toward Polymers with Percolating 1 nm Channels of Gyroid Minimal Surfaces

Soft materials with self-assembled networks possess saddle-shaped interfaces with distributed negative Gaussian curvatures. The ability to stabilize such a geometry is critically important for various applications but can be challenging due to the possibly "deficient" packing of the building blocks. This nontrivial challenge has been manifested, for example, by the limited availability of cross-linkable bicontinuous cubic (Q) liquid crystals (LCs), which can be utilized to fabricate compelling polymers with networked nanochannels uniformly sized at ∼1 nm. Here, we devise a facile approach to stabilizing cross-linkable Q mesophases by leveraging the synergistic self-assembly from pairs of scalably synthesized polymerizable amphiphiles. Hybridization of the molecular geometries by mixing significantly increases the propensity of the local deviations in the interfacial curvature specifically required for Q assemblies. "Normal" (type 1) double gyroid LCs possessing 1 nm ionic channels conforming to minimal surfaces can be formulated by simultaneous hydration of the amphiphile mixtures, as opposed to the formation of hexagonal or lamellar mesophases exhibited by the single-amphiphile systems, respectively. Fixation of the bicontinuous network in polymers via radical polymerization has been efficaciously facilitated by the presence of the bifunctional polymerizable groups in one of the employed amphiphiles. High-fidelity lock-in of the ordered continuous 1 nm channels has been unambiguously confirmed by the observation of single-crystal-like diffraction patterns from synchrotron small-angle X-ray scattering and large-area periodicities by transmission electron microscopy. The produced polymeric materials exhibit the required mechanical integrity as well as chemical robustness in a variety of organic solvents that benefit their practical applications for selective transport of ions and molecules.

Stable cross-linked lyotropic gyroid mesophases from single-head/single-tail cross-linkable monomers

A single-head/single-tail surfactant with a polymerizable group at each end is presented as a new simplified motif for intrinsically cross-linkable, gyroid-phase lyotropic mesogens. The resulting nanoporous polymer networks exhibit excellent structural stability in various solvents and are capable of molecular size discrimination.