GIANT最新文献

Liquid crystal elastomers (LCEs) are a kind of soft actuating materials with large reversible deformation ability, which can work as the “motor” to exhibit complex deformations and drive the locomotion of soft robots. The deformation of LCEs depends on the three-dimensional (3D) shape of whole structure and alignment patterns of mesogens. Various methods have been employed to fabricate the LCE structure with desired shapes and mesogen alignments. However, conventional 3D printed LCEs require continuous thermal energy input to maintain their actuated shapes. The LCEs cannot be reprocessed and reprogrammed once cured. Herein, we introduce dynamic boronic ester bonds into the ink, with which the printed LCE structures are capable of being reprogrammed from polydomain into monodomain state and vice versa. We further explore the effects of printing parameters and content of dynamic covalent bonds on the actuation performance and reprogramming ability. The actuated shape could be well predicted with finite element method. The dynamic printable LCEs developed here offer new strategy and large design space for LCE structures.

Single crystal growth and characterization of the lithium bis(trifluoromethyl sulfonyl)imide (LiTFSI), the most common electrolyte salt for lithium-ion batteries, have been performed and succeeded in unraveling the atomic structures of its different crystalline phases. The structures of two crystalline phases (phase I: orthorhombic, Pccn; phase II: monoclinic, P2₁/c) have been determined through temperature-dependent X-ray crystallography of the LiTFSI single crystal on heating, and the solid-solid phase transformation between phase I and phase II has been dictated. Interestingly, a conformational change of TFSI⁻ from transoid to cisoid has been discovered during the transition from phase I to phase II, which has been further confirmed by the temperature-dependent Raman spectroscopy. The coordination of Li⁺ with the TFSI⁻ ions of different conformations has been also elucidated in the polymorphic crystalline structures. The solid-solid phase transformation of the first-order leads to the cracking of the LiTFSI crystal, probably along the lithium-ion or the fluorine-rich layer in phase II. In the molten state, the coexistence of the transoid conformation and the cisoid conformation is found in the TFSI⁻ ions, affirming the recent observation in the concentrated non-crystalline state. This work is anticipated to shed light on the (de)solvation and the transport of lithium ions in complex fluids encompassing LiTFSI electrolyte solutions from the structural aspects.

The structure of mRNA lipid nanoparticles (LNPs) is still under debate, with different studies presenting varying morphological characteristics, significantly hindering their biomedical potential. A typical formulation process of mRNA LNPs involves three steps: initial rapid mixing of lipids in an ethanol phase and mRNA in an acidic aqueous phase, followed by the swift removal of ethanol, and finally adjusting the solution to a neutral environment. In this study, we utilize Small Angle Neutron Scattering (SANS) with contrast matching to reveal the kinetic pathway-dependent of mRNA LNPs morphology. We find that the formulation process of the Moderna COVID-19 vaccine is controlled by a competition between aggregation and microphase separation, dictating the diverse morphologies observed in mRNA LNPs. The first step leads to the formation of polydisperse spherical droplets with an average diameter of 42±6.0 nm in an acidic ethanol aqueous solution. Ethanol removal initiates both aggregation and internal microphase separation, resulting in a polydisperse core-shell structure with an average diameter of 48±3.7 nm. Heptadecan-9-yl 8-((2-hydroxyethyl) (6-oxo-6-(undecyloxy) hexyl) amino) octanoate (SM-102) binds to mRNA via electrostatic interaction to form a reverse-wormlike micelle structure inside. The 1,2-Distearoyl-sn‑glycero-3-phosphocholine (DSPC) and PEG-lipid are just in the shell and cholesterol acting as a filler throughout the core-shell structure. Upon transitioning to a neutral environment, SM-102 loses its charge and neither the periphery nor the reverse-wormlike micelle can maintain their stabilities, leading to further aggregation and microphase separation. The average diameter of core-shell structure turns to be 66±5.2 nm. In the actual formulation process of the Moderna COVID-19 vaccine, steps 2 and 3 occur simultaneously, and the competition between aggregation and microphase separation determines the final morphology. These findings offer crucial insights into optimizing the morphology of mRNA LNPs, thereby facilitating advancements in vaccine development and mRNA vaccine delivery technologies.

This work reports the effect of 1–5 wt% epoxidized soybean oil (ESO) addition on the thermal, mechanical, and morphological properties of polybutylene succinate (PBS). ESO acts as a chain extender as well as a mild plasticizer of PBS. N-methylimidazole (NMI) is used as a catalyst to promote the reaction between PBS and ESO, and thermal, rheological, and spectroscopic analyses demonstrate increased viscoelastic properties, compatibility, crystallinity and thermal stability of the melt reacted formulations. In the presence of NMI, storage modulus (G’) values two orders of magnitude higher than that of pure PBS are achieved, confirming the completion of the chain extension reaction. A drastic refinement of the biphasic structure of the blend is observed, with the formation of a homogenous structure where ESO is well incorporated into the matrix. Finally, tensile tests reveal enhanced mechanical performance in the blends reacted in the presence of NMI. These findings pave the way for the development of a versatile family of materials which could find potential application in sustainable biodegradable packaging.

Liquid crystals, as typical anisotropic building blocks, tend to self-assemble into various ordered architectures during distinct thermodynamic processes. Research on the underlying mechanisms and rules may drastically promote our understanding of complicated structures. Here, zigzag focal conic domains (ZFCDs) are generated in rapid cooling process under an antagonistic boundary condition. After several thermal cycles beneath the nematic-smectic (N-S) phase transition point, the ZFCDs are well regularized. We found that the dislocations associated with the rapid cooling play vital roles in the formation of ZFCDs. A strong interphase correlation between the zigzag ± 1/2 disclination pairs and ZFCDs is observed above the N-S phase transition point. The orientational order inheritance and topological invariance across the phase transition indicate that similar disclination pairs exist in ZFCDs. These disclination pairs facilitate the opposite tilt direction and a half-pitch lateral shift between neighboring focal conic domains (FCDs), thus forming ZFCDs. During thermal cycles, the thermal motion of molecules induces the regularization and elimination of defect cores, further resulting in the ordered ZFCDs. Via properly controlling the cooling rate, large-area ordered ZFCDs are achieved in a wide film thickness range after thermal cycles. This study enriches the knowledge on the topological defect guided architecture of liquid crystals and may pave the way for the generation and regularization of ordered self-assembled systems.

Ternary organic solar cells (OSCs) are the feasible and efficient strategy to achieve the high-performance OSCs. It is of great significance to develop a superior third component candidate for constructing efficient ternary OSCs. In this work, we intelligently designed and synthesized a dimerized small molecule donor by connecting two asymmetric small molecule donors with the vinyl group, which is named DSMD-βV. This innovative oligomeric molecule DSMD-βV not only exhibits the complementary absorption and the cascade energy level arrangement with PM6 and BTP-eC9, but also regulates the phase separation micromorphology based on PM6:BTP-eC9. Consequently, PM6:DSMD-βV:BTP-eC9 based ternary device exhibits the improved exciton dissociation, charge transport and decreased recombination, thus achieving a superior power conversion efficiency (PCE) of 18.26 %, surpassing PM6:BTP-eC9 based binary (17.63 %). This work indicates that the dimerized small molecule donor is able to become a promising third component candidate, which also opens up a unique idea for the construction of efficient ternary organic solar cells.

Biomimetic damping materials have emerged as promising candidates for various applications due to their ability to mimic the exceptional damping properties observed in biological systems. This review provides a comprehensive overview of recent advances in the field of biomimetic damping gel materials. The conceptual framework of biomimetic damping materials is discussed, the synthesis methods inspired by biological principles are elucidated, and key considerations in material selection are highlighted. The latest research findings on the mechanical properties, biocompatibility and practical applications of these materials are synthesized and insights into the future directions of biomimetic damping gel materials are offered.

Inspired by the extracellular matrix (ECM), biomaterials have emerged as promising strategies in the biomedical research and engineering domain, offering unique characteristics for tissue regeneration, drug delivery, therapeutic interventions, and cellular investigations. The ECM, a dynamic network structure secreted by various cells, primarily comprises diverse proteins capable of facilitating tissue-ECM signaling and regulatory functions through its rich array of bioactive substances and multi-level structural properties. Drawing inspiration from the intricate structure and biochemical composition of natural ECM, researchers have developed various biomaterials to encapsulate these features and create biomimetic microenvironments, such as electrospinning, hydrogels/hydrogel microspheres, decellularized ECM(dECM), and ECM-mimicking peptides. Furthermore, by mimicking the structural composition of ECM components, ECM-inspired biomaterials exhibit varying degrees of ECM functionalization, including providing structural support, cell adhesion, signal transduction, mitigating immune responses, and tissue remodeling. In summary, the advancements in ECM-inspired biomaterials offer significant promise in addressing key challenges in the fields of tissue engineering, regenerative medicine, and drug delivery.

The thin film morphology of double-cable conjugated polymers is critical to the performance of single-component organic solar cells (SCOSCs). Here, we explore the effect of thin film crystallinity on device performance by varying the thermal annealing temperature used during device fabrication. Our investigations reveal that a moderate annealing temperature of 150 °C optimizes the power conversion efficiency in SCOSCs. Although higher annealing temperatures leads to increased crystalline order, a decrease in device performance is observed, attributed to imbalanced carrier transport and increased charge recombination. Additionally, the progressive decrease in the open-circuit voltage of these cells with increasing annealing temperature is linked to augmented non-radiative voltage losses, stemming from the increase in film crystallinity. This study underscores the critical necessity of achieving a delicate optimization of film microstructure in order to maximize the efficiency of SCOSCs, while also delineating prospective avenues for refining the molecular design and processing of double-cable polymers to bolster solar cell performance.

Traditional impact-resistance materials relying on the combination of supporting materials and energy-dissipation elastomers can effectively reduce shock load, yet the sharp interface between two types of materials causes discontinuous stress transfer and cracking. Here, inspired by the squid beak, we report a type of high impact-resistance gradient elastomers with large-scale modulus gradient with about three orders of magnitude (modulus range of 7 × 10³ ∼ 7 × 10⁶ Pa) and high energy dissipation (loss factor > 0.6) over a wide temperature range by diffusively introducing stiff polymers in a highly damping elastomer with controlled mechanical properties. Under the action of an external force, our gradient elastomers exhibit soft-while-stiff attributes, combining cushioning and support. In drop hammer impact tests, our gradient materials can reduce impact strength by 80 %, significantly better than commercial protective gear. It is worth mentioning that the modulus of the bottom layer matches that of the tissues for better protection.