Npg Asia Materials最新文献

Shape-memory polymers (SMPs) are smart materials that have gained significant attention in recent years owing to their widespread application in smart structures and devices. Digital light processing (DLP), a vat-photopolymerization-based technique, is a significantly faster technology for printing a complete layer in a single step. The current study reports a facile and fast method for the 3D printing of SMP-based smart structures using a DLP 3D printer and a customized resin. A liquid crystal (LC, RM257) was combined with the resin to introduce shape-memory properties. The combination of LCs in photocurable resin provides the opportunity to directly 3D-print thermoresponsive structures, avoiding the complexity of SMP resin preparation. The structures were printed with different geometries, and the shape-memory response was measured. Lattice structures were fabricated and programmed to obtain tunable mechanical properties. Furthermore, the strain-sensing response was measured to demonstrate the utility of these lattice structures as smart patches for joint-movement sensing. The SMPs can be prepared conveniently and can potentially be used for various applications, such as smart tools, toys, and meta-material sensors.

Ionogels are crosslinked networks—typically polymeric networks—swollen with ionic liquids. The unique properties of ionogels, such as nonvolatility, ionic conductivity, nonflammability, and high thermal and electrochemical stability, make them promising for a variety of applications. Examples include sensors, adhesives, energy storage devices, and ionotronics. While many ionogels require complex syntheses and suffer from poor mechanical properties, simpler strategies are emerging to produce tough ionogels, thereby improving the durability, enabling 3D printing, and broadening the application space of ionogels. This perspective highlights promising applications and future opportunities of ionogels.

Osmotic energy generation with reverse electrodialysis through membranes provides a worldwide free energy resource. Photo-driven proton transport in photosynthesis supplies basal energy for plants and living organisms on the planet. Here, we utilized aramid nanofiber (ANF) semiconductor-based membranes to enable light-driven proton transport for osmotic energy generation. Under unilateral illumination, the light-driven proton transport system converted light energy into electrical energy and showed wavelength- and intensity-dependent transmembrane potentials and currents. Interestingly, the synergistic effects of simultaneous illumination and pressure provided a five-fold increase in the voltage and a three-fold increase in the current relative to pressure alone. Density functional theory calculations and spectroscopic measurements demonstrated that the ANF and photoinduced electrons enabled proton transport during illumination and generated a transmembrane potential and current. The light-driven proton transport system supports the development of devices with flexible and stable ANF membranes.

Transparent conductors with electromagnetic shielding capabilities (TC-EMS) are rare, despite their significant potential for creating new functionalities in energy and military applications. Here, we investigate the potential of La-doped BaSnO₃ (BLSO) for TC-EMS since its epitaxial film has been known to have low sheet resistance and high visible transmittance. However, films grown on industrially practical Al₂O₃ substrates exhibit a sheet resistance three orders of magnitude higher than that of reported films grown on perovskites. Here, this problem is addressed by templating a BaZrO₃/MgO bilayer on (0001)-oriented Al₂O₃ substrates to yield single-crystalline BLSO epitaxial films. The absence of grain boundaries in the epitaxial films minimizes the electron scattering. Due to the affirmative correlation between the conductivity and crystallinity, 5% La doping is optimal among the 5−20% La concentrations studied; these 480-nm-thick films have the highest crystallinity and the lowest sheet resistances of ~28 Ω ▯⁻¹; this value is similar to that of single-crystalline levels. Due to their very high transmittances (~82% in a range 400−1000 nm) and effective X-band electromagnetic shielding (~18.6 dB), the BLSO epitaxial films grown on Al₂O₃ have great potential to be used for inexpensive TC-EMS applications.

Controlling molecular spin quantum bits optically offers the potential to effectively reduce decoherence and raise the working temperature of quantum computers. Here, exchange interactions and spin dynamics, as mediated by an optically driven triplet state, are calculated for a molecule that consists of a pair of radicals and represents a potential quantum-circuit building block. Consistent with the previous experimental observation of spin coherence induced by the triplet state, our work demonstrates an optically driven quantum gate operation scheme in a molecule. A technological blueprint combining a two-dimensional molecular network and programmable nanophotonics, both of which are sufficiently developed, is proposed. We thus realize computational exploration of chemical databases to identify suitable candidates for molecular spin quantum bits and couplers to be hybridized with nanophotonic devices. The work presented here is proposed to realize a new approach for exploring molecular excited states and click chemistry, toward advancing molecular quantum technology.

Residual stress engineering is widely used in the design of new advanced lightweight materials. For metallic glasses, attention has been given to structural changes and rejuvenation processes. High-energy scanning X-ray diffraction strain mapping reveals large elastic fluctuations in notched metallic glasses after deformation under triaxial compression. Microindentation hardness mapping hints at a competing hardening–softening mechanism after compression and reveals the complementary effects of stress and structure modulation. Transmission electron microscopy proves that structure modulation and elastic heterogeneity distribution under room temperature deformation are related to shear band formation. Molecular dynamics simulations provide an atomistic understanding of the confined deformation mechanism in notched metallic glasses and the related fluctuations in the elastic and plastic strains. Thus, future focus should be given to stress modulation and elastic heterogeneity, which, together with structure modulation, may allow the design of metallic glasses with enhanced ductility and strain-hardening ability.

The Bouligand structure found in the dactyl club of mantis shrimps is known for its impact resistance. However, Bouligand-inspired reinforced composites with 3D shapes and impact resistance characteristics have not yet been demonstrated. Herein, direct ink writing was used to 3D print composites reinforced with glass microfibers assembled into Bouligand structures with controllable pitch angles. The energy absorption levels of the Bouligand composites under impact were found to surpass those of composites with unidirectional microfiber alignment. Additionally, the Bouligand composites with a pitch angle of 40° exhibited a maximum energy absorption of 2.4 kJ/m², which was 140% higher than that of the unidirectional composites. Furthermore, the characterization of the topography of the fractured surface, supplemented with numerical simulations, revealed a combination of crack twisting and crack bridging mechanisms. Flexural tests conducted on the composites with a pitch angle of 40° revealed that these composites had the strongest properties, including a flexural strength of 36.9 MPa, a stiffness of 2.26 GPa, and energy absorption of 8 kJ/m². These findings are promising for the microstructural design of engineered composites using direct ink writing for applications in aerospace, transportation, and defense.