Articles in 2022

A mechanically percolated network of 2D gold nanosheets embedded within a PDMS elastomer enables the realization of elastomeric electrodes with superior mechanical sustainability and high electrical conductivity. Owing to such highly durable elastomeric electrodes facilitate the development of elastomeric electronics, including transistors, inverters, NOR, and NAND, which is expected to broaden the scope of soft electronic applications.

The β-cell microcapsules prepared by the microfluidic electrospray method were transplanted into the omentum pouch of mice for intelligent release of insulin to treat diabetes. Studies have shown that microcapsules can encapsulate cells while allowing nutrients and metabolites to enter and exit. This ability helps protect cells, improve cell activity, and reduce inflammation. In addition, the β-cell microcapsules can intelligently release insulin. The constructed living cell biosystem was further demonstrated its potential as artificial islets to be transplanted into diabetic mice omentum pouch to control blood glucose levels and thus treat diabetes of mice.

This review highlights the recent advances in fluorescence microscopic visualization of synthetic hydrogels, bio-macromolecular hydrogels, organohydrogels, and supramolecular hydrogels. Topics related to the structural changes of hydrogels, hydrogel mechanics, and super-resolution imaging of hydrogels based on fluorescence microscopy are introduced. The design concepts, imaging mechanisms, and potential applications of the novel fluorescence visualization strategies are discussed in detail. Finally, our opinions on the major challenges of current research, possible solutions, and future directions are shared.

We report that recently synthesized NaZnBi is a new dual topological insulator, with \({\Bbb Z}_2\) indices \((\nu _0;\nu _1\nu _2\nu _3) = (1;000)\) and odd mirror Chern numbers ±1, based on the first-principles calculations. NaZnBi, which crystallizes in a tetragonal structure with the P4/nmm space group, consists of ZnBi layers and embedded Na atoms. The (100) surface electronic structure exhibits the gapless surface states, which connect the valence and conduction bulk bands. These gapless surface states form the topological Dirac point at the Brillouin zone center \(\overline{\Gamma}\). This characteristic clearly shows the topological insulating phase in NaZnBi. Moreover, by applying an external magnetic field in various directions, we verify that the topological Dirac point at \(\overline {\Gamma}\) is protected by the time-reversal and mirror symmetries, and confirm that NaZnBi belongs to the class of dual topological insulators.

The “molecular knitting method” improves toughness and Young’s modulus. We prepared dual cross-network (DC) elastomers with a knitting structure and single movable cross-network elastomers with penetrating polymers (SCP elastomers) by swelling the single movable cross-network (SC) elastomers in liquid monomers. The DC elastomers showed a high toughness and a high Young’s modulus. SAXS indicated that the DC elastomers exhibited heterogeneity at the nanoscale. The DC elastomers showed a significantly broader relaxation time distribution than the SC and SCP elastomers. Thus, the nanoscale heterogeneity and broader relaxation time distribution were important to increase toughness.

Despite extensive previous research, the suppression in phonon conduction at the nanoscale still calls into questions on the interaction of phonons with various sources of boundary scatterings. In this work, a combination of Boltzmann transport model and the experiments finds that the bridges contribute to phonon mean free paths proportional to its volume fraction despite its negligible contribution to net heat flux. A statistical analysis of boundary scattering reveals that transport characteristics of phonon evolves from Brownian motion to Lévy walk due to phonons trapped within the bridges.

In this work, we systematically study heat conduction in SiC nanostructures, including nanomembranes, nanowires, and phononic crystals. Our measurements show that the thermal conductivity of nanostructures is several times lower than that in bulk and the values scale proportionally to the narrowest dimension of the structures. Additionally, we probed phonon mean free path and coherent heat conduction in these nanostructures. Our theoretical model links the observed suppression of heat conduction with the surface phonon scattering, which limits the phonon mean free path and thus reduces the thermal conductivity.

For the emergent colossal, reversible barocaloric effect in organic–inorganic perovskite hybrids (CH₃–(CH₂)_n−1–NH₃)₂MnCl₄ (n = 9, 10), we successfully grew a single crystal, and the underlying mechanism was determined by high-resolution SC-XRD, IR spectroscopy and DFT calculations. The drastic transformation of organic chains confined to the metallic frame from ordered rigidity to disordered flexibility is responsible for the large phase-transition entropy, which is comparable to the melting entropy of organic chains. The result provides new insights into designing novel barocaloric materials by utilizing the disordering of organic chains of organic–inorganic hybrid materials.

A rare-earth intermetallic La-Ce-Fe-Si-H has been directly measured to cool 8 K when it is under a 1 kbar pressure. This barocaloric strength significantly outperforms those in previously reported phase-transitioned alloys. A multifield-dependent neutron diffraction has revealed that the large isotropic transition volume change for La-Ce-Fe-Si-H plays a crucial role in exploring the giant barocaloric effect.

(Left, above) Schematic diagram describing the process of the Au implantation into the Dirac semimetal (DSM) Bi_0.96Sb_0.04. (Left, below) Positive longitudinal magnetic resistance (LMR) is observed in the crystal without ion implantation, but negative LMR behavior becomes apparent for ϕ_G ≥ 3.2 × 10¹⁶ Au cm⁻² (≡ ϕ_C, critical implant fluence), and reaches a maximum for ϕ_G = 8.0 × 10¹⁶ Au cm⁻². (Middle) Quantum oscillation parameters for the β Fermi pockets showing abrupt changes near ϕ_C, typical of phase transition. No such behavior is observed for the α Fermi pockets. (Right) A drastic change in the Raman spectra is observed for ϕ_G ≥ ϕ_C. In particular, a new peak appears at 85.7 cm⁻¹, between the well-known Raman modes, suggesting that the inversion symmetry breaking in the crystal occurred for ϕ_G ≥ ϕ_C, resulting in the transition of the DSM to a Weyl semimetal.

Clay nanosheets (CNSs) of synthetic hectorite have been used for synthesizing advanced functional gels that exhibit high mechanical toughness and many unprecedented characteristics, such as cell harvesting, instant strong adhesion, and self-healing. Upon varying the pH and salt concentration, the aqueous CNS dispersions were found to exhibit a maximum viscosity accompanied by gelation, in addition to large and complex time-dependent viscosity changes in the static state. Such anomalous viscosity dynamics depended on the types of clay and acid (salt), temperature, number of repetitions, and agitation conditions; their mechanisms were also discussed in terms of variations in the CNS microstructures.

It is the first work demonstrating the modulating opto-electrical signals of organic semiconductors by the liquid crystal properties. Through flipping the anisotropic surface treatment-based sandwich cells, the liquid crystal organic semiconductor responds to the given surface anchoring condition with temperature gradient, showing tunable molecular orientation with the corresponding charge carrier mobility of organic field-effect transistors.

Smart hydrogels with wide visible color tunability and highly tunable color saturations and transmittances are created. The hydrogels with flexible light-interacting configuration changes, can harvest energy from selected wavelengths of visible light to display complementary colors across a wide visible range. The hydrogels are used as optical filters and colorimetric sensors to demonstrate their versatility.

We demonstrate the early diagnosis of cracked tooth syndrome (CTS) by imaging the microcracks on a tooth in the closed mouth condition using a mechanoluminescence (ML) phosphor and a stretchable and self-healable photodetector array that can conformably cover a single tooth. This method does not require sophisticated equipment and hence will be useful in the early diagnosis of CTS. To the best of our knowledge, this is the first report on the use of ML for the detection of the position of tooth cracks.

In this study, regulating composition and morphology of the trimetallic Co-Ni-Ru sulfoselenide and bimetallic sulfoselenide nanosheets are designed for efficient and durable OER electrocatalysts. The sheet structure has a large specific surface area to promote the contact between the catalyst and the electrolyte. Density functional theory (DFT) calculations show that appropriate Ru and Ni doping simultaneously (Co-Ni-Ru-S-Se) can increase the density of states of the Fermi level, resulting in excellent charge density and low intermediate adsorption energy.

The multifunctional soft sensors attached to the glove are capable of simultaneously sensing six stimuli, including pressure, bending strain, temperature, proximity, UV light, and humidity, with high accuracy and without interference among the respective built-in components. The sensor is fabricated via supersonic spraying using silver nanowires, carbon nanotubes, zinc oxide, and conducting polymer poly(3,4-ethylenedioxythiophene) polystyrene sulfonate.

Photoconductivity response of electrophoretically deposited hexamolybdenum cluster complex.

Composition phase diagram of Eu_1−xSr_xMn_1−zSb₂ on the structural and magnetic transitions, Eu–Mn moment angle α, and nontrivial Berry phase is presented. A doping of nonmagnetic Sr on Eu site breaks lattice symmetry and induces various Eu spin reorientations that are coupled to quantum transport properties of the relativistic fermions generated the 2D Sb layers. Eu_1−xSr_xMn_1−zSb₂ is therefore a new unique material platform for exploring the Dirac band tuning by magnetism. Our study suggests nonmagnetic element doping to the rare-earth element site may be an effective strategy to generate topological electronic states and new magnetic states in layered compounds involving spatially separated rare-earth and transition metal layers.

A multifunctional plasmonic nanoplatform inspired from chameleon skin is developed for the purpose of glucose sensing applications in body fluids. Fabricated nanoplatforms consisted of two outer layers of fully-crosslinked P(NIPAAm-co-NIPMAAm) hydrogel embedded with plasmonic silver nanocubes, while the inner layer is an electrospun nanofibrous mat of PCL/PEO. Morphological and optical investigation on layers of the platform as well as the whole structure shows the well-fabricated structure offering a compact and stable device. The platform provides fast photothermal-responsivity, mechanical and antibacterial properties as well as sensing features, which can be used to anticipate glucose levels in body fluids in both ranges of healthy and diabetic.