Engineered cementitious composites (ECCs) are potentially useful structural reinforcement and repair materials. However, owing to their high costs and carbon emissions, they are not used extensively. ...To control these carbon emissions and costs, recycled fly ash cenospheres (FACs) and high-strength polyethylene (PE) fibers are used here to explore the possibility of developing green lightweight ECCs (GLECCs). A series of experiments was conducted to test the physical and mechanical properties of the developed GLECC and to evaluate the possibility of developing an GLECC. The crack width development of the GLECC was also analyzed using the digital image correlation method. The experimental results indicate the following: (1) The increase in FAC content and the decrease in PE content worsened the performance of GLECCs, but the resulting GLECCs still had significant strain-hardening properties; (2) The performance and costs of GLECCs can be balanced by adjusting the amount of FAC and PE. The maximum amount of FACs attainable is 0.45 (FAC/binder), and the required amount of PE fibers can be reduced to 1%. As a result, the cost was reduced by 40% and the carbon emission was reduced by 36%, while the compressive strength was greater than 30 MPa, the tensile strength was greater than 3.5 MPa, and the tensile strain was nearly 3%. (3) The width of the crack was positively correlated with the FAC content and negatively correlated with the fiber content. In the 0.8% strain range, the average crack width can be controlled to within 100 μm and the maximum crack width can be controlled to within 150 μm, with the performance still meeting the requirements of many applications.
A polyterpyridinyl building block-based nutlike hexagonal bismetallo architecture with a central hollow Star of David was assembled by a stepwise strategy. This nanoarchitecture can be viewed as a ...recursive mathematical form that possesses a supramolecular corner-connected cyclic structure, i.e., a triangle or rhombus at various levels of scale or detail. The key metallo-organic ligand (MOL) with four uncomplexed free terpyridines was obtained by a final Suzuki cross-coupling reaction with a tetrabromoterpyridine Ru dimer. The molecular metallorhombus was prepared by reacting the MOL with a 60° bis-terpyridine and Fe2+. The giant hollow hexagonal nut with a diameter of more than 11 nm and a molecular weight of ca. 33 kDa was obtained in near-quantitative yield by mixing the two types of multi-terpyridine ligands with Fe2+. The supramolecular architecture was characterized by NMR (1H and 13C), 2D NMR (COSY and ROESY), and DOSY spectroscopies, high-resolution electrospray ionization mass spectrometry, traveling-wave ion mobility mass spectrometry, and transmission electron microscopy.
With the improvement in people’s living standards, the development and application of smart textiles are receiving increasing attention. In this study, a carbon nanosurface was successfully coated ...with a SiO2 layer to form C@SiO2 nanomaterials, which improved the dispersion of carbon nanomaterials in an aqueous solution and enhanced the absorption of light by the carbon nanoparticles. C@SiO2 nanoparticles were coupled on the surface of silk fabric with the silane coupling agent KH570 to form C@SiO2 nanosilk fabric. The silk fabric that was subjected to such surface modification was endowed with a special photothermal function. The results obtained with scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), and infrared spectroscopy (FTIR) showed that C@SiO2 nanoparticles were successfully modified on the surface of the silk fabric. In addition, under the irradiation of near-infrared light with a power of 20 W and a wavelength of 808 nm, the C@SiO2 nanosilk fabric experienced rapid warming from 23 °C to 60 °C within 30 s. After subjecting the functional fabric to hundreds of photothermal experiments and multiple washes, the photothermal efficiency remained largely unchanged and proved to be durable and stable. In addition, the thermogravimetric (TG) analysis results showed that the C@SiO2 nanoparticles contributed to the thermal stability of the silk fabric. The UV transmittance results indicated that C@SiO2 nanofabric is UV-resistant. The silk modification method developed in this study is low-cost, efficient, and environmentally friendly. It has some prospects for future applications in the textile industry.
Coordination‐driven self‐assembly has led to the formation of various aesthetical polyhedrons and compounds with advanced functions. Whereas two‐dimensional supramolecules with complex and giant ...skeletons are plentiful, the constructions of polyhedrons are limited by using basic polygons as the panels. Herein, we report the modular synthesis of a tessellated triangle and tessellated octahedron with metal‐organic modules as the panels and formed via template‐driven self‐assembly. These architectures have diameters on the order of 10.9 nm and molecular weights greater than 84 kDa. Interestingly, fiber and spherical‐like nanostructures could be formed from the tessellated triangles and octahedrons, respectively, through hierarchical self‐assembly. In addition, after hybridization with carbon nanotubes, the supramolecules exhibit electrochemical reduction activity for CO2 to CO.
The self‐assembly of a tessellated triangle T1 and the construction of a tessellated octahedron O1 containing metal‐organic modules as the panels are demonstrated. O1 has a diameter on the order of 10.9 nm and a molecular weight greater than 84 kDa. After hybridization with carbon nanotubes, the supramolecules exhibit electrochemical reduction activity for CO2 to CO.
Three generations of metalated trigonal supramolecular architectures, so‐called metallo‐triangles, were assembled from terpyridine (tpy) complexes. The first generation (G1) metallo‐triangles were ...directly obtained by reacting a bis(terpyridinyl) ligand with a 60° bite angle and ZnII ions. The direct self‐assembly of G2 and G3 triangles by mixing organic ligands and ZnII, however, only generated a mixture of G1 and G2, as well as a trace amount of insoluble polymer‐like precipitate. Therefore, a modular strategy based on the connectivity of ⟨tpy−Ru2+−tpy⟩ was employed to construct two metallo‐organic ligands for the assembly of G2 and G3 Sierpiński triangles. The metallo‐organic ligands LA and LB with multiple free terpyridines were obtained through Suzuki cross‐coupling of the RuII complexes, and then assembled with ZnII or CdII to obtain high‐generation metallo‐triangular architectures in nearly quantitative yield. The G1–G3 architectures were characterized by NOESY and DOSY NMR spectroscopy, ESI‐MS, TWIM‐MS, and transmission electron microscopy.
Molecular Sierpiński triangles were assembled from rigid, puzzle‐like metallo‐organic ligands. As the self‐assembly of the second‐ and third‐generation (shown) Sierpiński triangles provided only product mixtures, a modular strategy based on the connectivity of tpy−RuII−tpy was developed to construct two metallo‐organic ligands for the assembly of these triangles.
Despite many cases of textile-reinforced engineered cementitious composites (TR-ECCs) for repairing and strengthening concrete structures in the literature, research on lightweight engineered ...cementitious composites (LECC) combined with large rupture strain (LRS) textile and the effect of textile arrangement on tensile properties is still lacking. Therefore, this paper develops textile-reinforced lightweight engineered cementitious composites (TR-LECCs) with high strain characteristics through reinforcement ratio, arrangement form, and textile type. The study revealed that, by combining an LRS polypropylene (PP) textile and LECC, TR-LECCs with an ultimate strain of more than 8.0% (3–4 times that of traditional TR-ECCs) could be developed, and the PP textile’s utilization rate seemed insensitive to the enhancement rate. The basalt fiber-reinforced polymer (BFRP) textile without epoxy resin coating had no noticeable reinforcement effect because of bond slip; in contrast, the BFRP grid with epoxy resin coating had an apparent improvement in bond performance with the matrix and a better reinforcement effect. The finite element method (FEM) verified that a concentrated arrangement increased the stress concentration in the TR-LECC, as well as the stress value. In contrast, a multilayer arrangement enabled uniform distribution of the stress value and revealed that the weft yarn could help the warp yarn to bear additional tensile loads.
The double‐ or triple‐decker 3D metallo‐hexagons were obtained by self‐assembly of multitopic tris‐terpyridines with Cd2+ ions in near‐quantitative yield. Comprising up to 72 ionic pairs, the ...multiple spoked wheels display characteristic reversible gelation properties under thermodynamic conditions. The supramolecular metallo‐nanoarchitectures were characterized by 1H NMR, 2D NMR (COSY and NOESY), and diffusion‐ordered spectroscopy (DOSY) and HR‐ESI‐MS, traveling‐wave ion mobility mass spectrometry (TWIM‐MS), TEM, and AFM. For the first time, the self‐assembly of 45 units at once was demonstrated to yield exceptional giant triple‐decker hexagons of up to circa 42 000 Da.
Big wheel keep on turning: Giant triple‐decker 3D metallohexagons were assembled from triple tris‐terpyridines and Cd2+ ions. Self‐assembly of 45 units at once yields exceptional metalloorganic hexagons with a molecular weight of circa 42 000 Da. Comprising up to 72 ion pairs, the molecular spoked wheels undergo characteristic reversible gelation under thermodynamic conditions.
Five- and six-pointed star structures occur frequently in nature as flowers, snow-flakes, leaves and so on. These star-shaped patterns are also frequently used in both functional and artistic ...man-made architectures. Here following a stepwise synthesis and self-assembly approach, pentagonal and hexagonal metallosupramolecules possessing star-shaped motifs were prepared based on the careful design of metallo-organic ligands (MOLs). In the MOL design and preparation, robust ruthenium-terpyridyl complexes were employed to construct brominated metallo-organic intermediates, followed by a Suzuki coupling reaction to achieve the required ensemble. Ligand LA (VRu
X, V=bisterpyridine, X=tetraterpyridine, Ru=Ruthenium) was initially used for the self-assembly of an anticipated hexagram upon reaction with Cd
or Fe
; however, unexpected pentagonal structures were formed, that is, Cd
LA
and Fe
LA
. In our redesign, LB V(Ru
X)
was synthesized and treated with 60° V-shaped bisterpyridine (V) and Cd
to create hexagonal hexagram Cd
V
LB
along with traces of the triangle Cd
V
. Finally, a pure supramolecular hexagram Fe
V
LB
was successfully isolated in a high yield using Fe
with a higher assembly temperature.
The amalgamation of different components into a giant and intricate structure that makes quantitative and spontaneous assembly through molecular design is indispensable but challenging. To construct ...novel metallo-supramolecular architectures, here we present an architectural design principle based on multicomponent self-assembly. Using a carefully designed hexatopic terpyridine-based metallo-organic ligand (MOL), Ru
T
K, we report on the formation of supramolecular trapezoid Zn
Ru
T
KV
, hollow hexagon Zn
Ru
T
K
K
, and giant star-shaped supramolecule Zn
Ru
T
K
Ru
X
V
, all of which were assembled by one-pot, nearly quantitative assembly of Ru
T
K with the ditopic 60°-directed bisterpyridine V, tetrakisterpyridine K, and MOL Ru
X
V, respectively. The complementary ligands were selected on the basis of the size- and shape-fit principles, actually similar to the mortise-tenon joint that aligns and locks the two complementary wood components. This strategy is expected to open the door to sophisticated designer supramolecules and nonbiological materials. The multivalent connections within the mutual ligands give rise to the formation of stable assemblies, which are unambiguously characterized by NMR, ESI-MS, TWIM-MS, and TEM analyses.
Stable laser emission with ultra-narrow linewidth plays an important role in making fundamental scientific breakthroughs. Here, we propose and demonstrate a new technique for the generation of an ...ultra-narrow linewidth and highly stable laser based on stimulated Brillouin scattering in combination with a frequency-shifted optical injection locking mechanism. The laser performance is characterized via a delayed self-heterodyne interference system, where the white frequency noise floor is ∼20 mHz2/Hz, corresponding to a fundamental linewidth of about 63 mHz. The maximum deviation in the output power is less than 1.5% over more than 10 min. The operation of the laser can be stabilized without the need for active optoelectronic feedback. The scheme presented in this work enables narrow linewidth and stable single-frequency fiber lasers in a robust and efficient way, which has shown promising potential for many applications.
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