Physical-Chemical Coupling Coassembly Approach to Branched Magnetic Mesoporous Nanochains with Adjustable Surface Roughness.

Self-assembly processes triggered by physical or chemical driving forces have been applied to fabricate hierarchical materials with subtle nanostructures. However, various physicochemical processes often interfere with each other, and their precise control has remained a great challenge. Here, in this paper, a rational synthesis of 1D magnetite-chain and mesoporous-silica-nanorod (Fe3O4&mSiO2) branched magnetic nanochains via a physical-chemical coupling coassembly approach is reported. Magnetic-field-induced assembly of magnetite Fe3O4 nanoparticles and isotropic/anisotropic assembly of mesoporous silica are coupled to obtain the delicate 1D branched magnetic mesoporous nanochains. The nanochains with a length of 2-3 µm in length are composed of aligned Fe3O4@mSiO2 nanospheres with a diameter of 150 nm and sticked-out 300 nm long mSiO2 branches. By properly coordinating the multiple assembly processes, the density and length of mSiO2 branches can well be adjusted. Because of the unique rough surface and length in correspondence to bacteria, the designed 1D Fe3O4&mSiO2 branched magnetic nanochains show strong bacterial adhesion and pressuring ability, performing bacterial inhibition over 60% at a low concentration (15 µg mL-1). This cooperative coassembly strategy deepens the understanding of the micro-nanoscale assembly process and lays a foundation for the preparation of the assembly with adjustable surface structures and the subsequent construction of complex multilevel structures.

Mesoporous TiO2 Single-Crystal Particles from Controlled Crystallization-Driven Mono-Micelle Assembly as an Efficient Photocatalyst.

Mesoporous materials with crystalline frameworks have been widely explored in many fields due to their unique structure and crystalline feature, but accurate manipulations over crystalline scaffolds, mainly composed of uncontrolled polymorphs, are still lacking. Herein, we explored a controlled crystallization-driven monomicelle assembly approach to construct a type of uniform mesoporous TiO2 particles with atomically aligned single-crystal frameworks. The resultant mesoporous TiO2 single-crystal particles possess an angular shape ∼80 nm in diameter, good mesoporosity (a high surface area of 112 m2 g-1 and a mean pore size at 8.3 nm), and highly oriented anatase frameworks. By adjusting the evaporation rate during assembly, such a facile solution-processed strategy further enables the regulation of the particle size and mesopore size without the destruction of the oriented crystallites. Such a combination of ordered mesoporosity and crystalline orientation provides both effective mass and charge transportation, leading to a significant increase in the hydrogen generation rate. A maximum hydrogen evolution rate of 12.5 mmol g-1 h-1 can be realized, along with great stability under solar light. Our study is envisaged to extend the possibility of mesoporous single crystal growth to a range of functional ceramics and semiconductors toward advanced applications.

Stepwise Monomicelle Assembly for Highly Ordered Mesoporous TiO2 Membranes with Precisely Tailored Mesophase and Porosity.

Mesoporous materials with crystalline frameworks have been acknowledged as very attractive materials in various applications. Nevertheless, due to the cracking issue during crystallization and incompatible hydrolysis and assembly, the precise control for crystalline mesoscale membranes is quite infertile. Herein, we presented an ingenious stepwise monomicelle assembly route for the syntheses of highly ordered mesoporous crystalline TiO2 membranes with delicately controlled mesophase, mesoporosity, and thickness. Such a process involves the preparation of monomicelle hydrogels and follows self-assembly by stepwise solvent evaporation, which enables the sensitive hydrolysis of TiO2 oligomers and dilatory micelle assembly to be united. In consequence, the fabricated mesoporous TiO2 membranes exhibit a broad flexibility, including tunable ordered mesophases (worm-like, hexagonal p6mm to body-centered cubic Im3̅m), controlled mesopore sizes (3.0-8.0 nm), and anatase grain sizes (2.3-8.4 nm). Besides, such mesostructured crystalline TiO2 membranes can be extended to diverse substrates (Ti, Ag, Si, FTO) with tailored thickness. The great mesoporosity of the in situ fabricated mesoscopic membranes also affords excellent pseudocapacitive behavior for sodium ion storage. This study underscores a novel pathway for balancing the interaction of precursors and micelles, which could have implications for synthesizing crystalline mesostructures in higher controllability.

Self-Healable and Robust PE/PEDOT/SWCNT Thermoelectric Composites.

With increasing popularity and great application prospects of flexible wearable electronics, organic thermoelectric (TE)materials have become one hotspot in view of energy recycling and environment protection. However, diversifying application scenarios and frequent movements impose inevitable damage to materials. Herein, the polyethylene (PE) matrix is used in compositing with poly(3,4-ethylenedioxythiophene) and single-walled carbon nanotubes, forming a unique conductive penetration network and endowing the composites with a maximal room-temperature power factor of 158.81 µW m-1 K-2 with 20 wt % of PE. The introduction of PE not only reduces thermal conductivity (out-of-plane) but also provides the composites with self-healing and good mechanical properties. The compounding method and penetration structure reported in this work are universal and enlightening in developing highly efficient TE composites with cost-effectiveness and good comprehensive properties for low-grade waste heat utilization.

Enhancing Thermoelectric Performance of Polyaniline/Single-Walled Carbon Nanotube Composites via Dimethyl Sulfoxide-Mediated Electropolymerization.

The fabrication of flexible high-performance organic/inorganic thermoelectric (TE) composite films has been a hot spot for researchers in recent years. In this work, dynamic 3-phase interfacial electropolymerization of aniline, together with physical mixing with single-walled carbon nanotubes (SWCNTs), was adopted to prepare polyaniline/SWCNT (PANI/SWCNT) TE composites. The dimethyl sulfoxide (DMSO) added into the electrochemical polymerization system affords strong capability in improving the TE performance of composite films. Moreover, varying loadings of SWCNTs can also conveniently tune the TE performance of composites. Hence, the resultant composites afford the highest power factor (PF) of 236.4 ± 5.9 µW m-1 K-2 at room temperature. This work demonstrates that the introduction of DMSO into the electrolyte and the electrochemical polymerization are highly effective in fabricating high-performance PANI/SWCNT TE composites.

Poly(3,4-ethylenedioxythiophene)/Te/Single-Walled Carbon Nanotube Composites with High Thermoelectric Performance Promoted by Electropolymerization.

Electrochemical polymerization has proven very effective in fabricating flexible organic/inorganic composite films with high thermoelectric (TE) performance. In this work, dynamic three-phase interfacial electropolymerization of 3,4-ethylenedioxythiophene (EDOT) combined with physical mixing of single-walled carbon nanotubes (SWCNT) and tellurium nanowires was employed to prepare PEDOT/Te/SWCNT thermoelectric composites. When the loadings of Te and SWCNT were changed, the electropolymerized PEDOT exhibited great capability of improving TE properties of the resultant composites with a highest electrical conductivity (σ) of 900.3 ± 20.5 S cm-1 and Seebeck coefficient (S) of 43.4 ± 0.6 µV K-1, affording maximum power factor (PF) of 169.8 ± 7.8 µW m-1 K-2 at room temperature.

Stackelberg Game-Based Power Allocation for V2X Communications.

Ultra-reliable low-latency communication (URLLC) is one of the three usage scenarios anticipated for 5G, which plays an important role in advanced applications of vehicle-to-everything (V2X) communications. In this paper, the Stackelberg game-based power allocation problem was investigated in V2X communications underlaying cellular networks. Assuming that the macro-cellular base station (MBS) sets the interference prices to protect itself from the V2X users (VUEs), the Stackelberg game was adopted to analyze the interaction between MBS and VUEs, where the former acts as a leader and the latter act as followers. For MBS, we aimed at maximizing its utility from interference revenue while considering the cost of interference. Meanwhile, the VUEs aimed at maximizing their utilities per unit power consumption. We analyzed the Stackelberg model and obtained the optimal prices for MBS and optimal transmit powers for VUEs. Simulation results demonstrated the superiority of the proposed Stackelberg game-based power allocation scheme in comparison with the traditional power allocation strategy. Meanwhile, the proposed scheme achieved a better trade-off between economic profit and power consumption.