Search

PA1212 exhibits blue fluorescence and persistent room-temperature green phosphorescence. Hydrogen-bond-constructed amide clusters play an important role in the emission. The order and extension of the hydrogen bonds regulate the luminescence process.

Targeting sustainable and eco-friendly polymer synthesis, we demonstrate here a synergistically catalyzed atom transfer radical polymerization (ATRP) induced and controlled by interplay between ball milling (BM) and piezoelectric nanoparticles (piezoNPs). BM-induced electron transfer can be achieved through piezoNPs deformation under impact force, serving as an external stimulus to mediate polymerization. The ppm level of copper loading is sufficient in fabrication of a polymer with well-defined molecular weight and low polydispersity. High-molecular-weight polymers ranging from 33 to 74 kDa were prepared successfully through DMSO-assisted grinding. Besides, its good performance on availability of water as liquid-assisted grinding additive, the recyclability of piezoNPs, and the formation of cross-linker-free composite resin make our ATRP approach a green and practical option alongside the existent heat-, electro-, and photo-induced methods.

Owing to the benefits of using natural or artificial light sources as a stimulus, photoinduced reversible-deactivation radical polymerization (photoRDRP) techniques have been recognized to be a powerful "green" platform for the preparation of well-defined polymers. However, the development of highly efficient visible light-induced photoRDRP processes in aqueous dispersed media remains a challenge due to light scattering and refraction by monomer droplets or colloidal particles. In this work, an efficient green photocatalyst, carbon quantum dots (CQDs), was introduced to visible light-mediated miniemulsion atom transfer radical polymerization (ATRP), leading to highly efficient polymerizations with reaction rates (80% monomer conversion within 1 h) much higher than in previous studies. This heterogeneous photocatalytic system is presumed to involve three catalytic cycles in (i) the aqueous phase, (ii) the oil-water interface, and (iii) the monomer droplets. The effect of different polymerization parameters on the polymerization reaction was investigated, including the amounts of surfactant and CQDs, CuBr

Anisotropic thermally conductive composites are very critical for precise thermal management of electronic devices. In this work, in order to prepare a composite with significant anisotropic thermal conductivity, polyamide 12/styrene–acrylic copolymer–boron nitride (PA12/SA–BN) composites with macro and micro double anisotropic structures were fabricated successfully using 3D printing and micro-shear methods. The morphologies and thermally conductive properties of composites were systematically characterized via SEM, XRD, and the laser flash method. Experimental results indicate that the through-plane thermal conductivity of the composite is 4.2 W/(m·K) with only 21.4 wt% BN, which is five times higher than that of the composite with randomly oriented BN. Simulation results show that the macro-anisotropic structure of the composite (caused by the selective distribution of BN) as well as the micro-anisotropic structure (caused by the orientation structure of BN) both play critical roles in spreading heat along the specified direction. Therefore, as-obtained composites with double anisotropic structures possess great potential for the application inefficient and controllable thermal management in various fields.

Broadband photoinduced electron/energy transfer RAFT (PET-RAFT) polymerization was achieved by Au/g-C3N4 complex photocatalysts.

SiQD-catalyzed visible light induced ATRP provides not only good control of polymerization, but also has the potential for application in controlled surface modification through surface grafting photoATRP (SG-ATRP) with the assistance of MPS.

Silver nanocrystal arrays had attracted much attention due to the unique plasmonic effect of their ordered nanostructure and the synergy among adjacent nanocrystals. Conventional preparation methods had several limitations, such as high cost, harsh preparation conditions, and complicated influencing factors, which could not be employed to fabricate the nanocrystal arrays in highly controlled fashion. To solve these issues, we reported ordered arrays of different Ag nanocrystals with precise control prepared by utilizing amphiphilic star-like poly(4-vinylpyridine)

Photoinduced atom transfer radical polymerization (ATRP) has been proved to be a versatile technique for polymer network formation. However, the slow polymerization rates of typical ATRP limited its application in the field of additive manufacturing (3D printing). In this work, we introduced carbon quantum dots (CQDs) for the first time to the ATRP in aqueous media and developed an ultrafast visible-light-induced polymerization system. After optimization, the polymerization could achieve a high monomer conversion (90%) within 1 min, and the polydispersity index (PDI) of the polymer was lower than 1.25. This system was then applied as the first example of ATRP for the 3D printing of hydrogel through digital light processing (DLP), and the printed object exhibited good dimensional accuracy. Additionally, the excellent and stable optical properties of CQDs also provided interesting photoluminescence capabilities to the printed objects. We deduce this ATRP mediated 3D printing process would provide a new platform for the preparation of functional and stimuli-responsive hydrogel materials.

Various piezoelectric nanomaterials were utilized in ultrasound-mediated atom transfer radical polymerization (ATRP), owing to their outstanding piezoelectric effect. However, the relationship between the morphology of those piezocatalysts and polymerization has not been clearly established. Herein, we employed different piezoelectric zinc oxide (ZnO) nanomaterials to achieve novel mechano-induced ATRP (mechano-ATRP). Based on the synergistic effect of piezoelectric properties and specific surface area, the catalytic activity of 1D ZnO nanorods (1D-ZnO NRs) with increased aspect ratio outperformed that of 0D ZnO nanoparticles (0D-ZnO NPs). Compared to the conventional ATRP system, this system exhibited extraordinary activity toward the less activated monomer acrylonitrile (67% conversion after 6 h), with a narrow molecular weight distribution (polydispersity index ∼ 1.19). Furthermore, implications of ZnO loading, copper salt amount, degree of polymerization, monomer, and solvent were also studied for the highly efficient mechano-ATRP.

The utilizing light with broadband range has attracted lots of research interest for the photo induced reversible-deactivation radical polymerization (RDRP). However, it is still a challenge for a single catalyst to simultaneously respond to various lights with highly varied wavelengths. Here, we proposed a simple strategy for the preparation of a heterogeneous photocatalyst suitable for photo induced atom transfer radical polymerization (photoATRP) under full spectrum (from UV/vis light to NIR), by combining pyridine nitrogen doped carbon dots (N-CDs) and upconversion nanoparticles (UCNPs). In the presence of these robust UCNP@SiO

Multiple and two-way reversible shape memory polymers (M/2W-SMPs) are highly promising for many fields due to large deformation, lightweight, strong recovery stress, and fast response rates. Herein, a semi-crystalline block poly(urethane-urea-amide) elastomers (PUUAs) are prepared by the copolymerization of isocyanate-terminated polyurethane (OPU) and amino-terminated oligomeric polyamide-1212 (OPA). PUUAs, composed of OPA as stationary phase and PTMEG as reversible phase, exhibit excellent rigidity, flexibility, and resilience, and cPUUA-C

A representative closely packed conjugated polyrotaxane (CPR1) is synthesized by threading polyaniline (PAN) into β-cyclodextrin (CD) macrocycles and utilized for the first time to construct an RRAM device that exhibits an outstanding resistive switching capability. The CPR1 RRAM device displays remarkable nonvolatile memory performance with an extremely high ON/OFF ratio of 10

Artificial synaptic devices and systems have become hot topics due to parallel computing, high plasticity, integration of storage, and processing to meet the challenges of the traditional Von Neumann computers. Currently, two-terminal memristors and three-terminal transistors have been mainly developed for high-density storage with high switching speed and high reliability because of the adjustable resistivity, controllable ion migration, and abundant choices of functional materials and fabrication processes. To achieve the low-cost, large-scale, and easy-process fabrication, solution-processed techniques have been extensively employed to develop synaptic electronics towards flexible and highly integrated three-dimensional (3D) neural networks. Herein, we have summarized and discussed solution-processed techniques in the fabrication of two-terminal memristors and three-terminal transistors for the application of artificial synaptic electronics mainly reported in the recent five years from the view of fabrication processes, functional materials, electronic operating mechanisms, and system applications. Furthermore, the challenges and prospects were discussed in depth to promote solution-processed techniques in the future development of artificial synapse with high performance and high integration.

Luminescent materials are indispensable for applications in lighting, displays and photovoltaics, which can transfer, absorb, store and utilize light energy. Their performance is closely related with their size and morphologies, exact atomic arrangement, and local configuration about photofunctional centers. Advanced electron microscopy-based techniques have enabled the possibility to study nanostructures with atomic resolution. Especially, with the advanced micro-electro-mechanical systems, it is able to characterize the luminescent materials at the atomic scale under various environments, providing a deep understanding of the luminescent mechanism. Accordingly, this review summarizes the recent achievements of microscopic study to directly image the microstructure and local environment of activators in lanthanide and manganese (Ln/Mn

The combination of piezoelectric material and ball milling leads to new frontiers in catalysis research. Here we used piezoelectric BaTiO3 nanoparticles as the additive for the degradation of dye pollutant in solid state in ball milling process. With the assistant of ppm level CuBr2 and H2O2, high degradation conversion (>99%) of dyes can be achieved in short time (10 min). BaTiO3 nanoparticles became temporarily highly polarized particles during BM process and generated electron-hole. These particles exhibited strong reducing properties and reduced Cu(II) into the active Cu(I) species which can catalyze H2O2 to generate highly active ·O2– to enhance the dye degradation. In addition to the general applicability for different dyes and larger scales, this BaTiO3 assist BM process was deduced to be a promising powerful platform for organic pollutant treatment in solid states.

Colloidal nanocrystal clusters (CNCs) are hierarchical nanostructure formed by clustering several nanocrystals into one nano-ensemble. In this work, novel lignosulfonate (LS)-based superparamagnetic CNCs were prepared for the first time. The strategy based on electrostatic interaction between LS, nanocrystals and charge control agent, and included multistep of surface modification, precipitation and self-assembly. With the protection of LS and blocking of CTAB, individual γ-Fe2O3 nanocrystals in the colloidal particles can keep monodisperse to form the cluster morphology. The superparamagnetic γ-Fe2O3 endowed superparamagnetic property to the CNCs, and the saturation magnetization value of CNCs increased with the increase number of nanocrystals in the LS spheres. Furthermore, the LS-based superparamagnetic CNCs showed excellent dye adsorption efficiency for different dyes, especially for positive charged cationic dyes.

Aiming at dissipating the undesired heat generated by the electronic devises during working process to the outside through a controllable way without affecting other adjacent components, novel polyamide 12 (PA12) based template composites with selectively distributed boron nitride (BN) have been explored successfully by simple and effective 3D printing technology coupled with roller-rolling method. The morphological structure, thermally conductive property as well as thermally conductive mechanism of the template composite were investigated systematically. The improved template composites showed significant localized and unidirectional thermally conductive property. And the through-plane thermal conductivity of the template composite can reach as high as 4.26 W/(m·K) with the BN content of 33.5 wt%, which is over 3 times that of the isotropic composite with the same BN content. Both of the experiment and simulated results revealed that the significantly enhanced thermally conductive property for the composites was attributed to the selectively distributed BN, which is beneficial to realize precise and controllable heat dissipation. This study sheds light on the rational design and fabrication of the high-efficiency composites with localized and unidirectional thermally conductive property for the application of thermal management system of the high-frequency and high-speed electronic devices.