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Stretchable electrodes are an essential component in soft actuator systems. In particular, Joule heating electrodes (JHEs) are required for thermal actuation systems. A highly stretchable, patternable, and low-voltage operating JHE based on hybrid layers of silver nanowires (AgNWs) and carbon nanotubes (CNTs) is reported. The conductive layers were applied on a locally pre-strained bistable electroactive polymer (BSEP) membrane to form a wrinkled conductive surface with a low resistance of 300 Ω/sq, and subsequently patterned to a serpentine trace by laser engraving. The resistance of the resulting electrode remains nearly unchanged up to ~80-90% area strain. By applying a voltage of 7 - 9 V to the electrode, the temperature of the BSEP membrane increased to more than 60 °C, well above the polymer's phase transition temperature of 46 °C, thereby lowering its modulus by a factor of 103. An electronic Braille device based on the JHEs on a BSEP membrane was assembled with a diaphragm chamber. The electrode was patterned into 3 × 2 individually addressable pixels according to the standard U.S. Braille cell format. Through Joule heating of the pixels and local expansion of the BSEP membrane using a small pneumatic pressure, the pixels deformed out of the plane by over 0.5 mm to display specific Braille letters. The Braille content can be refreshed for 20,000 cycles at the same operating voltage.

Dielectric elastomer actuators (DEAs) feature large, reversible in-plane deformation, and stacked DEA layers are used to produce large strokes in the thickness dimension. We introduce an electrophoretic process to concentrate boron nitride nanosheet dispersion in a dielectric elastomer precursor solution onto a designated electrode surface. The resulting unimorph nanocomposite dielectric elastomer (UNDE) has a seamless bilayer structure with 13 times of modulus difference. The UNDE can be actuated to large bending curvatures, with enhanced breakdown field strength and durability as compared to conventional nanocomposite dielectric elastomer. Multiple UNDE units can be formed in a simple electrophoretic concentration process using patterned electrode areas. A disc-shaped actuator comprising six UNDE units outputs large bidirectional stroke up to 10 Hz. This actuator is used to demonstrate a high-speed lens motor capable of varying the focal length of a two-lens system by 40 times.

Ambipolar transistors from low-dimensional semiconductors with high charge-transporting capability and tunable bandgap have developed rapidly in functional applications, such as neuromorphic computing, lighting, storing, and sensing. However, there are still challenges to balance procedure complexity and device performance, such as current on–off ratio, work voltage, and operational reliability. Here, we demonstrated solution-processed ambipolar ionic-gated transistors (amIGTs) from stacked heterojunctions of 1D/2D SnO2/Se composites and 2D WSe2 nanosheets, with high current on–off ratios, low work voltage, and high operational stability. The 1D/2D SnO2/Se composite, involving 1D SeNWs and 2D SnO2 nanosheets, was directly obtained by a one-step self-conversion from 2D SnSe nanosheets. We found that charge transports in SnO2/Se were greatly improved by formed efficient channels of 1D SeNWs, giving the extremely low value of subthreshold swing (SS) of reaches as low as 68 mV/dec, very close to the limitation (60 mV/dec) of "Boltzmann theory." Using the amIGTs, we achieved highly stable and operation-tunable thermal sensing, with a high sensitivity of 16%/K, high resolution of 0.1 K, and a large linear detection range of 100 K. Our results hold great implications for wide applications of the low-dimensional material-based transistors in the post-Moore era. [ABSTRACT FROM AUTHOR]

A copper-based metal-organic framework named NH2-Cu-MOF has been synthesized and utilized as an effective broad-spectrum antimicrobial material in this article. The obtained NH2-Cu-MOF exhibits satisfying antibacterial activity against both gram-positive bacteria (S. aureus and S. epidermidis) and gram-negative bacteria (E. coli and K. peneumoniae). Additionally, the biocompatibility of this NH2-Cu-MOF has been validated through animal studies, showing no significant adverse effects, thereby confirming its high biocompatibility. These findings prove that NH2-Cu-MOF has positive effects upon the treatment of bacteria-infected wounds, which holds great potential to be applied in biochemistry field. [ABSTRACT FROM AUTHOR]

Poly(l-lactide) (PLA) is a bioderived and biodegradable polymer that has limited applications due to its hard and brittle nature. Incorporation of 1,3-trimethylene carbonate into PLA, in a block copolymer fashion, improves the mechanical properties, while retaining the biodegradability of the polymer, and broadens its range of applications. However, the preparation of 1,3-trimethylene carbonate (TMC)/l-lactide (LA) copolymers beyond diblock and triblock structures has not been reported, with explanations focusing mostly on thermodynamic reasons that impede the copolymerization of TMC after lactide. We discuss the preparation of multiblock copolymers via the ring opening polymerization (ROP) of LA and TMC, in a step-wise addition, by a ferrocene-chelating heteroscorpionate zinc complex, {[fc(PPh2)(BH[(3,5-Me)2pz]2)]Zn(μ-OCH2Ph)}2 ([(fcP,B)Zn(μ-OCH2Ph)]2, fc = 1,1'-ferrocenediyl, pz = pyrazole). The synthesis of up to pentablock copolymers, from various combinations of LA and TMC, was accomplished and the physical, thermal, and mechanical properties of the resulting copolymers evaluated.

A molecular design strategy for the precise regulation of full‐color‐tunable emission organic luminescence materials is not yet systematically established for pyrene chemistry. To fabricate color‐tunable and highly‐efficiency pyrene‐based emitters, this article presents novel pyrene‐based molecules with donating‐π‐accepting structures, which exhibit bright, relatively narrow‐band FWHM emission, broad color‐tunable from deep blue (439 nm) to orange‐red (599 nm) both in solution and in the solid state. Moreover, the compounds 2a, 2d–g exhibit typical aggregation‐induced emission (AIE) characteristics, with an enhanced fluorescence quantum yield in the solid state. The experimental results indicated that the presence of the sterically bulky meta‐substituted biphenyl adopts an out‐of‐plane twist conformation, which can strengthen the rigidity of the molecular conformation and suppress the intermolecular π–π stacking in the aggregated state, resulting in an enhanced emission in the solid state. The prepared pyrene‐based AIEgens are applied as fluorescent inks to write Chinese characters and art with a vivid pattern. Thus, this article not only presents an efficient molecular strategy to construct pyrene‐based AIEgen with broad color‐tunable emission properties for practical applications, but also display a powerful combination of the strong alliance between the advanced luminescent materials, art and Chinese traditional culture. [ABSTRACT FROM AUTHOR]

As a possible countermeasure to the lack in algorithms for solving maximum regularization satisfiability problems as well as inadequate accuracy of intelligent optimization algorithms for solving maximum satisfiability problems, a discrete chaotic quantum based bat algorithm based on the bat algorithm (BA) was proposed herein. This algorithm was discretized by conversion of continuous values to discrete binary codes. By applying quantum theory, introducing quantum bit encoding and heuristic quantum mutation, the mutation is achieved by changing the probability amplitude of non optimal individuals through quantum rotation gates, solving the problems of precocity and slow convergence speed. In position update, chaotic mapping is used to replace fixed parameters, which enhances flexibility and diversity, and improves global optimization ability and solving efficiency. The experimental results show that the proposed algorithm has much higher accuracy than traditional heuristic algorithms in generating different scale examples in the stochastic regularization satisfiability problem instance generation model. At the same time, compared with the award-winning solver, it also has a certain level of competitiveness, verifying the effectiveness of the algorithm. [ABSTRACT FROM AUTHOR]

Three new pyrrolo[3,2‐b]pyrrole derivatives containing methoxyphenyl, pyrene or tetraphenylethylene (TPE) units (compounds 1–3) have been designed, synthesized and fully characterized. The aggregation‐induced emission (AIE) properties of compounds 1–3 were tested in different water fraction (fw) of tetrahydrofuran (THF). The pyrrolo[3,2‐b]pyrrole derivative 3 containing TPE units exhibited typical AIE features with an enhanced emission (∼32‐fold) in the solid state versus in solution; compounds 1 and 2 exhibited an aggregation‐caused quenching effect. In addition, the steric and electronic effects of the peripheral moieties on the emission behavior, both in solution and in the solid state, have been investigated. Moreover, pyrrolo[3,2‐b]pyrrole 1 exhibits high sensitivity and selectivity for dichloromethane and chloroform solvents, with the system displaying a new emission peak and fast response time under ultraviolet irradiation. [ABSTRACT FROM AUTHOR]

Multicellular eukaryotes produce small RNA molecules (approximately 21-24 nucleotides) of two general types, microRNA (miRNA) and short interfering RNA (siRNA). They collectively function as sequence-specific guides to silence or regulate genes, transposons, and viruses and to modify chromatin and genome structure. Formation or activity of small RNAs requires factors belonging to gene families that encode DICER (or DICER-LIKE [DCL]) and ARGONAUTE proteins and, in the case of some siRNAs, RNA-dependent RNA polymerase (RDR) proteins. Unlike many animals, plants encode multiple DCL and RDR proteins. Using a series of insertion mutants of Arabidopsis thaliana, unique functions for three DCL proteins in miRNA (DCL1), endogenous siRNA (DCL3), and viral siRNA (DCL2) biogenesis were identified. One RDR protein (RDR2) was required for all endogenous siRNAs analyzed. The loss of endogenous siRNA in dcl3 and rdr2 mutants was associated with loss of heterochromatic marks and increased transcript accumulation at some loci. Defects in siRNA-generation activity in response to turnip crinkle virus in dcl2 mutant plants correlated with increased virus susceptibility. We conclude that proliferation and diversification of DCL and RDR genes during evolution of plants contributed to specialization of small RNA-directed pathways for development, chromatin structure, and defense.