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With the rapid development of modern industry, it is urgently needed to measure the biotoxicity of complex chemicals. Microbial electrochemical biotoxicity sensors are an attractive technology; however, their application is usually limited by their stability and reusability after measurements. Here, we improve their performance by encapsulating the electroactive biofilm with polydopamine (PDA), and we evaluate the improvement by different concentrations of heavy metal ions (Cu2+, Ag+, and Fe3+) in terms of inhibition ratio (IR) and durability. Results indicate that the PDA-encapsulated sensor exhibits a more significant detection concentration than the control group, with a 3-fold increase for Cu2+ and a 1.5-fold increase for Ag+. Moreover, it achieves 15 more continuous toxicity tests than the control group, maintaining high electrochemical activity even after continuous toxicity impacts. Images from a confocal laser scanning microscope reveal that the PDA encapsulation protects the activity of the electroactive biofilm. The study, thus, demonstrates that PDA encapsulation is efficacious in improving the performance of microbial electrochemical biotoxicity sensors, which can extend its application to more complex media. [ABSTRACT FROM AUTHOR]

As the understanding of natural gas hydrates as a vast potential resource deepens, their importance as a future clean energy source becomes increasingly evident. However, natural gas hydrates trend towards secondary generation during extraction and transportation, leading to safety issues such as pipeline blockages. Consequently, developing new and efficient natural gas hydrate inhibitors has become a focal point in hydrate research. Kinetic hydrate inhibitors (KHIs) offer an effective solution by disrupting the nucleation and growth processes of hydrates without altering their thermodynamic equilibrium conditions. This paper systematically reviews the latest research progress and development trends in KHIs for natural gas hydrates, covering their development history, classification, and inhibition mechanisms. It particularly focuses on the chemical properties, inhibition effects, and mechanisms of polymer inhibitors such as polyvinylpyrrolidone (PVP) and polyvinylcaprolactam (PVCap). Studies indicate that these polymer inhibitors provide an economical and efficient solution due to their low dosage and environmental friendliness. Additionally, this paper explores the environmental impact and biodegradability of these inhibitors, offering guidance for future research, including the development, optimization, and environmental assessment of new inhibitors. Through a comprehensive analysis of existing research, this work aims to provide a theoretical foundation and technical reference for the commercial development of natural gas hydrates, promoting their safe and efficient use as a clean energy resource. [ABSTRACT FROM AUTHOR]

Polymer-based actuators have gained extensive attention owing to their potential applications in aerospace, soft robotics, etc. However, poor mechanical properties, the inability of multi-stimuli response and programmable deformation, and the costly fabrication procedure have significantly hindered their practical application. Herein, these issues are overcome via a simple and scalable one-step molding method. The actuator is fabricated by hot-pressing commercial unidirectional carbon fiber/epoxy prepregs with a commodity PC membrane. Notable CTE differences between the CF and PC layers endow the bilayer actuator with fast and reliable actuation deformation. Benefiting from the high strength of CF, the actuator exhibits excellent mechanical performance. Moreover, the anisotropy of CF endows the actuator with design flexibility. Furthermore, the multifunction of CF makes the actuator capable of responding to thermal, optical, and electrical stimulation simultaneously. Based on the bilayer actuator, we successfully fabricated intelligent devices such as light-driven biomimetic flowers, intelligent grippers, and gesture-simulating apparatuses, which further validate the programmability and multi-stimuli response characteristics of this actuator. Strikingly, the prepared gripper possesses a grasping capacity approximately 31.2 times its own weight. It is thus believed that the concept presented paves the way for building next-generation robust robotics. [ABSTRACT FROM AUTHOR]

Polyether ether ketone (PEEK) is esteemed as a high-performance engineering polymer renowned for its exceptional mechanical properties and thermal stability. Nonetheless, the majority of polymer-based lubricating materials fail to meet the contemporary industrial demands for motion components regarding high speed, heavy loading, temperature resistance, and precise control. Utilizing 3D printing technology to design and fabricate intricately structured components, developing high-performance polymer self-lubricating materials becomes imperative to fulfill the stringent operational requirements of motion mechanisms. This study introduces a novel approach employing 3D printing technology to produce PEEK with varying filling densities and conducting in situ synthesis of zeolitic imidazolate framework (ZIF-8) nanomaterials on its surface to enhance PEEK's frictional performance. The research discusses the synthetic methodology, characterization techniques, and tribological performance evaluation of in situ synthesized ZIF-8 nanomaterials on PEEK surfaces. The findings demonstrate a significant enhancement in frictional performance of the composite material under low-load conditions, achieving a minimum wear rate of 4.68 × 10−6 mm3/N·m compared to the non-grafted PEEK material's wear rate of 1.091 × 10−5 mm3/N·m, an approximately 1.3 times improvement. Detailed characterization and analysis of the worn surface of the steel ring unveil the lubrication mechanism of the ZIF-8 nanoparticles, thereby presenting new prospects for the diversified applications of PEEK. [ABSTRACT FROM AUTHOR]

In order to examine the impact of structural and thermal scale parameters on thermoelastic vibrations of Euler-Bernoulli nanobeams, this article intends to provide a size-dependent generalized thermoelasticity model with the help of nonlocal strain gradient theory (NSGT) in conjunction with dual-phase-lag (DPL) heat conduction model. To highlight the role of each scale parameter in size-dependent motion and heat conduction equations, normalized forms of these nonclassical coupled thermoelastic equations are extracted by introducing and exploiting some dimensionless parameters. By exploiting power series expansion as a general solution for arbitrary boundary conditions, system of partial differential equations reduces to system of ordinary differential equations in time domain. The Laplace transform is then utilized to attain the analytical solution of this set of differential equations. By conducting a case study on a hinged-hinged nanobeam, with the aim of illustrating the impact of nonclassical structural and thermal parameters on thermoelastic vibrations, size-dependent numerical results are compared with those estimated by classical elasticity theory and heat conduction model. Meaningful disparity between classical and nonclassical results reveals the pivotal role of scale parameters in realistic assessment of thermoelastic behavior of nanobeams. Outcomes also indicate that corresponding to the relationship between the magnitudes of two scale parameters of NSGT, the nonclassical model of nanobeam can exhibit either softening or hardening behavior compared to the classical one. This affirms the ability of NSGT to justify both stiffness softening and stiffness hardening phenomenon in nanostructures. [ABSTRACT FROM AUTHOR]

In this paper, polylactic acid porous materials were prepared by a fused deposition modeling 3D printing method. Then, a combination of methyl ethyl ketone (MEK) solution etching containing hydrophobic nano‐silica (HN‐SiO2) and low surface energy fluorosilane modification was used to obtain the samples with different wettability. The effect of immersion time in MEK solution and HN‐SiO2 content on the wettability of porous samples was investigated. Finally, the sample with the highest contact angle and extremely low sliding angle was selected for the oil/water separation test. The separation efficiency of oil/water separators with hole side lengths of 0.8, 1.0, and 1.2 for five different oil/water mixtures was investigated. The results show that the oil/water separator with a hole side length of 1.0 mm has a better primary separation effect. With the increase of the hole size of the oil–water separator, the effect of multiple separations is unfavorable. The oil/water separator with hole side length of 0.8 mm has repeatable oil/water separation performance many times. This research provides a new idea for the application of the oil/water separator with a hole side length greater than 0.6 mm printed by an ordinary, inexpensive, low‐precision fusion 3D printer. [ABSTRACT FROM AUTHOR]

Microcellular nanocomposite foams based on thermoplastic polyurethane (TPU) and organically modified layered clays were prepared via an efficient foaming method, microcellular injection molding (MIM). The morphology of the nanoclays was characterized by X‐ray diffraction (XRD) and transmission electron microscopy. The results revealed that the layered nanoclays in the nanocomposite foams achieved a well dispersed morphology within the cell walls due to the MIM foaming process. Postburn SEM images showed that TPU/NC10 foam (with 10 wt% nanoclay) was able to maintain its foam porosity, original shape, and microcellular structure due to the synergistic effects of its microcellular structure and the fully dispersed nanoclays. Thermal stability and flame resistance were assessed by thermogravimetric analysis (TGA) and microscale combustion calorimetry, respectively. TGA results indicated that the nanocomposite foams had a significant decline in the thermal degradation rate compared to the unfilled TPU/NR foam. The flame resistance tests showed that the heat release capacity (HRC) of TPU/NC10 foams was substantially lower (27% lower) than that of the unfilled TPU/NR foam. The char yield of the TPU/NC10 foam was 19.14%, which was almost 18 times higher than that of the unfilled TPU/NR foam. With the presence of the microcellular structure, the HRC values decreased from 266.8 J/g k for solid TPU/NC10 to 235.5 J/g k for TPU/NC10 foams. This work combines two flame retardant mechanisms—the thermal barrier effect of the nanoclay layers and the microcellular self‐intumescing system—in the nanocomposite foams. Our study also provides substantial motivation to produce novel, environmentally‐benign, and flame‐retardant TPU foam using microcellular injection molding. POLYM. COMPOS., 39:E1429–E1440, 2018. © 2017 Society of Plastics Engineers [ABSTRACT FROM AUTHOR]