Structural diversity in Cu(II) and Cd(II) coordination complexes with 4-amino-1,2,4-triazole ligand

The syntheses and structures of the series of metal complexes, namely [CuCl₂(L)₂·H₂O)]_n (L = 4-amino-1,2,4-triazole), 1; {[Cu(L)₄][ClO₄]₂.H₂O}_n, 2; and [Cd₂Cl₄(L)₂.2H₂O]_n, 3 are reported. These were prepared by the self-assembly of Cu(II) and Cd(II) salts with L in MeOH/H₂O system. All these complexes have been characterized by elemental analysis, IR spectrum, and single crystal X-ray diffraction. Complexes 1–2 show 1-D polymeric infinite chains, while complex 3 shows 2D pleated net. The anions Cl⁻ in complexes 1 and 3 act as bridging or terminal ligands to the metal atoms while the ClO₄⁻ anions in 2 are not coordinated to the metal centers.     

Investigation and feed-forward neural network-based estimation of dyeing properties of air plasma treated wool fabric dyed with natural dye obtained from Hibiscus sabdariffa

In the colouring processes of textile products, more environmentally friendly chemicals and finishing methods should be used instead of conventional ones that harm the environment every day, so that alternative realistic ways to protect nature, both academically and industrially, could be possible. Due to some inconveniences caused by synthetic dyes that are widely used today, in this study, ultrasonic dyeing of wool fabric with Hibiscus sabdariffa was carried out after environmental-friendly air vacuum plasma application which increased the absorption of the dyes into the textile material. According to the performance results, colour strengths of the wool fabrics were increased significantly. Surface morphology analysis was carried out and etching effects of air vacuum plasma treatment were clearly seen on the micrographs of the treated wool fabrics. An environmental-friendly green process was achieved through this study and it was concluded that vacuum air plasma treatment could be an alternative green-process as a pretreatment to increase the dye up-take of natural dyeing treatment. Moreover, in this study, a feed-forward neural network (FFNN) model was presented and used for predicting the dyeing properties (L, a, b and K/S) of samples. The experimental results showed that the presented model achieves the regression values greater than 0.9 for all dyeing properties. Consequently, it was considered that the proposed FFNN was successfully modelled and could be efficiently utilised for dyeing characteristics of wool fabrics dyed with natural dye extracted from Hibiscus sabdariffa.     

A Review on Current Nanofiber Technologies: Electrospinning,Centrifugal Spinning,and Electro-Centrifugal Spinning

Nanofiber-based products are widely used in the fields of public health, air/water filtration, energy storage, etc. The demand for nonwoven products is rapidly increasing especially after COVID-19 pandemic. Electrospinning is the most popular technology to produce nanofiber-based products from various kinds of materials in bench and commercial scales. While centrifugal spinning and electro-centrifugal spinning are considered to be the other two well-known technologies to fabricate nanofibers. However, their developments are restricted mainly due to the unnormalized spinning devices and spinning principles. High solution concentration and high production efficiency are the two main strengths of centrifugal spinning, but beaded fibers can be formed easily due to air perturbation or device vibration. Electro-centrifugal spinning is formed by introducing a high voltage electrostatic field into the centrifugal spinning system, which suppresses the formation of beaded fibers and results in producing elegant nanofibers. It is believed that electrospinning can be replaced by electro-centrifugal spinning in some specific application areas. This article gives an overview on the existing devices and the crucial processing parameters of these nanofiber technologies, also constructive suggestions are proposed to facilitate the development of centrifugal and electro-centrifugal spinning.     

A Molecularly Engineered Zwitterionic Hydrogel with Strengthened Anti-Polyelectrolyte Effect: from High-Rate Solar Desalination to Efficient Electricity Generation

Polyzwitterionic hydrogel is an emerging material for solar-driven water evaporation in saline environment due to its special anti-polyelectrolyte effect, which is a promising approach to co-generation of freshwater and electricity. However, the molecular impact on anti-polyelectrolyte effect remains unclear, let alone to optimize the zwitterionic structure to promote water evaporation efficiency in high-salinity brine. Herein, a molecularly engineered zwitterionic hydrogel is developed and the incorporated phenyl-methylene-imidazole motif greatly enhances the salt binding ability and strengthens anti-polyelectrolyte effect, leading to boosted hydration, improved salt tolerance, ultra-low evaporation enthalpy (almost half of traditional zwitterionic gel), and durable anti-microbial ability in brine. Besides, gradient solar-thermal network is penetrated to optimize water transport channel and heat confinement. The gel exhibits excellent evaporation rate of 3.17 kg m⁻² h⁻¹ in seawater, which is 1.6 times of that in water and such high efficiency could be maintained during 8 h continuous desalination, demonstrating outstanding salt tolerance. The high flux of ion stream can generate considerable voltage (321.3 mV) simultaneously. This work will bring new insights to the understanding of anti-polyelectrolyte effect at molecular level and promote materials design for saline water evaporation.     

Functional Textiles with Smart Properties: Their Fabrications and Sustainable Applications

Benefiting from inherent lightweight, flexibility, and good adaptability to human body, functional textiles are attracting tremendous attention to cope with wearable issues in sustainable applications around human beings. In this feature article, a comprehensive and thoughtful review is proposed regarding research activities of functional textiles with smart properties. Specifically, a brief exposition of highlighting the significance and rising demands of novel textiles throughout the human society is begun. Next, a systematic review is provided about the fabrication of functional textiles from 1D spinning, 2D modification, and 3D construction, their diverse functionality as well as sustainable applications, showing a clear picture of evolved textiles to the readers. How to engineer the compositions, structures, and properties of functional textiles is elaborated to achieve different smart properties. All these tunable, upgraded, and versatile properties make the developed textiles well suited for extensive applications ranging from environmental monitoring or freshwater access to personal protection and wearable power supply. Finally, a simple summary and critical analysis is drawn, with emphasis on the insight into remaining challenges and future directions. With worldwide efforts, advance and breakthrough in textile functionalization expounded in this review will promote the revolution of smart textiles for intelligence era.     

Highly Breathable and Stretchable Strain Sensors with Insensitive Response to Pressure and Bending

Wearable tensile strain sensors have aroused substantial attention on account of their exciting applications in rebuilding tactile inputs of human and intelligent robots. Conventional such devices, however, face the dilemma of both sensitive response to pressure and bending stimulations, and poor breathability for wearing comfort. In this paper, a breathable, pressure and bending insensitive strain sensor is reported, which presents fascinating properties including high sensitivity and remarkable linearity (gauge factor of 49.5 in strain 0–100%, R² = 99.5%), wide sensing range (up to 200%), as well as superior permeability to moisture, air, and water vapor. On the other hand, it exhibits negligible response to wide-range pressure (0–100 kPa) and bending (0–75%) inputs. This work provides a new route for achieving wearing comfortable, high-performance, and anti-jamming strain sensors.     

Usability of state public health department websites for communication during a pandemic: A heuristic evaluation

Study aims were to investigate how usable COVID-19 dedicated state public health websites in the US were, and whether case counts in different geographical regions in the US were related to website usability. 16 state websites representing the 2 highest and the 2 lowest case count states in each region were selected. Five experts used a heuristic evaluation procedure to independently rate all 16 websites on a severity scale of 0–4. Usability criteria published by the US Department of Health and Human Services and criteria on risk communication and data dashboards were used. Analyses involved cross tabulation of usability criteria with case counts, comparison of usability scores using Mood's median tests, test of differences in average usability scores using ANOVA and post-hoc tests, and identification of correlations between case counts and usability scores. Results from the Mood's median test showed that the median usability scores for the states were significantly different from each other at the 5% level of significance (df = 15, chi-square = 38.40; p = 0.001). ANOVA showed statistically significant differences between the mean usability scores for the states at the 5% level of significance (F = 6.33, p < 0.05). Although not statistically significant, results from a correlation analysis between case count and usability scores showed a negative correlation (r = -0.209, p = 0.437) indicating that the higher the case count, the better the usability score. Overall, the websites fared well on usability, but many websites were used as an information and data repository. These websites must communicate infection risk better.Relevance to industryThe study applies to public health agency websites that communicate essential information during a pandemic.     

Functionalization of halloysite nanotubes with polyethyleneimine and various ionic liquid forms with antimicrobial activity

Halloysite nanotube (HNT), a natural clay, was modified with branched polyethyleneimine (PEI) to form PEI-HNT using epichlorohydrin (ECH) as coupling agent, then protonated with HCl to obtain H-PEI-HNTs providing [NH₃]⁺[Cl]⁻ functionality for potential antimicrobial properties. Upon PEI modification, zeta potential value of HNTs was increased to +37.3 mV from −34.5 mV and to +41.1 mV for H-PEI-HNTs. Only 1.87 wt % H-element in HNT was increased to 3.03 wt % upon PEI modification along with newly generated elements of N and C at 2.99 and 9.93 wt %, respectively. Moreover, ionic liquid (IL) forms of HNTs with [NH₃]⁺[N(CN)₂]⁻, [NH₃]⁺[PF₆]⁻ and [NH₃]⁺[BF₄]⁻ functionality were generated via anion exchange of H-PEI-HNTs with sodium dicyanamide (SDC), ammonium hexafluorophosphate (AHFP), and sodium tetrafluoroborate (STFB). The antimicrobial properties of the modified, protonated, and IL forms of HNTs were determined via macro dilution, diffusion and agar screening tests against Escherichia coli ATCC 8739, Pseudomonas aeruginosa ATCC 10145, Bacillus subtilis ATCC 6633, Staphylococcus aureus ATCC 6538 strains, and Candida albicans ATCC 10231 strains. It was found that H-PEI-HNTs possesses potent antimicrobial effect compared with the other forms of HNTs with 2–4 mg mL⁻¹ MIC and 8–16 mg mL⁻¹ MBC values via the macro dilution method. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48352.     

Effect of mechanochemical preparation of 2D g-C3N4 on electronic properties and efficiency of photocatalytic hydrogen evolution

A comparative study of morphology, spectral and photocatalytic properties of graphene-like C₃N₄ samples prepared by liquid-phase exfoliation of the bulk (l-C₃N₄) and mechanochemically delaminated g-C₃N₄ (m-C₃N₄) was performed for the first time. It was established that the particles of the mechanochemically prepared m-C₃N₄ are predominantly monolayer whereas the particles of l-C₃N₄ possess few-layer morphology. It was shown that m-C₃N₄ exhibits higher photocatalytic activity in the photocatalytic hydrogen evolution from aqueous solution of lactic acid under AM1.5G irradiation due to monolayer morphology, higher reduction potential, as well as more efficient separation and transfer of the photogenerated charges.