Good UV Research Articles

A novel modified polydopamine based on melanin-like materials for antibacterial, hydrophobic, and ultraviolet protective of textiles

The development of environmentally friendly multifunctional auxiliaries for textile modification is the focus of attention in textile industry in recent years. Polydopamine is an important biological macromolecule and widely used in biomedicine, nanomaterials, material surface modification and other fields. In this study, the novel multifunctional melanin-like nanoparticles (Nha-PDA NPs) were prepared and used for antibacterial, hydrophobic, and UV protective of textiles. Nha-PDA NPs were prepared with dopamine (DA) and n-hexylamine (Nha) by simple autoxidation copolymerization. Nha-PDA NPs were bound to the fabric surface through the PDA structure in Nha-PDA NPs that has been widely confirmed to have strong adhesion on the surface of many materials. The modified fabrics, Nha-PDA NPs@Cotton, had good hydrophobic, antibacterial and UV protective properties. The static water contact angles of the modified fabrics could reach 120°. The antibacterial rates of Nha-PDA NPs@Cotton against E. coli and S. aureus were above 85 %. The maximum UPF value of the modified cotton was 362, indicating that the ultraviolet protection performance was excellent. The fabric modified with multifunctional melanin-like nanoparticle provides a green way for the multifunctional modification of textiles.

Development and Analysis of Silver Nitroprusside Nanoparticle-Incorporated Sodium Alginate Films for Banana Browning Prevention

Banana (Musa acuminate) has been popular among consumers worldwide due to its rich nutrients and minerals. However, bananas are highly susceptible to the physical and biological factors that lead to postharvest loss during transportation and storage. In this work, novel sodium alginate (SA) films incorporated with silver nitroprusside nanoparticles (AgNNPs) were prepared to extend the shelf life of bananas through antibacterial and antioxidant coating. The results exhibited that AgNNPs were cubical and that their size was <500 nm, with metal composition being Ag and Fe. Additionally, the incorporation of AgNNPs in the SA film was seen in FE-SEM and zeta analysis, with an average size of about 365.6 nm. Furthermore, the functional and crystalline properties of AgNNPs were assessed through FTIR and XRD. Transmittance testing of the SA-AgNNPs films confirmed they have good UV barrier properties. SA-AgNNPs films exhibited excellent high antibacterial activity against foodborne pathogens including L. monocytogenes, S. enterica, and E. coli at the concentration of 500 µg/mL. Moreover, during the storage of bananas, SA-AgNNPs nanocomposite coatings act as a barrier to microbial contamination and slow down the ripening of bananas. As a result, compared with SA-coated and uncoated bananas, SA-AgNNPs-coated bananas exhibited the lowest weight loss and lowest total bacterial colonies, thus greatly extending their shelf life. Particularly when coated with SA-AgNNPs films, total bacterial colonies (TBC) in the banana peel and pulp were as low as 1.13 × 103 and 51 CUF/g on the ninth day of storage, respectively. Our work offers an efficient strategy to improve the quality of bananas during the postharvest period, with extensive applications in fruit preservation and food packing.

Single and hybrid effects of nano‐TiO2 and ‐ZnO particles on multifunctional properties of textiles

AbstractImpregnation of nano‐metal oxides can provide functional properties to textiles, like UV protection and self‐cleaning properties. These properties are quite important as they can provide protection against UV damage, help to reduce cleaning efforts, improve the ease of maintenance, and help to protect the water resources. The usage of nanoparticles improves multifunctional effects due to their high surface area. Therefore, in this study, nano‐sized TiO2 and ZnO were applied to cotton fabrics as single type or hybrids with different concentrations to reveal their effects on multifunctional properties (UV‐protection, self‐cleaning, wettability, photocatalytic activity). Also, the weight and air permeability of samples were determined to evaluate their usability. Scanning electron microscopy, x‐ray diffraction and Fourier transform infrared spectroscopy were also utilized to analyze the samples. According to the results, some samples exhibited good–very good UV protection. Up to 78.5% photocatalytic degradation of organic dye was achieved by nano‐TiO2 application. According to self‐cleaning test results, nano‐TiO2 applied samples showed yellowing after UV irradiation. Hybrid‐coated samples were more advantageous regarding self‐cleaning, especially against cherry juice stains. The staining and wettability results of the samples were in accordance. Weight and air permeability changes were acceptable to maintain the usage of the samples for clothing and other applications.

Preparation and application of high thermal conductivity phase change microcapsules with fluorescence characteristics based on a ZnWO4 shell.

Phase change microcapsules (NePCMs) with high latent heat values, thermal conductivity and stability were synthesized by coating stearic acid (SA) phase change materials (PCMs) with zinc tungstate (ZnWO4) as the shell material. The prepared ZnWO4 and microcapsule samples are characterized through various techniques, and their thermophysical properties under different core-shell ratios and emulsifiers are compared. The highest value that the phase transition enthalpy reaches is 83.63 J g-1 when the core-shell ratio is 1 : 1 and sodium dodecylbenzenesulfonate (SDBS) is adopted as the emulsifier. Based on SEM and TEM results, the regular spherical shape and the complete core-shell structure of the microcapsule can be found, and the particle size ranges between 100 and 300 nm. The thermal conductivity of SA increased by 141.18%-238.43% after using ZnWO4 as the shell material. Moreover, thermogravimetric and leak-proof performance tests demonstrated that microcapsule samples possess high thermal stability. There was no leakage from the six microcapsule samples after heating, proving their potential application in thermal energy storage (TES) under long-term high-temperature conditions. In addition, the cost of ZnWO4 prepared by this method can be reduced by about 40%. According to UV absorption and fluorescence spectrum evaluation, ZnWO4 and microcapsule samples exhibit good photoluminescence and UV absorption properties, indicating that the sample can be widely employed in fluorescent construction, coatings and textile industries at a lower cost.

Microstructure and Water Vapor Barrier Performance of Organic‐Bridged Polysilsesquioxane/Carbon Quantum Dots Composite Coatings

Developing siloxane‐based coatings with excellent water vapor barrier ability is of great importance due to their wide applications for various optical‐related fields. To improve the water vapor barrier ability of polysilsesquioxane coatings, this research proposes a strategy of introducing carbon quantum dots (CQDs) into organic‐bridged polysilsesquioxane coatings to enhance their water vapor barrier property. The CQDs are prepared by the pyrolysis of citric acid and then the composite coatings are prepared by thioether‐ester‐bridged silsesquioxane precursor in situ hydrolysis and condensation in the presence of CQDs. The experimental results show that the CQDs disperse well in the polysilsesquioxane matrix which is conducive to provide long diffusion pathway of water vapor molecules and also introduce individual “bubble pores” into the composite coatings. Thus‐obtained composite coatings not only show fivefold enhancement in water vapor barrier ability compared to the polysilsesquioxane coating without CQDs, but also perform good light transparence and good UV radiation‐resistant property, which would satisfy the requirements of optical‐related moisture‐resistant application fields.

Poly(methyl methacrylate)/hyperbranched polysiloxane hybrid prepared by gamma‐radiation polymerization: Thermal stability, optical transparence, and UV shielding

AbstractIt is challenging to endow poly(methyl methacrylate) (PMMA) with good dielectric properties and UV absorption capacity while simultaneously overcoming its poor heat resistance. Herein, we report for the first time a novel organic–inorganic hybrid (PMMA‐HBPSi) derived from methyl methacrylate (MMA) and hyperbranched polysiloxane (HBPSi) fabricated via γ‐radiation curing. The typical properties (thermal stability, optical characteristics, and dielectric properties) of the hybrids were systematically investigated and discussed. The results demonstrated that the incorporation of HBPSi into the PMMA resin not only increased the thermal resistance, dimensional stability, and dielectric properties but also remarkably reduced the UV transmittance. Specifically, in comparison with pure PMMA, the initial degradation temperature (Tdi) of PMMA‐HBPSi increased by 31°C, with no phase transition occurred in a temperature range of 60–230°C, thus illustrating a significant improvement in the glass‐transition temperature. Moreover, the thermal expansion coefficient decreased by 86.9% at temperatures exceeding 118°C. The UV transmittance of PMMA was also found to decrease by 80% at 295 nm after the introduction of HBPSi. These attractive features of PMMA‐HBPSi demonstrate that the new approach proposed here is suitable for developing high‐performance organic glasses for optical, aviation, and electronic applications.

Polymer composites used to manufacturing Naturacustic® acoustic screens

In this study the functional properties and the production process of PVC matrix composites used in the technology of a new type of pro-environmental noise barriers for use in road construction, sound shielding of urban settlements, bridges, railroad tracks were described. PVC matrix composites were obtained by stirring extrusion using a single-screw extruder. The samples for mechanical tests, flame resistance and aging tests were obtained in the form of barrels and paddles using an injection molding machine. Based on the test results, it was found that the developed PVC composites have the following properties: Charpy impact strength greater than 12 kJ/m2, hardness according to Rockwell exceeding 78 N/mm2, oxygen index equal to 50% and good UV resistance at 3000 h. An important advantage of these composites is the agro-food waste content of 30 wt%, which makes the materials environmentally friendly.

PBSeT/lignin: A complete bio-based biodegradable plastic with excellent mechanical and anti-UV properties

Herein, a complete bio-based biodegradable plastic with excellent properties was fabricated based on Poly (butylene sebacate-co-terephthalate) (PBSeT) and lignin. Moreover, a biodegradable epoxidized soybean oil (ESO) was used as the compatibilizer through the ring-opening reaction between ESO and the hydroxyl groups of lignin and PBSeT during the reactive extrusion. The results show that the plastics had excellent properties, the tensile strength and the elongation at break could reach 13.04 MPa and 328.33 %, respectively. Moreover, the addition of lignin endowed PBSeT with good UV resistance. Conclusively, this strategy expands the application of lignin in the degradable polyester matrix and broadens the application of lignin accordingly.

Amorphous transparent conducting oxide for van-der Waals semiconductor bifacial transparent photovoltaics

Building integrated photovoltaic systems have necessitated the development of transparent photovoltaics (TPV). Transparent conducting oxides (TCO) play a vital role in charge carrier transport in TPVs. Their high transparency, electrical conductivity, and tunable work function make them imperative for TPV applications. Here in this work, we develop a room-temperature grown amorphous-InZnO (a-IZO) thin film for the bottom electrode for TPV. The a-IZO film has demonstrated a high average visible transmittance of 84 % over commercial F:SnO2 (FTO) substrate. A TPV with wide band gap oxide (n-Ga2O3) and a very thin layer of van der Waals material (p-SnS) was fabricated over the a-IZO thin film and commercial FTO substrate for better comparison. A significant enhancement in the current density, open-circuit voltage, and fill factor was recorded. The device with a-IZO electrode showed a bifacial power production feature with a power conversion efficiency of 3.9 % in contrast to FTO electrode-based TPV with 1.5 %. The a-IZO-based TPV also showed a good UV–vis photodetection ability with the highest responsivity of 93 mA/W and the fastest response time of 400 μs. This work suggests that enhanced photovoltaic and photodetection performance is possible using an optimum electrode design.

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A high‐performance and sustainable structural functional material has been developed from natural pinewood, enabled by the unique ionic bond. The obtained material shows good water resistance, thermal conductivity, thermal stability, UV resistance, corrosion resistance and antibacterial properties. This material has promising applications in waterproof enclosure structure, underfloor heating, UV resistant protective cover, and anti‐corrosion materials, etc. image

Engineering eco-friendly and biodegradable biomass-based multifunctional antibacterial packaging films for sustainable food preservation

The study presents a new class of eco-friendly and biodegradable biomass-based multifunctional antibacterial packaging films (G-OCSI) based on oxidized corn starch-based nonionic biopolymer (OCSI) and gelatin (Gel), and investigates the effects of different OCSI contents on the properties of G-OCSI. The results demonstrated that G-OCSI 0.25 had good water vapor barrier properties, antioxidant activity (DPPH RSA: 85.84 %), UV resistance (UV blocking > 99.9 %), water resistance (WCA: 122.30°), and tensile properties. Based on the disk diffusion experiment, G-OCSI exhibited significant bactericidal and antibacterial effects against S. aureus and E. coli. Moreover, G-OCSI had good biodegradability in natural environments, and could obviously accelerate the crops growth. Finally, a banana preservation experiment confirmed that G-OCSI could significantly extend the shelf life of bananas at room temperature at least 3 days. The biodegradable packaging films not only realizes the sustainable utilization of biomass resources but also has the potential to replace traditional petroleum-based plastics.

Development of biodegradable films reinforced with silver functionalized cow milk carbon dots for active food packaging applications

Synthetic food packaging films exhibit poor biodegradability and their use has resulted in significant environmental issues. The objective of this work was to develop organic, biopolymer-based antibacterial packaging films as an alternative to synthetic packaging films. In this study, agar was chosen as a biopolymer matrix, carbon dots (CDs) derived from cow milk served as an antibacterial source and Ag nanoparticles were added to enhance the antibacterial activity. The prepared films were characterized by SEM, TEM, UTM, XRD, TGA-DTA, FT-IR, and water contact angle measurements. The prepared films showed good antibacterial activity against E.coli and S. aureus and a tensile strength value of about 41.85 MPa. In addition to these, the prepared films showed good biodegradable properties of about 86 % degradation in 60 days and good UV barrier properties. Finally, the films were tested for real-time application on sliced tomatoes, which also showed good results even after 4 days at room temperature.

Combination of bio-based tannic acid, sophora flower extract and metal salts: A facile route towards improving durable flame retardancy and UV resistance of silk fabrics

Environmental engineering placed green demands on the functional modification of textiles. Here, the combination of bio-based tannic acid, sophora flower extract and metal salts was used to manufacture silk fabrics with flame retardancy and UV resistance via a facile impregnation strategy. With different metal salts treated, the modified silk fabrics named silk/TA/SFE-TE, silk/TA/SFE-Fe and silk/TA/SFE-Cu achieved self-extinguishing in the vertical burning test, with limiting oxygen index values of 31.7 ± 0.4 %, 30.2 ± 0.2 % and 30.9 ± 0.3 %, respectively. In the cone calorimetry test, the peak heat release rate values of the three silk fabrics modified with metal salts were all significantly suppressed, and the total smoke production values of silk/TA/SFE-TE and silk/TA/SFE-Fe were reduced from the original 0.178 m2 to 0.126 m2 and 0.138 m2, respectively. Furthermore, silk/TA/SFE-TE, silk/TA/SFE-Fe and silk/TA/SFE-Cu displayed high ultraviolet protection factor values and thus had good UV resistance, owing to the presence of tannic acid and sophora flower extract. Most importantly, the flame retardancy and UV resistance of the three silk fabrics modified with metal salts were still superior to those of the original silk fabrics after 30 washing cycles. In short, this facile route for the preparation of functionalized silk fabrics provides a novel idea for the development of advanced textiles.

Preparation of a UV anti-aging and superhydrophobic self-cleaning coating by loading nano-rutile on sericite and being modified with HDTMS

To enhance the anti-aging property of a superhydrophobic self-cleaning coating, rutile nano-TiO2 was loaded onto the surface of sericite via wet grinding method to prepare sericite-rutile composite particles. Then, the composite was modified with hexadecyltrimethoxysilane (HDTMS) and sprayed onto the substrates surfaces to prepare sericite-rutile/HDTMS composite coatings with both UV shielding and superhydrophobic self-cleaning properties. The structure, properties, and mechanism of the coating were studied. The research showed that the micro-nanoscale hierarchical structure has been constructed by compositing sericite and rutile, which were the structure foundation of superhydrophobic coatings. The sericite-rutile composite was modified with HDTMS and sprayed onto the substrates forming a superhydrophobic self-cleaning coating. Water contact angles (WCAs) and slide angles (SAs) of the coating were 155.3° and 1.3°, respectively. The sericite-rutile/HDTMS coating exhibited good UV shielding and anti-aging properties. Its UV shielding rate was 93.53%, which was equivalent to that of pure rutile (94.27%). After UV irradiation for 80 h, the surface maintained superhydrophobicity, and the chromaticity of the coating surface did not change. The superhydrophobicity and low adhesion to water of the sericite-rutile/HDTMS coating are due to the micro-nano hierarchical structure of the sericite-rutile composite and the low surface energy of HDTMS. The UV shielding effect of the coating is mainly due to the strong absorption of UV light by the sericite-rutile composite. This work provides a simple and environmentally friendly method for constructing a coating with UV shielding and superhydrophobic self-cleaning properties.

Reducing fire hazards and enhancing the thermal stability, acoustical, and UV protection of polyvinyl alcohol using bio-based flame retardant

Polyvinyl alcohol (PVA) is a highly flammable material, and enhancing its flame retardancy to pass the glow wire test is a great challenge. In this work, the melamine salt of tannic phosphate (MTP) was synthesized, characterized, and combined with PVA at 8, 10, 13, and 15 wt%. The thermogravimetric analysis (TGA) results indicated that MTP enhanced the char formation of PVA at 750°C. Flammability tests showed that low concentrations of MTP can enhance the flame retardancy of PVA. The limiting oxygen index (LOI) of PVA increased from 18.8% to 39.9% in the PVA/15%MTP composite. The vertical flame spread test (UL94V) showed that PVA/13%MTP, and PVA/15%MTP composites achieved V0 rating. Glow wire test data indicated that PVA/10%MTP, PVA/13%MTP, and PVA/15%MTP composites had a glow wire flammability index (GWFI) of 960°C/2 mm. Moreover, all the composites passed the needle flame test when the flame application time was 120 s. PVA/15%MTP composite showed very good UV protection and an increase in sound absorption coefficient magnitude compared with pure PVA. The new results can increase the application of PVA in different industries.

Centrosomal protein of 192 kDa (Cep192) fragment possesses bactericidal and parasiticidal activities in Larimichthys crocea

A novel AMP Lc1773, derived from centrosomal protein of 192 kDa (Cep192), was isolated from Larimichthys crocea using a Bacillus subtilis system. After cDNA libraries construction, repeating selection of B. subtilis system, extraction of extracellular protein, and expression of recombinant protein, we found that B. subtilis 1773, extracellular protein, and rLc1773 had a strong potential to kill Vibrio. parahaemolyticus and V. vulnificus. Further analysis of the antibacterial mechanism revealed that rLc1773 not only disrupted the integrity of bacterial membrane (as confirmed by SEM, TEM, and confocal microscopy observation, and flow cytometry assays), resulting in bacterial cell membrane pore conformation, bacterial rupture, and leakage of cellular contents, but also targeted to block protein synthesis rather than damage nucleic acids (as confirmed by SDS-PAGE, enzyme expression, and gel retardation assays). In addition, rLc1773 had the ability to kill parasite Scuticociliatida in a high rate and low concentration. Critically, the antibacterial activity of rLc1773 had good thermal stability and UV radiation tolerance, but it was affected by pH 9–11 and diverse enzyme to some extent. Lc1773 had neither hemolysis on fish, shrimp, and rabbit erythrocytes，nor significant cytotoxicity. To our knowledge, Cep192 fragment was first demonstrated to possess bactericidal and parasiticidal activities.

Optical structural and thermal studies of TiO2@ZnO core-shell incorporated methylene blue dye doped PVA polymer nanocomposites

This manuscript makes an effort to achieve the synthesis of titanium dioxide (TiO2)@ Zinc oxide (ZnO)core@shell also development and study of methylene blue (MB)/TiO2@ZnO/poly(vinyl chloride) (PVA)polymer nanocomposites (PNCs) for optical applications. The PNCs were constructed using easy solution-casting method, advertised good UV–vis and fluorescence properties. The fluorescence emission spectra of MB/TiO2@ZnO/PVA PNCs show the broad peak around 685 nm for both 614 nm and 665 nm excitation wavelengths for all samples and it is observed that the intensity falls off as increase in the dye amount. The x-ray diffraction (XRD) spectra of well-developed PNCs exhibit amorphous nature and the other outcomes obtained by various techniques correlating with each other. Hence, the prepared PNCs can be used for fabricating red light emitting diode (LED) to improve the eye sight of human being.

Sustainable ultra‐strong thermally conductive wood‐based antibacterial structural materials with anti‐corrosion and ultraviolet shielding

AbstractIn light of the uprising global development on sustainability, an innovative and environmental friendly wood‐based material derived from natural pinewood has been developed as a high‐performance alternative to petrochemical‐based materials. The wood‐based functional material, named as BC‐CaCl2, is synthesized through the coordination of carboxyl groups (−COOH) present in pinewood with calcium ions (Ca2+), which facilitates the formation of a high‐density cross‐linking structure through the combined action of intermolecular hydrogen bonds. The as‐prepared BC‐CaCl2 exhibits excellent tensile strength (470.5 MPa) and flexural strength (539.5 MPa), establishing a robust structural basis for the materials. Meanwhile, BC‐CaCl2 shows good water resistance, thermal conductivity, thermal stability, UV resistance, corrosion resistance, and antibacterial properties. BC‐CaCl2 represents a viable alternative to petrochemical‐based materials. Its potential application areas include waterproof enclosure structure of buildings, indoor underfloor heating, outdoor UV resistant protective cover, and anti‐corrosion materials for installation engineering, and so forth.image

Sustainable green composite of yam and agricultural waste corn stalk fiber with good mechanical, thermal, optical, aging performance and excellent biodegradability

Sustainable green composites with safe biodegradability produced using environmentally benign materials are required as modern-day alternatives for harmful synthetic materials. Agricultural waste such as corn stalks and underutilized natural polymer sources such as yam are significant potential candidates in this regard. In our work, a green composite of yam and alkali-treated corn stalk fiber was prepared through a simple solution casting and oven-drying method. The successfully prepared green composites displayed good mechanical and thermal properties as the corn stalk fibers effectively reinforced the yam bioplastic matrix. Spectral studies such as FTIR, SEM, and p-XRD confirmed the probable structural changes and formation of the composites. Prepared green composites possessed high resistance and good thermal (−2 °C and 70 °C), UV (254 nm for 180 hours), and chemical aging properties along with low moisture absorption behavior. Further, the green composites showed excellent biodegradable nature under normal environmental conditions. Thus, potentially capable green composite for applications in packaging, biomedical, automobile, and construction sectors was reported here.

Thermodynamic, thermoelectric and optoelectronic performances of Co2MB (M = Nb, Ta) full-heusler compounds for solar cell and UV absorber applications

An investigation for estimating the thermodynamic, thermoelectric and optoelectronic performances of Co2MB (M = Nb, Ta) full-Heusler compounds is accomplished via density functional theory within full-potential linearized augmented plane wave (FP-LAPW) method. The generalized gradient approximation (GGA), GGA + U (Hubbard correction), Tran-Blaha modified Becke-Johnson potentials (TB-mBJ) and spin-orbit coupling (SOC) are utilized to handle the exchange and correlation potential. The electronic band structure of Co2NbB and Co2TaB confers half-metallic nature over reasonable band gaps; 0.71 and 1.11 eV, respectively within mBJ potential. The materials are manifested with the integer values of spin magnetic moment. Further, various thermodynamic parameters under the effect of temperature and pressure have been assessed. Interestingly, Co2NbB and Co2TaB exhibit fantastic thermoelectric performances concerning high figure of merit at 1200 K. Furthermore, the computed materials are optically active and display absorption spectra in visible and more significantly in UV region of incident light. Therefore, materials can be used as good UV absorbers.