UV Blocking Research Articles

Microwave-assisted DES fabrication of lignin-containing cellulose nanofibrils and its derived composite conductive hydrogel

Abstract Currently, the rising environmental concerns caused by nonbiodegradable food packaging materials have promoted the research and development of biodegradable alternatives. Polyvinyl alcohol (PVA) was selected as the substrate, and zinc oxide nanoparticles (ZnONPs) and titanium dioxide nanoparticles (TiO2NPs) were blended and modified with PVA, respectively. Based on the electrostatic spinning technology to prepare fiber membranes with high strength and UV blocking properties for grapes preservation. The study indicated that the tensile strength of PVA fiber membranes increased by 243% and 209% when ZnONPs and TiO2NPs were added at 1%, respectively. Under UV radiation, the PVA/ZnO composite membranes exhibited superior UV absorption than the PVA/TiO2 composite membranes. After conducting TG tests, it was found that the addition of ZnONPs decreased the thermal stability of the fiber membranes, while TiO2NPs could improve the thermal stability. Both composite membranes could extend grapes' shelf life, but the PVA/ZnO composite membranes were more effective at maintaining freshness than the PVA/TiO2 composite membranes.

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

Abstract Graphene nanoribbon (GNR) is quasi‐one dimensional carbon based nanomaterial, distinct from graphene and less explored nanofiller in optical and optoelectronic applications. Herein flexible poly vinyl alcohol (PVA) nanocomposites of 0, 0.25, 0.5 and 0.75 wt % compositions of GNR were prepared by using solution intercalation technique and characterized by spectroscopic methods to assess their structural and optical characteristics. The characterization of PVA@GNR nanocomposites revealed Vander Waals binding of GNR to PVA chains and also considerable crystallographic changes in PVA matrix upon the incorporation of GNR. The optical investigations showed UV‐visible absorption in the wavelength range of 200–280 and 350–520 nm which enhanced on increase in GNR dopant concentration. The decrease in the optical band gap and Urbach energy was also observed for the nanocomposites with increase in dopant concentrations thereby suggesting the formation of localized states in the forbidden band region. The refractive index, absorption coefficient, extinction coefficient and optical conductivity of PVA nanocomposites showed excellent agreement with the band gap revelations and indicated UVC light blocking properties in the wavelength of 200–280 nm. Further, the GNR incorporated PVA nanocomposites exhibited improved thermal stability, wettability transitions (hydrophilic to near hydrophilic) and excellent luminescent down‐conversion properties with a high Stokes's shift (100 nm) compared to pristine PVA nanocomposites. The study concludes that the proposed PVA@GNR nanocomposites can ideally fit optical and photovoltaic device applications owing to their transparency coupled with UV blocking and luminescence down‐shifting attributes.

Ultrasonically functionalized chitosan-gallic acid films inactivate Staphylococcus aureus through envelope-disruption under UVA light exposure

Facile fabrication of arecanut palm sheath based robust hydrophobic cellulose nanopapers via self-assembly of ZnO nanoflakes and its shelf-life prediction for sustainable packaging applications

Construction of carboxymethyl chitosan/PVA/chitin nanowhiskers multicomponent film activated with Cotylelobium lanceolatum phenolics and in situ SeNP for enhanced packaging application

Smart contact lenses have recently gained traction due to their functionalization as noninvasive diagnostic and therapeutic wearables that can address several ocular diseases. Herein, multifunctional contact lenses exhibiting UV-transition and temperature-responsive capabilities were developed utilizing chromogenic materials that were integrated simultaneously into poly(2-hydroxyethyl methacrylate) (pHEMA) contact lenses. The functionalities of the contact lenses were optically evaluated in both their activated and non-activated states. Transition contact lenses offered excellent UV and blue light blocking capabilities (~45%) at their inactive states. When activated via UV exposure, the transparent lenses darkened instantaneously and absorbed portions of the visible light spectrum. The absorption intensity and transient discoloration of the transition lenses relied primarily on the utilized photochromic material. Likewise, the temperature-responsive contact lenses exhibited distinct colorimetric variations in response to temperature changes within the physiological range (33-38 °C). The maximum sensitivity of the thermochromic lens was 8% transmitted light per Celsius degree shift. Physiochemical and morphological analysis indicated the adequacy of the contact lenses. Hence, the multifunctional contact lenses can be deployed as smart wearables to manage ophthalmic deficiencies that are deterred by UV radiations and variations in ocular surface temperature.

For the sake of people's health and the safety of the environment, more efforts should be directed towards the fabrication of gas sensors that can operate effectively at room temperature (RT). In this context, increased attention has been paid to developing gas sensors based on rare-earth (RE)-doped transparent conducting oxides (TCO). In this report, lanthanum-doped zinc oxide (La-doped ZnO) films were fabricated by sol–gel and spin-coating techniques. XRD analysis revealed the hexagonal structure of the ZnO films, with preferred growth along the (002) direction. The crystallite size was decreased from 33.21 to 26.41 nm with increasing La content to 4.0 at.%. The UV–vis–NIR indicating that the films are highly transparent (˃ 80%), La-doping increased the UV blocking ability of the films and narrowed the optical band gap (Eg) from 3.275 to 3.125 eV. Additionally, La-doping has influenced the refractive index of the samples. Gas sensing measurements were performed at ambient temperature (30 °C) and a relative humidity (RH) of 30%, employing different flow rates of carbon dioxide (CO2) gas used synthetically with air. Among the evaluated sensors, the ZnO: 4.0 at.% La sensor exhibited the most significant gas response, with a value of 114.22%. This response was observed when the sensor was subjected to a flow rate of 200 SCCM of CO2 gas. Additionally, the sensor revealed a response time of 24.4 s and a recovery time of 44 s. The exceptional performance exhibited by the sensor makes it very appropriate for a wide range of industrial applications. Additionally, we assessed the effect of humidity, selectivity, reusability, repeatability, detection limit, and limit of quantification.

Composite films made of polyvinyl alcohol (PVA) filled with various coronene concentrations were fabricated via the solution casting method. Several characterization techniques were used to examine the prepared samples. The x-ray diffraction study shows decreasing semi-crystalline properties in PVA/coronene composites with increasing coronene levels, thereby improving charge carrier mobility and enhancing conductivity. The alterations in the chemical functional groups of the PVA/coronene composites were explored using Fourier-transform infrared spectroscopy (FTIR). The impact of coronene molecules on the optical characteristics of PVA was investigated in the spectral ranges of 190-2500 nm. PVA/coronene composite exhibits higher UV blocking in the 190-400 nm wavelength range, suitable for UV notch filters like laser blocking filters. By increasing the coronene filling ratio from 0 wt% to 3 wt%, both the indirect and direct optical band-gap of PVA films decreased from 5.19 eV and 5.77 eV to 3.85 eV and 5.18 eV, respectively. The single oscillator model (Wemple-DiDomenico) was used to explain the refractive index dispersion region. The extracted values of dispersion energy (Ed), oscillator energy (Eo), dielectric constant at infinite frequency (ε ∞), and lattice dielectric constant (ε L) of PVA/coronene composite samples increased from 0.78 eV, 2.41 eV, 1.32 and 1.41 to 13.44 eV, 12.22 eV 2.10 and 2.13, respectively. These changes in dispersion parameters are due to cross-linking between the PVA polymeric matrix and the coronene. As a result of these improvements, PVA/coronene films could be applied to flexible packaging applications and optoelectronic devices like solar cells or light-emitting diodes.

Atomic layer deposition of TiO2 nanolayer coated Vectran fabrics with enhanced UV-blocking performance and structural colors

Enhanced antibacterial properties of poly(butylene succinate-co-terephthalate)/Ag@MgO nanocomposite films for food packaging

Green synthesis of a broad-spectrum UV-blocking bitumen modifier: Investigation of anti-aging performance and mechanism in bitumen

Enhanced UV blocking, tensile and thermal properties of bendable TEMPO-oxidized bacterial cellulose powder-based films immersed in PVA/Uncaria gambir/ZnO solution

Zinc oxide enhanced the antibacterial efficacy of biodegradable PBAT/PBS nanocomposite films: Morphology and food packaging properties

Carrageenan-based multifunctional packaging films containing Zn-carbon dots/anthocyanin derived from Kohlrabi peel for monitoring quality and extending the shelf life of shrimps

Fabrication of biodegradable films with UV-blocking and high-strength properties from spent coffee grounds

Konjac glucomannan/carboxymethyl chitosan film embedding gliadin/casein nanoparticles for grape preservation

With the increasing awareness of ecological and environmental protection, the research on eco-friendly materials has experienced a considerable increase. The objective of our study was to explore a novel soy protein isolate (SPI) film functionalized with antioxidants extracted from Xanthoceras sorbifolia husk (XSHE) as bio-based active packaging films. The films were evaluated in light of their structure, physical machinery, and antioxidant performance using advanced characterization techniques. The FTIR and microscopy results revealed the hydrogen-bond interaction between the SPI and XSHE and their good compatibility, which contributed to the improvement in various properties of the composite films, such as tensile strength (TS), UV blocking, and the water barrier property. As the XSHE content increased to 5%, the TS of the films dramatically increased up to 7.37 MPa with 47.7% and the water vapor permeability decreased to 1.13 × 10-10 g m m-2 s-1 Pa-1 with 22.1%. Meanwhile, the introduction of XSHE caused further improvement in the antioxidant capacity of films, and the release of active agents from films was faster and higher in 10% ethanol than it was in a 50% ethanol food simulant. Overall, SPI-based films functionalized with XSHE demonstrated promising potential applications in food packaging.

How to effectively and greenly prepare multi-scale structural starch nanoparticles for strengthening gelatin film (ultrasound-Fenton system)