Excellent UV-blocking Research Articles

Growth of ZnO nanorods on cotton fabrics via microwave hydrothermal method: effect of size and shape of nanorods on superhydrophobic and UV-blocking properties

In this present research, a novel microwave hydrothermal method was applied to cotton fabrics to develop a superhydrophobic surface by rapid synthesis of aligned ZnO nanorods on the surface of the cotton fabric. A two-step approach was used to grow the ZnO nanorods. Firstly, the cotton fabric was coated by a seed layer of ZnO nanocrystals, synthesized using the microwave-assisted sol gel method. Secondly, the ZnO nanorods were grown rapidly on the seeded cotton fabrics using the microwave hydrothermal method. Moreover, a layer of non-fluorinated silane was applied on the as-grown nanorods to fabricate a superhydrophobic surface. Non-fluorinated silane was selected as it is less harmful to the skin than fluorinated silanes. The effect of the zinc nitrate hexahydrate (Zn(NO3)2·6H2O) concentration, reaction time and microwave power on the growth of ZnO nanorods was investigated in detail using scanning electron microscopy. The surface topography and roughness of the nanorods grown on the fabrics were studied using atomic force microscopy. EDS analysis and X-ray diffraction techniques were used to study the structural properties of the ZnO nanorods. The ultraviolet protection properties were investigated by a UV–Vis-NIR spectrophotometer. The ZnO nanorods grown on the cotton fabrics exhibited excellent UV blocking properties. A maximum UPF value of 114 was observed for the ZnO nanorods grown on the cotton fabric with 100 mM of zinc nitrate hexahydrate (Zn(NO3)2·6H2O). The superhydrophobic properties were examined based on contact angle and roll-off angle measurements, where a maximum water contact angle of 170.2° and a minimum roll-off angle of 1° were found for 25 mM of zinc nitrate hexahydrate. The ZnO-OTMS coated fabrics were evaluated for superhydrophobic durability against mechanical abrasion, laundering, chemical and UV action. Moreover, the ZnO-OTMS coated fabrics showed excellent potential for separation of floating and underwater oil layers or an oil–water mixture.

Consolidation of cellulose nanofibrils with lignosulphonate bio-waste into excellent flame retardant and UV blocking membranes

The use of biomass to produce value-adding materials is a core objective of the circular economy, which has attracted great research interest in recent decades. In this context, we present here a simple dispersion-casting process for consolidation of cellulose nanofibrils (CNF), lignosulphonate (LS)-rich bio-waste and CaCl2 in composite membranes. The addition of CaCl2 to CNF and LS dispersions reduces the ζ potential, due to an electrostatic screening, which promotes the aggregation of CNF, increases its moisture content and promotes LS deposition on CNFs already in the dispersion phase. Addition of both the LS and CaCl2 to CNF dispersion has an adverse effect on the mechanical properties of the final membranes. The effectiveness of the new composite membranes has been described in terms of their passive (charring) flame retardancy and 100 % UVA/UVB shielding capacity, both identified for membranes with the highest LS content, as well as high electronic resistance.

Very Strong, Super-Tough, Antibacterial, and Biodegradable Polymeric Materials with Excellent UV-Blocking Performance.

In this work, inspired by the dynamic sacrificial hydrogen bonds in biological materials, a very strong, super-tough, antibacterial, and cost-effective biodegradable poly(vinyl alcohol) (PVA) nanocomposite material was developed by incorporating the nanoscale antibacterial agent TA@LS-Ag. TA@LS-Ag was prepared from the green biomass tannic acid (TA) and sodium lignosulfonate (LS), and was facilely incorporated into the PVA matrix with a homogeneously interspersed nanoparticle size of about 20 nm. The PVA nanocomposite film with 2 wt % addition of TA@LS-Ag achieved the highest specific toughness of 262 J g-1 among the PVA-based films to date, which is far higher than that of natural spider silk (150-190 J g-1 ), as well as a very high tensile strength of 131.6 MPa. The excellent tensile strength and superior toughness were attributed to synergy of the nanophase separation structure and the intense hydrogen-bonding interactions between the nanoparticles and PVA matrix. The PVA/TA@LS-Ag nanocomposite films exhibited good antibacterial properties, despite the extremely low silver content (0.032-0.32 wt ‰). TA@LS-Ag also endowed the PVA films with excellent antioxidant and UV-shielding performance. As the biomass-derived LS and TA and the PVA matrix are all biodegradable, this work offers a facile strategy for preparing high-performance antibacterial and biodegradable polymeric materials.

Strong biodegradable cellulose materials with improved crystallinity via hydrogen bonding tailoring strategy for UV blocking and antioxidant activity

It has been a huge challenge to obtain simultaneously excellent mechanical strength and desirable multifunctionality from the cellulose nanocrystals (CNC) based food packing materials. In this work, we demonstrated a hydrogen bonding tailoring strategy that can produce CNC/lignin films with UV blocking and antioxidant activity, while bypassing the loss of mechanical strength. Using a hyperbranched polyester, lignin was first functionalized to increase the amount of hydroxyl groups, thereby increasing the intermolecular interactions. By assembling the polyester modified lignin (H-lignin) into CNC matrix, the hydrogen bonding crosslinks between the H-lignin and CNC chains were successfully promoted, resulting in the CNC composites with the significantly improved mechanical strength, UV blocking and antioxidant activity. The phenolic structure and the hydrogen donation of H-lignin also endowed the resulting CNC composites with excellent UV blocking and antioxidant activity. The experimental results indicated that the H-lignin could bring about 34% and 63% increase in tensile strength and Young's modulus, respectively, higher than the reported ones. The CNC-based composites showed better thermal stability and improved crystallinity property. The H-lignin provides a new insight into the multifunctional exploration of CNC-based composite. This work opens a new avenue for the next generation's biodegradable food packing materials from cellulose-sourced composites.

Superhydrophobic and anti-ultraviolet polymer nanofiber composite with excellent stretchability and durability for efficient oil/water separation

Superhydrophobic nanofibrous membranes have attracted tremendous attention to deal with some environmental problems like oil leakage and wastewater treatment; however, their poor durability, recyclability and stability limit their broad applications in the complex and harsh water treatment. Here, we prepared a superhydrophobic, anti-ultraviolet, durable and stretchable nanofiber composite membrane. TiO2 nanoparticles were anchored onto the thermal plastic polyurethane (PU) nanofiber surface by ultrasonication, followed by polydimethylsiloxane (PDMS) modification. PDMS could decrease the nanoparticle surface energy and hence improve the hydrophobicity of the nanofibrous membrane. More importantly, it was served as a “glue”, significantly enhancing the interfacial adhesion between the TiO2 nanoparticles and PU nanofibers and thus the mechanical properties. The obtained composite membrane displayed excellent corrosion resistance and UV blocking performance, which could be maintained after cyclic mechanical tests. The superhydrophobic/superoleophilic nanofiber composite could separate oil with not only water but also salt, acid and alkaline solution. In addition, the nanofiber membrane could be repeatedly used with the stable separation flux and efficiency, displaying great durability and recyclability.

The synthesis of a DHAD/ZnAlTi-LDH composite with advanced UV blocking and antibacterial activity for skin protection

Skin wounds are particularly vulnerable and susceptible to bacterial infection. Unfortunately, the abuse of antibiotics has resulted in the emergence of a number of multidrug-resistant bacteria in the past few decades. Moreover, secondary damage of the fragile new tissue around the wound caused by high-energy ultraviolet (UV) radiation has been rarely noticed. To address these problems, herein, we present an alternative strategy to overcome drug-resistant bacteria and UV damage by taking advantage of dehydroabietic acid derivatives (DHADs) and layered double hydroxides (LDHs). DHAD, synthesized from dehydroabietic acid (DHA) through a series of reactions, was assembled with ZnAlTi-LDH to obtain a DHAD/ZnAlTi-LDH composite. The results showed that DHAD/ZnAlTi-LDH has a prominent reactive oxygen species (ROS) production capacity, and both Gram-negative and positive bacteria can be killed under visible light irradiation. At the same time, it can effectively shield the skin from UV rays. In vitro and vivo experiments confirmed that the composite has great promise for bactericidal applications, UV blocking and wound healing.

A renewable dynamic covalent network based on itaconic anhydride crosslinked polyglycerol: Adaptability, UV blocking and fluorescence

An adaptive dynamic covalent network with UV blocking and fluorescence is prepared by crosslinking hyperbranched polyglycerol (HPG) with itaconic anhydride (IA) via esterification. The abundant hydroxyl groups and ester linkages in the resulting polymer (HPG/IA) afford the dynamic transesterification at elevated temperatures and enable adaptive behaviors such as stress relaxation and reparability. Because the double bonds of IA are purposely reserved in the crosslinked network, the HPG/IA exhibits excellent UV blocking due to the strong UV absorption of the double bonds. HPG/IA also exhibits strong glass adherence. With a OH/anhydride ratio of 4/1, HPG/IA displays an adhesion shear strength to glass of ~30 kPa, which is explained by the flexible structure that ensures a good contact of the polymer film with glass and the high dielectric constant that favors accumulation of electrostatic charges. Interestingly, HPG/IA exhibits strong fluorescence (FL) under UV light, and the FL of HPG/IA exhibits strong selective quenching with respect to Fe3+. These unique properties make HPG/IA a promising functional material for UV blocking glass film and fluorescent Fe3+ sensor.

Development of new composite fibers with excellent UV radiation protection

Abstract This work reports the design and functionalization of new composite-based polyethylene terephthalate (PET) fibers with high anti UV radiation. Polyethylene terephthalate fibrous nonwovens were coated by materials oxides (MOx) like titanium dioxide (TiO2), zinc oxide (ZnO) and silicon dioxide (SiO2). Chitosan (CT) and polyvinylidene fluoride (PVDF) polymers were used to ensure the good surface compatibility of the resulting composite PET-PVDF-MOx-CT. These composites were fully characterized and the chemical coatings, surface modification, physical and thermal properties were investigated. Incorporation of materials oxides resulted in the formation of strong cross-linked chitosan network. The developed modification on PET nonwovens allows to highly reducing the UV radiation with an excellent blocking rate and a good UV protection factor (80.5–113.4). An outline mechanism is proposed for the UV protection. This was explained by the surface compatibly and the interfacial bonding occurred in the matrix. Regarding to the above results, the current work developed a facile process for the production of advanced materials based nonwovens with excellent UV blocking.

High performance PVA/lignin nanocomposite films with excellent water vapor barrier and UV-shielding properties

High performance poly(vinyl alcohol) (PVA)/lignin nanomicelle (LNM) nanocomposite films with good vapor barrier and advanced UV-shielding properties were fabricated in this study. LNM was homogeneously distributed in the PVA matrix and strong robust hydrogen bonds were successfully constructed between LNM and PVA matrix. With only 5 wt% loading of LNM into the PVA/LNM nanocomposite, the water vapor transmission rate (WVTR) was declined by about 189% compared with pure PVA. Moreover, after introducing lignin, the PVA nanocomposite films showed improved tensile strength and toughness, excellent UV-blocking and good thermal stability. As both lignin and PVA are biodegradable, this study shows a meaningful design approach for biodegradable functional nanocomposite films using cheap and easily available biomass and biodegradable raw materials.

In situ assembly of halloysite nanotubes@cerium oxide nanohybrid for highly UV-shielding and superhydrophobic coating

CeO2 nanoparticles were successfully anchored on the surface of halloysite nanotubes (HNTs) by in situ assembly approach to fabricate a novel nanohybrid (HNTs@CeO2). The structure and composition of HNTs@CeO2 were systematically investigated by SEM, TEM, XRD, XPS and TGA. It suggested that the severe aggregation of CeO2 nanoparticles got efficiently suppressed with the aid of HNTs nanocarrier. And the unique hybrid architecture of HNTs@CeO2 endows the silicone coating with excellent UV-blocking effect. Specially, the polydimethylsiloxane (PDMS)/HNTs@CeO2 coating with a mass ratio of 15:1 (HNTs@CeO2: PDMS) could shield 93% ultraviolet B (UVB) and 84% ultraviolet A (UVA). Furthermore, the PDMS/HNTs@CeO2 coating also exhibited synergic feature of outstanding superhydrophobicity and excellent self-cleaning function. In summary, this work has proposed a practical method to resolve the severe aggregation of CeO2 nanoparticles and fabricated a highly UV-shielding and superhydrophobic silicone coating, which may offer a valuable inspiration for the fabrications of nanohybrid and multifunctional coating.

Water-resistant, transparent, uvioresistant cellulose nanofiber (CNF)–aramid nanofiber (ANF) hybrid nanopaper

A promising strategy to synergistically improve the water resistance, wet strength and UV-blocking property of cellulose nanofiber (CNF) nanopaper via layer-by-layer (LBL) assembly of aramid nanofiber (ANF) film was proposed. The water resistance, optical properties and mechanical performances (in dry and wet states) of the resultant CNF@ANF hybrid nanopapers were investigated. The results show that CNF@ANF nanocomposites display excellent water resistance, wet strength and UV-blocking properties. Especially, the wet strength of CNF@ANF10 paper reached 101 MPa after soaked in water for 24 h, which was 86 times higher than pure CNF nanopaper, representing one of the strongest CNF-based hybrid nanopapers in fully wet conditions, which will be favorable for the potential advanced applications.

Fabrication of High Nano-ZnO Assembled Cotton Fabric with UV Blocking Property

In order to fabricate a novel ZnO/cotton composite, a high proportion of ZnO nanoparticles were assembled in cotton fibers, and the as-obtained cotton fabric can possess better UV blocking property compared with common ZnO/cotton composite. Firstly, the cotton fibers were pre-treated by hydrogen peroxide solution(H2O2) and sodium hydroxide(NaOH), urea(CON2H4). Secondly, the fabric was fabricated via in situ deposition. The effects of concentration of treatment liquid, ammonia-smoking time and curing temperature on the tensile property of the fabric, UV blocking property and water-washing durability test of as-obtained cotton fabrics were investigated. Thirdly, the as-obtained cotton sample was characterized by X-ray diffraction(XRD) and field emission scanning electron microscopy(FESEM). It was shown that ZnO nanoparticles were assembled between cotton fibers, the surface and inside of the lumen and the mesopores of cotton fibers, while the content of nano-ZnO assembled in fabric can reach 15.63wt%. It is proved that the finished fabric can obtain a very excellent UV blocking property, under the condition of zinc ion in concentration of 15wt%, ammonia-smoking time for 10 min, curing temperature at 150 °C for 2 min.

Citrate-based fluorophores in polymeric matrix by easy and green in situ synthesis for full-band UV shielding and emissive transparent display

Developing easy and green strategy to prepare functional materials with outstanding properties based on naturally abundant and environmentally friendly raw materials is highly desirable for sustainable development. Herein, an easy and green strategy was reported to in situ synthesize and disperse citrate-based fluorophores (CFs) in polyvinyl alcohol (PVA) matrix. By a simple heating treatment of the mixture aqueous solution of citric acid/cysteine/PVA, CF–PVA blends were obtained in the form of homogeneous transparent films or coatings. Due to the effective UV absorption of CFs, CF–PVA film and coating exhibited full-band blocking of UV irradiation while still allowing high transmission of visible light. Protection by CF–PVA film and coating effectively reduced UV-induced rhodamine B degradation and cell death. Furthermore, the down-conversion property of CF–PVA coating enables conversion of invisible UV irradiation into visible blue light emission, and we further demonstrated the application of CF–PVA coating for fabricating emissive transparent display. Given the abundant and environmentally friendly raw materials, easy and green preparation, excellent UV-blocking, and converting properties, we believe that the CF–PVA blends are promising for applications in UV shielding, transparent display, and energy harvesting.

Investigating the Synthesis and Characterization of a Novel "Green" H₂O₂-Assisted, Water-Soluble Chitosan/Polyvinyl Alcohol Nanofiber for Environmental End Uses.

The present work highlights the formation of a novel green nanofiber based on H2O2-assisted water-soluble chitosan/polyvinyl alcohol (WSCHT/PVA) by using water as an ecofriendly solvent and genipin used as a nontoxic cross-linker. The 20/80 blend ratio was found to have the most optimum uniform fiber morphology. WSCHT retained the same structure as WISCHT. The prepared nanofibers were characterized by Scanning electron microscopy (SEM), Fourier transform spectroscopy (FTIR), Thermo gravimetric analysis (TGA), Differential scanning calorimeter (DSC), X-ray diffraction (XRD), Water Contact Angle (WCA) and Ultraviolet-visible spectroscopy (UV-vis). During electrospinning, the crystalline microstructure of the WSCHT/PVA underwent better solidification and after cross-linking there was an increase in the melting temperature of the fiber. Swelling ratio studies revealed noticeable increase in hydrophilicity with increase of WSCHT, which was further demonstrated by the decrease of contact angle from 64.74° to 14.68°. WSCHT/PVA nanofiber mats exhibit excellent UV blocking protection with less than 5% transmittance value and also showed improved in vitro drug release properties with stable release for longer duration (cross-linked fibers) and burst release for shorter duration (uncross linked) fibers. Finally our experimental data demonstrates excellent adsorption ability of Colour Index (C.I.) reactive black 5 (RB5) due to protonated amino groups.

Role of solid lipid nanoparticles as photoprotective agents in cosmetics.

Novel drug delivery systems have gained popularity since last two decades because of its advantages over conventional dosage forms. Effect of UV radiation on skin can cause either acute or chronic damage to our skin. Solid lipid nanoparticles (SLNs) were developed as novel carrier over the conventional carrier systems like liposomes and emulsions. The SLNs were selected as a carrier for the formulation because of its ability to protect the labile drug particles, the ability to make the drug release in a controlled manner, and occlusive property of the SLNs. The current review is an attempt to focus on the characteristics of solid lipid nanoparticles, methods for the preparations, and their cosmetic applications along with some future perspectives of the nanodrug delivery systems. A review of the current literature of solid lipid nanoparticles (SLNs) as novel carrier showed better photoprotection in sunscreens. The disadvantages of conventional sunscreens can be overcome by incorporation of solid lipid nanoparticles. On comparing the lipid nanobased systems with traditional cosmetic products, the occlusion can be achieved without the use of paraffin and other greasy oils. The film formed by lipid nanoparticles will be smooth as compared to the inflexible films formed by the paraffin. Newer approaches may lead to even better results. They also possess excellent UV-blocking activity and showed better photoprotection.

Preparation and characterization of copper-coated polyester fabric pretreated with laser by magnetron sputtering

Laser treatment is a high-efficiency coating process with many advantages of stable performance, convenient operation and environmental friendly. In this study, an efficient method for the pretreatment of polyester fabric, based on exposure to the output from a CO2 laser, is investigated. Polyester fabrics were treated by laser and then copper films were coated on the surface of treated polyester fabrics by magnetron sputtering method. Copper-coated polyester fabrics were characterized by XRD and SEM. Contact angle, heat generation and electrical conductivity of copper coated polyester fabric were tested. The electrical conductivity, UPF value and contact angle of copper-coated polyester fabric with pretreatment of 6.5 W lasers are 0.239 Ω/sq, 147.4, and 128.5°, respectively. The temperature of copper-coated fabric can be kept at 25.8℃ using only 5 V. The results suggest that the copper-coated polyester fabric with pretreatment of laser has excellent electrical conductive property, hydrophobicity, UV blocking, and heat generation properties. The adhesion strength between copper coating and fibers is improved after laser treatment. Laser can be potentially used in pretreatment of fabrics before coating in the future.

Characteristics of cotton fabric modified with chitosan (CS)/cellulose nanocrystal (CNC) nanocomposites

The chitosan (CS)/cellulose nanocrystal (CNC) (0, 0.2. 0.5, 0.8 and 1wt%) nanocomposites were applied as modifier, and then deposited on the surface of cotton fabric via a pad-dry-cure method. The morphology, mechanical, hydrophilicity and ultraviolet (UV)-blocking properties of prepared fabrics were carefully investigated. The results showed that CS/CNC could obviously enhance the UV-blocking property of cotton fabric. CS/CNC0.5 fabric exhibited the most excellent UV-blocking property as well as good washing durability after 30 times water laundering, indicating CS/CNC could be used as efficient and durable UV blocker for cotton fabric. In addition, CS/CNC also can increase the mechanical property of cotton fabric; while decrease the hydrophilicity of cotton fabric.

Microbial production of coconut fiber nanolignin for application onto cotton and linen fabrics to impart multifunctional properties

Lignin is the second most abundant renewable carbon source available on Earth. It is available in plenty as a by-product of pulp and paper industries, but it has largely been discarded. In this work, controlled microbial hydrolysis process was employed to produce nanolignin from the bulk lignin extracted from coconut fibers. The ligninase secreting fungal isolate, Aspergillus nidulans was used for this purpose. The size reduction of lignin was monitored by DLS nanoparticle size analyzer and, once the size reached below 100 nm, the nanolignin was purified and characterized. Nanolignin (size: 27.5 nm ± 2.7 nm) was applied onto the surface of cotton and linen fabrics by pad-dry-cure method using acrylic binder and characterized by FTIR, SEM and XRD. The finished cotton and linen fabrics showed excellent antibacterial (as per AATCC-100 standard method), UV blocking (as per AATCC-186 standard method) and antioxidant (as per DPPH method) properties. This work demonstrates the newer application of microbial produced nanolignin for multifunctional finishing of cotton and linen fabrics.

Anti-UV Radiation Textiles Designed by Embracing with Nano-MIL (Ti, In)-Metal Organic Framework.

Protective textiles against harmful solar radiation are quite important materials for outdoor workers to secure their skin from several diseases. Current report focuses on production of anti-ultraviolet radiation (UVR) textiles by incorporation of nano-metal-organic frameworks (n-MOFs). Two different MIL-MOFs, namely, MIL-68(In)-NH2 and MIL-125(Ti)-NH2, were immediately formed inside natural textiles (cotton and silk) matrix in nano size using quite simple and one-pot process. The formation of n-MIL-MOFs inside textiles were confirmed by using electron microscope and X-ray diffraction. Different size and morphology were seen depending on textile type reflecting the textiles' chemical composition role in the nature of prepared MIL-MOFs. For MIL-68(In)-NH2, particles with size distribution of 70.6-44.5 nm in cotton and 81.3-52.2 nm in silk were detected, while crystalline disc of MIL-125(Ti)-NH2 was clearly seen inside textiles. The natural textiles exhibited full UVR blocking after modification, and the UV protection factor (UPF) was linearly proportional with MIL-MOFs and metal contents. Whatever metal type, direct incorporation of MIL-MOF contents greater than or equal to 10.4 g/kg was sufficient to attain excellent UV blocking property. Although 38.5-41.0% of MIL-MOFs was lost during five washings, the washed samples showed very good blocking rate (UPF = 26.7-36.2) supporting good laundering durability.

Preparation of PBO/ZnO fibers by hydrothermal synthesis method and its properties

In this article, zinc oxide (ZnO) nanoparticles were synthesized and deposited on the surface of PBO fibers through hydrothermal synthesis method. The structures and properties of PBO/ZnO fibers and PBO fibers were characterized by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS), x-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Thermogravimetric analysis (TG), and tensile testing. The results revealed that the PBO/ZnO fibers have good mechanical properties and high thermal stability. Moreover, the fibers exhibited excellent UV-blocking properties by putting them under UV irradiation of 313 nm. Specifically, ZnO coated fibers will lose only 18.93% of tensile strength after 50 h irradiation, and then will keep over 65% of tensile strength after 100 h UV irradiation. Additionally the interface shear strength is increased significantly, and the results also showed modified PBO fibers exhibited excellent hydrophobic quality. So the functional materials have great potentials in future engineering applications.