anti-UV Performance Research Articles

Unexpected self-healing acceleration within urethane networks: lignosulfonate mediation of ionic and hydrogen bonds for ultra-strong recyclable elastomers

Stiff structures are generally considered detrimental to the materials’ self-healing efficiency because of the rigid conformation and restricted motion of the molecular chains. However, in this study, an unexpected acceleration in self-healing was observed in a urethane network when lignosulfonate, a bio-based stiff structure with stiff benzene rings, was introduced into the polyurethane matrix. An extraordinary increase in mechanical properties was achieved with just 3 wt% lignosulfonate added to the pristine sample, including a strength increase from 16.24 MPa to 42.89 MPa and elongation at break from 390% to 602%. Importantly, this significant enhancement in mechanical properties was accompanied by a notable acceleration in healing time efficiency, which increased by up to 44% compared to the pristine sample. This unique behavior can be attributed to the mediation of lignosulfonate on the ionic bonds between lignosulfonate and the urethane segment, as well as the hydrogen bonds formed within the urethane segments. This mediation ensures ultra-high strength without compromising the self-healing capacity and opens a way for accelerating elastomers self-healing efficiency through lignosulfonate, a readily available biomass-derived material. In addition, the addition of lignosulfonates gives the elastomer some Anti-UV performance.

Fully biobased approach for sustainable flame retardancy, antibacterial and anti-UV modification of silk fabric

The versatile modification of silk fabric using a fully biobased approach is intriguing. In this study, phytic acid and vanillin, which are plant extracts, were utilized to synthesize reactive vanillin phytate ester for modifying silk fabric to achieve durable flame retardancy, antibacterial and anti-UV performance. The multifunctional properties, thermal resistance, smoke and heat suppression capacity, flame-retardant durability and mechanism of modified silk fabrics were investigated. The vanillin phytate ester imparted high antimicrobial and UV resistance to silk fabric, achieving a 97 % inhibition rate against Escherichia coli and reaching an “excellent” level of UV protection. The modified silk fabric also possessed the self-extinguishing capacity, with a limiting oxygen index value as high as 33.5 %. There was also a significant reduction of 71.7 % in peak heat release and 40 % in smoke release compared with those of the original silk. After undergoing 20 washing cycles, the modified silk fabrics also self-extinguished and passed the vertical burning test, and such good washing resistance was achieved by the Schiff base cross-linking of vanillin phytate ester on the silk fabric. An intumescent flame-retardant mechanism was also identified by char residue analyses, which was driven by the synergistic charring action of phosphate groups and aromatic structures.

Fabrication of multifunctional bio-macromolecule organic-inorganic hybrid system for protein silk: Photochromic, UV protection, fire-proof and super durability

Nowadays, high value-added and multifunctional textiles have attracted widespread attention due to the changing demands of modern life. This study focused on the fabrication of silk with photochromism, flame retardancy, UV resistance and durability using riboflavin sodium phosphate (RSP) and various metal ions (Fe2+, Fe3+, Al3+, and Ti4+). Attractively, the photochromic performance was one of the most distinctive features of the modified silk, and the yellow silk fabric turned into fluorescent green under UV lamp. After a detailed comparison, it was determined that RSP/Fe3+ hybrid system was most effective in improving anti-UV performance of the silk with a high UPF of 25.8, achieving a “Good” level of UV protection. Specifically, it achieved a B1 fire protection with a low damaged-length of 9.4 cm and a high LOI of 28.3 %. Additionally, the modified silk showed the lowest smoke density, reducing by approximately 84.1 % versus that of pristine silk. Moreover, the modified silk was able to meet the B1 classification and the “Good” UV protection requirements even after 75 washing cycles, making it more durable than most functional textiles reported. The further analysis indicated that RSP and metal ions can synergistically enhance the condensed-phase action, thereby improving the fire resistance of silk.

Multi-Functional Electrospun AgNO3/PVB and Its Ag NP/PVB Nanofiber Membrane.

This study focuses on the fabrication of fiber membranes containing different concentrations of AgNO3 via the electrospinning technique. The AgNO3 present in the fibers is subsequently reduced to silver nanoparticles (Ag NPs) through UV irradiation. The resulting nanofiber film is characterized using scanning electron microscopy, X-ray diffraction, and evaluations of its anti-UV and anti-electromagnetic radiation properties. Experimental results demonstrate that increasing the AgNO3 content initially decreases and then increases the fiber diameter and fiber diameter deviation. Under UV light, the nanofibers fuse and bond, leading to an increase in the fiber diameter. AgNO3 is effectively reduced to Ag NPs after UV irradiation for more than 60 min, as confirmed by the characteristic diffraction peaks of Ag NPs in the XRD spectrum of the irradiated AgNO3/PVB fibers. The nanofiber film containing AgNO3 exhibits superior anti-UV performance compared to the film containing AgNO3-derived Ag NPs. The anti-electromagnetic radiation performances of the nanofiber films containing AgNO3 and AgNO3-derived Ag NPs are similar, but the nanofiber film containing AgNO3-derived Ag NPs exhibits higher performance at approximately 2.5 GHZ frequency. Additionally, at an AgNO3 concentration of less than 0.5 wt%, the anti-electromagnetic radiation performance is poor, and the shielding effect of the nanofiber film on medium- and low-frequency electromagnetic waves surpasses that on high-frequency waves. This study provides guidance for the preparation of polyvinyl butyral nanofibers, Ag NPs, and functional materials with anti-ultraviolet and anti-electromagnetic radiation properties.

Bioinspired Formation of Anti-Ultraviolet Micro-Goose Bump PDMAEMA/PS Coatings.

In this paper, inspired by the human-giving goosebumps process, we demonstrated a rapid, versatile, and simple method to prepare anti-UV microstructures polymer blend films with good morphology based on phase separation. Through the results of characterizations, it is proved that the microstructures are formed by polymer phase separation. Then the formation possibility of microstructures is proved by thermodynamic analysis. Moreover, the phase-field model is used to simulate the formation of microstructures by the finite element method, which can illustrate the evolution process of the microstructures. Besides, the microstructures were prepared on different substrates through the simple phase separation method, which can verify the versatility of this method. In addition, the anti-UV performance of the micro-structure films was evaluated. This work proposed a simple and versatile route to prepare microstructures coating in different substrates, which exhibit well anti-UV performance, and this work has the application potential for preventing material aging caused by UV radiation.

Synthesis of vanillin-based porphyrin for remarkably enhancing the toughness, UV-resistance and self-extinguishing properties of polylactic acid

To achieve high-performance polylactic acid (PLA) composites, the exploitation of multifunctional biomass additives derived from renewable resources are highly demanded. Herein, a vanillin-based porphyrin (VPR) was designed and synthesized to impart PLA with enhanced mechanical, anti-UV, and flame retardant properties. Multiple intermolecular interactions between VPR and PLA enabled significant toughening of the PLA/VPR biocomposites compared to PLA itself. The elongation at break and impact strength for PLA/3VPR were improved by 88.2 % and 104.2 %, respectively, without influence on their tensile strength. Furthermore, the PLA/VPR biocomposites exhibited improved anti-UV performance with only 1.5 % and 8.6 % decrease of the strength and elongation at break respectively after UV aging. More importantly, incorporation of only 3 wt% VPR loading within the PLA/3VPR composite allowed for excellent self-extinguishing with a UL-94 V-0 level, greatly improving the versatility of PLA composites. We envision that such bio-based PLA/VPR materials with multifunctional features will extensively broaden the usable range of PLA composites.

Study on Structure and Anti-UV Properties of Sericin Cocoons

Abstract Through biogenetic engineering, the posterior silk glands of Bombyx mori larvae are degenerated, and only the middle silk glands are retained to secrete sericin to produce sericin fibers, so as to obtain sericin cocoons with high sericin content (>98.5%). For this paper, sericin cocoons were studied, and the morphological structure characteristics and properties of sericin cocoons and common Bombyx mori cocoons were compared and analyzed through such modern test techniques as SEM, FTIR, and XRD. Results show that sericin cocoons have the basic morphological structure of cocoons, but because of the brittleness and hardness of sericin, the ssericin cocoons have poor integrity with a thermal decomposition rate that is higher than that of cocoons; the two cocoons are of a similar protein structure, with both α-helix and β-sheet structures, and dominantly the β-sheet structure; and the crystallinity of sericin cocoons (10.48%) is lower than that of the common Bombyx mori cocoons (27.10%). Sericin was extracted from both cocoons to obtain a mixed sericin solution respectively, which were coated on base fabrics of polyester taffeta (210T) for coating finish and subjected to qualitative research for their anti-UV properties. The base fabrics coated with mixed sericin solutions of sericin cocoons and Bombyx mori cocoons have an anti-UV performance index (UPF) of 23.9% and 22.5% respectively, which are higher than that of the base fabric (8.9%)..

Colorless, Transparent, and High-Performance Polyurethane with Intrinsic Ultraviolet Resistance and Its Anti-UV Mechanism

Polyurethane (PU) is a widely used polymer material that will age under prolonged exposure to ultraviolet (UV) light, shortening the service life. Several methods have been used to prepare the anti-UV PU, including adding nonreactive anti-UV additives, functional fillers, and biological antioxidant molecules. However, the nonreactive anti-UV additives may migrate during long-term use, the functional fillers may damage the mechanical properties and seriously reduce the light transmittance of the sample, and the biological antioxidant molecules will inevitably color the sample. To solve these problems, in this work, a benzotriazole UV absorber (Chiguard R-455) was introduced into the PU molecular chains by in situ polymerization to prepare the nonmigrating intrinsic anti-UV PU sample with high performance and colorless transparency. The anti-UV PU samples exhibit light transmittance of over 88% in the visible range and superior mechanical properties with tensile strength higher than 65 MPa and elongation at break higher than 900%. After 24 h UV irradiation (200 W, 365 nm), the tensile strength and elongation at break of pure PU sample are significantly reduced to only 8.9 and 15.8% of the original one, respectively. On the contrary, the addition of Chiguard R-455 will endow the PU sample with excellent anti-UV performance. After 24 h UV irradiation, the tensile strength (67.2 ± 1.6 MPa) and elongation at break (917.4 ± 30.0%) of PU-0.5% (the content of Chiguard R-455 is only 0.5 wt %) have changed little compared with the sample without irradiation (67.4 ± 3.5 MPa and 919.4 ± 26.5%). Additionally, the anti-UV mechanism of the PU sample is systematically studied. This work provides a feasible method for preparing colorless, transparent, high-performance, nonmigrating intrinsic UV-shielding PU samples, which can be used as a UV light-shielding material in various fields with visible and aesthetic requirements, such as protection fields and wearable products.

Lignin nanoparticle reinforced multifunctional polyvinyl alcohol/polyurethane composite hydrogel with excellent mechanical, UV-blocking, rheological and thermal properties

In this study, we innovatively synthesized a multifunctional PVA/PU-LNP composite hydrogel with integrated distinguished UV-blocking, mechanical strength, dynamic viscoelasticity and thermal properties by introducing lignin nanoparticle (LNP) into polyvinyl alcohol (PVA) and polyurethane (PU) mixed matrix through freeze-thaw cycle. The rigid porous network structure was established by hydrogen bond interactions among the well-distributed LNP and PVA/PU molecular chains, which endowed excellent mechanical strength, viscoelasticity, thermal stability and flexibility with PVA/PU-LNP composite hydrogel. The elongation at break and tensile strength of PVA/PU-LNP composite hydrogel were markedly improved from 227.3 % and 247.1 KPa to 460.1 % and 950.4 KPa with the LNP loading of 2 % based on PVA weight, respectively. Meanwhile, PVA/PU-2%LNP hydrogel exhibited prominent compressive resistance and pleasing shape recovery capability. Moreover, the blending of LNP at a low dosage (0.5 %) based on PVA weight effectively shielded 99.34 % of UV light and penetrated 42.27 % of visible light, indicating that PVA/PU-LNP composite hydrogel demonstrated outstanding anti-UV performance. In addition, the incorporation of LNP caused a remarkable decline in the pore size of PVA/PU-LNP composite hydrogel (4.39 ± 0.46 μm to 1.54 ± 0.22 μm), which slightly reduced water uptake capacity of composite hydrogel. Therefore, this work provided a new approach to constructing a multifunctional composite hydrogel.

Study on physical properties of four pH responsive Spodoptera exigua multiple nucleopolyhedrovirus (SeMNPV) microcapsules as controlled release carriers

This study provides a promising controlled release form of nuclear polyhedrosis virus (NPV) for targeted control of lepidopteran pests. However, the application of NPV is limited due to its sensitivity to UV inactivation. This study investigated the anti-UV properties of microcapsules of SeMNPV occlusion bodies (OBs) encapsulated by calcium alginate (CA), and also the influence of the modification of CA by chitosan (CS), whey protein (WP), and polydopamine (PDA). These capsules were used to deliver, in a controlled release manner virions under alkaline pH conditions. Characterization of the structure, morphology, particle size, encapsulation efficiency, contact angle, insecticidal activity, UV resistance and in vitro release of the microcapsules was conducted. The modified microcapsules had better sphericity, and were devoid of SeMNPV OBs on the surface. The encapsulation rate was 84.76 ± 0.59%. PDA@CA-NPV had the highest wettability and the contact angle was 74.51 ± 0.53°. The 50% lethal concentration values (LC50) of CA-NPV, CS@CA-NPV, WP@CA-NPV and PDA@CA-NPV were 11.5, 10.7, 10.5 and 1.2 times that of SeMNPV OBs alone. The modified microcapsules all improved the anti-UV performance of the virus, and PDA@CA-NPV was the most UV-resistant. Using qPCR, it was observed that under alkaline conditions, a large number of virions were released from PDA@CA-NPV, CA-NPV and SeMNPV OBs. Microencapsulated virus under alkaline conditions did not change the release pattern of virions.

Strategy of Integrating Ultraviolet Absorption and Antimicrobial Activity in a Single Molecule: DFT Calculation and Experiment.

In the present study, (3,5-benzamide-2,4-dihydroxyphenyl)(phenyl) methanone (UV-CB) was synthesized and investigated as an ultraviolet (UV) absorber and a bacteriostatic agent. The optimized geometry, energy levels, charges, and UV electronic absorption bands of UV-CB in the singlet were calculated by density functional theory (DFT) calculations. The quantum chemical method was used to investigate the geometry and natural bond orbital (NBO) parameters. And the computational studies indicated that the intramolecular hydrogen bond (IMHB) was formed between the 2,4-dihydroxybenzophenone (UV-C) group and the N-(hydroxymethyl)benzamide (NBA) group, which was beneficial to the stability after the combination. The results of the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) tests illustrated that UV-CB is a promising antibacterial agent. The successful synthesis of UV-CB with anti-UV performance and antibacterial ability evidences that DFT calculation is an available approach to design and analyze novel compounds.

Grafting natural nicotinamide on tempo-oxidized cellulose nanofibrils to prepare flexible and transparent nanocomposite films with fascinating mechanical strength and UV shielding performance

Light pollution from ultraviolet (UV) radiation is gaining growing concerns, as the emissions and burning of fossil fuels destroyed the ozone layer. Seeking a solution against skin exposure to excessive radiation is an urgent requirement. In this study, nicotinamide (NA), the main component of vitamin B3, was introduced as a new modifier into Tempo-oxidized cellulose nanofibrils (TOCNFs) together with the physical cross-linking with tannin acid (TA) to improve anti-UV performance of the nanocomposite films. Incorporation of NA into the films presents distinguished UV shielding capability UVB wavelength range from 200 nm to 320 nm (NTA1–5) due to the introduced functional groups like CO and benzene rings. Moreover, mechanical properties were notably enhanced, which overcome the low strength of common nanocellulosic materials. The stress increased from 69.8 MPa to 116.3 MPa, and the toughness can reach 131.58 MJ/m3 by tuning the additional amount of NA. Meanwhile, TGA and DTG analysis demonstrated that the incorporation of amide bonds and TA into the composite films greatly improved the thermal stability. Thus, the proposed materials fabricated from natural biomolecules show great potential in serving as new kinds of UV-resistant products in the application areas of sunscreen, protective clothing, and building materials.

Carbon Dots Embedded in Cellulose Film: Programmable, Performance-Tunable, and Large-Scale Subtle Fluorescent Patterning by in Situ Laser Writing.

Fluorescent patterns with multiple functions enable high-security anti-counterfeiting labels. Complex material synthesis and patterning processes limit the application of multifunctional fluorescent patterns, so the technology of in situ fluorescent patterning with tunable multimodal capabilities is becoming more necessary. In this work, an in situ fluorescent patterning technology was developed using laser direct writing on solid cellulose film at ambient conditions without masks. The fluorescent intensity and surface microstructure of the patterns could be adjusted by programmable varying of the laser parameters simultaneously. During laser direct writing, carbon dots are generated in situ in a cellulose ester polymer matrix, which significantly simplifies the fluorescent patterning process and reduces the manufacturing cost. Interestingly, the tunable fluorescent intensity empowers the fabrication of visual stereoscopic fluorescent patterns with excitation dependence, further improving its anti-counterfeiting performance. The obtained fluorescent patterns still show ultrahigh optical properties after being immersed in an acid/base solution (pH 5-12) over one month. In addition, the anti-UV performance of the obtained laser-patterned film with transmittance around 90% is comparable to that of commercial UV-resistant films. This work provided an advanced and feasible approach to fabricating programmable, performance-tunable, subtle fluorescent patterns in large-scale for industrial application.

Preparation of superhydrophobic paper mulch and study on its anti-UV performance

In order to improve the shortcomings of paper mulch, such as the low water resistance and weather fastness in practical application, the paper mulch with a superhydrophobic structure was prepared by depositing zinc oxide layer and silicon dioxide layer on the surface of paper mulch by the solution impregnation method, the paper mulch surface treatment method is simple and environmentally friendly. The surface chemical composition and surface morphology of paper mulch before and after UV aging were characterized, respectively. The wetting property, bouncing property, and mechanical stability of paper-based film were studied. The results showed that the static contact angle of the superhydrophobic paper mulch was as high as 161.77°, and the average sliding angle was only 3.5°, which also showed excellent droplet bounce performance and mechanical stability. After UV aging experiment, the static contact angle of super-hydrophobic paper mulch was increased to 163.64°, and the sliding angle was reduced to 2.5°. Its excellent performance could still be maintained, showing excellent UV resistance, which improved the weather fastness and water resistance of paper mulch to a certain extent, and laid a foundation for the next large-scale field test.

Highly transparent biaxially oriented poly(ester amide) film with improved gas barrier properties and good mechanical strength

Poly(ethylene terephthalate) (PET) reinforced with hydrogen bonding is prepared by incorporating 4 mol% amide units formed by 1,12-dodecanediamine and terephthalic acid. Structurally modified PET (PETA) containing amide units is extruded and biaxially stretched to make biaxially oriented (BO) PETA films with high performance. The formation of hydrogen bonds in BOPETA is detected, and the effect of the incorporated amide units on the performance is discussed. Attractive interchain forces are increased through the hydrogen bonds formed in BOPETA, and its crystallinity and mechanical properties are improved. The fabricated BOPETA film exhibits lower water and oxygen permeabilities than that of BOPET because the free volume was reduced. The optical properties of the BOPETA film remain good after incorporating amide units into the PET backbone, and its light transmittance reaches 88.8%. Moreover, BOPETA with 4 mol% amide units absorbs somewhat ultraviolet (UV) light and exhibits slight anti-UV performance. A facile approach for the preparation of PET films with good mechanical strength, high transparency, and improved gas barrier properties for packaging is discussed in this work.

Structure and Functions of Cocoons Constructed by Eri Silkworm.

Eri silkworm cocoons (E cocoons) are natural composite biopolymers formed by continuous twin silk filaments (fibroin) bonded by sericin. As a kind of wild species, E cocoons have characteristics different from those of Bombyx mori cocoons (B cocoons). E cocoons have an obvious multilayer (5–9 layers) structure with an eclosion hole at one end and several air gaps between the layers, which can be classified into three categories—cocoon coat, cocoon layer, and cocoon lining—with varying performance indexes. There is a significant secondary fracture phenomenon during the tensile process, which is attributed to the high modulus of the cocoon lining and its dense structure. Air gaps provide cocoons with distinct multistage moisture transmission processes, which form a good moisture buffer effect. Temperature change inside cocoons is evidently slower than that outside, which indicates that cocoons also have an obvious temperature damping capability. The eclosion hole does not have much effect on heat preservation of E cocoons. The high sericin content of the cocoon coat, as well as the excellent ultraviolet absorption and antimicrobial abilities of sericin, allows E cocoons to effectively prevent ultraviolet rays and microorganisms from invading pupae. The ultraviolet protection factor (UPF) of the E cocoon before and after degumming were found to be 17.8% and 9.7%, respectively, which were higher than those of the B cocoon (15.3% and 4.4%, respectively), indicating that sericin has a great impact on anti-UV performance. In the cocoon structure, the outer layer of the cocoon has 50% higher content than the inner layer, and the E cocoon shows stronger protection ability than the B cocoon. Understanding the relationship between the structure, property, and function of E cocoons will provide bioinspiration and methods for designing new composites.

Facile immobilization of graphene nanosheets onto PBO fibers via MOF-mediated coagulation strategy: Multifunctional interface with self-healing and ultraviolet-resistance performance

The surface of poly (p-phenylene benzobisoxazole) (PBO) fibers with self-healing and ultraviolet (UV)-resistance performance play the key role in prolonging their service lifespan. Although great advances have been made in the single aspect of above two properties, integration of self-healing and anti-UV performance into the surface of PBO fiber is still a challenge. In this study, the coagulation strategy mediated by metal-organic framework (MOF) is proposed to construct the multifunctional surface of PBO fibers. The spindle-like iron (III)-based MOF (MIL-88B-NH2) nanocrystals are firstly immobilized onto the surface of PBO-COOH through hydrothermal reaction, then serving as the medium layer to further immobilize sufficient graphene oxide (GO) nanosheets. Benefitting from the favorable near-infrared (NIR, 808 nm) photothermal conversion performance of GO nanolayers, the monofilament composite-PBO@Fe-MIL-88B-NH2-GO-TPU (thermoplastic polyurethane) exhibited a stable and high self-healing efficiency (approximately 80%) within five cycle times. Meanwhile, the cooperative adsorption and shielding weaken effects of MOF-GO nanolayers enabled PBO fibers with excellent anti-UV properties that are superior to much reported literatures after 96 h aging time and eventually increased by 75% compared with untreated PBO fiber. In view of the varieties and multifunctionalities of MOFs and carbon nanomaterials, MOF-mediated coagulation strategy would provide guidance for preparing multifunctional composite materials.

Tailoring high anti-UV performance polypropylene based geotextiles with homogeneous waterborne polyurethane-TiO2 composite emulsions

Polypropylene (PP) geotextiles have a vital application value in high-cold frozen soil, high temperature and high humidity environment especially acidic/alkaline soil, however, solar radiation, especially ultraviolet (UV) radiations, is one of major factors responsible for their premature failure. Herein, we report a novel approach to synthesize high anti-UV performance PP geotextiles with enhanced mechanical properties. For this purpose, a highly stable composite emulsion was prepared by dispersing rutile TiO2 nanoparticles in deionized water and waterborne polyurethane (WPU) through a systematic optimization process. Afterwards, PP nonwoven was immersed in the optimized composite emulsion then padded and dried. Performance of WPU-TiO2 coated PP geotextiles was evaluated by accelerated weathering test, and coated geotextiles after 10 days of accelerating aging displayed an excellent UV-shielding performance by significantly alleviating the aging rate of PP geotextiles. Besides excellent anti-UV performance, WPU-TiO2 coated PP geotextiles also exhibited comparatively much higher residual breaking strength (52.44% in MD and 55.12% in CD) and residual breaking elongation (40.44% in MD and 42.19% in CD) than pristine PP geotextiles. This effective synthesis of high anti-UV shielding performance geotextiles opens new insights into the designing of new materials for development of efficient geotextiles.

Preparation and Characterization of Zein-Based Nanoparticles via Ring-Opening Reaction and Self-Assembly as Aqueous Nanocarriers for Pesticides.

Herein, we prepared and compared two water-soluble amphiphilic zein-based nanocarrier systems with avermectin (AVM) payload to enhance pesticide's water-dispersity, foliage wettability, adhesion, anti-UV, and pH-responsive controlled release property. Ethylene glycol diglycidyl ether (EGDE) and diethanolamine (DEA) were utilized to conjugate with hydrophobic zein via a ring-opening reaction and then encapsulated with AVM via a hydrophobic interaction to fabricate a nanopesticide marked as AVM@Zein-EGDE/DEA. For the sake of further improving the nanocarrier's performance, sodium carboxymethyl cellulose (CMC) was grafted with methyl methacrylate (MMA) and 2-hydroxyethyl methacrylate (HEMA) to form a kind of copolymer CMC-g-P(HEMA-MMA), which was applied to conjugate with Zein-EGDE via a ring-opening reaction. Likewise, another nanopesticide system named AVM@Zein-EGDE/CMC-g-P(HEMA-MMA) was obtained through hydrophobic interactions as well as the electrostatic effect. Various techniques were utilized to confirm chemical interaction, thermal behavior, structural characteristics, and stability. The results showed that AVM encapsulated in Zein-EGDE/CMC-g-P(HEMA-MMA) possessed a larger particle size with an average value of 180-254 nm than AVM loaded in Zein-EGDE/DEA with 144-175 nm but had better stability in aqueous solution. Also, AVM loaded in Zein-EGDE/CMC-g-P(HEMA-MMA) enhanced the encapsulation efficiency, and both of them exhibited excellent pH-responsive sustained release behavior. Besides, the former improved wettability on a cucumber leaf surface and enhanced adhesion ability compared to AVM@Zein-EGDE/DEA because of CMC-g-P(HEMA-MMA) with hydrophobic segments. Similarly, anti-UV performance was also enhanced owing to CMC-g-P(HEMA-MMA) as an additional protective layer. More importantly, the encapsulation of Zein-EGDE/DEA and Zein-EGDE/CMC-g-P(HEMA-MMA) as protective barriers for AVM still retained a similar toxicity level. Overall, we demonstrated the proof of concept for the application of amphiphilic zein-based nanomaterials as aqueous nanocarriers for hydrophobic pesticides.

A Versatile Sunscreen with Minimal ROS Damage and Low Permeability.

Organic and inorganic ultraviolet (UV) filters possess themselves advantages, while they suffer from different limitations including photostability, penetration, and cytotoxicity. Integrating organic and inorganic UV filters in a single unit holds great potential for enhanced UV protection. Herein, the dendritic silicon dioxide microspheres (DSMs) are encapsulated with Bi2Ti2O7 nanocomposites (BTO-DSMs), an inorganic filter, and decorated with organic filters including sinapoyl malate (SM) and baicalin (BS/BTO-DSM) to enhance UV protection while significantly reducing ROS and skin permeability under UV exposure. The inorganic BTO-DSM component presents an expanded UV shield range and suppressed photocatalytic properties while preventing the organic filter SM direct contact with the epidermis and penetration behaviors. The baicalin efficiently scavenges the generated ROS from SM and reduces the transmittance of blue light. Notably, the results show that the proposed combined system significantly broadens the UV absorption region. Thus, the BS/BTO-DSM presents advanced in vitro anti-UV performance and in vivo UV protection against keratinocyte apoptosis and epidermal hyperplasia without long-term toxicity. The excellent anti-UV properties coupling with the suppressed photocatalytic capability and minimal epidermal penetration of BS/BTO-DSM make it promising for skin protection.