Water Contact Angle Research Articles

Construction of glycosylated zein-based colloids to simultaneously improve fucoxanthin’s thermal processing adaptability, digestive stability, and oral bioavailability

Fucoxanthin (FX) is a carotenoid found in marine environments with a range of nutritional functions. However, its application in the food industry has been restricted by its vulnerability to deterioration and absorption challenges. This study employed zein to develop hydrophilic colloids to enhance the thermal processing adaptability, gastrointestinal digestive stability, and oral bioavailability of FX. The findings demonstrated that the using glucose for the grafting modification of zein caused a deviation in its isoelectric point, reduced its water contact angle, and altered its secondary structure, resulting in higher hydrophilicity. Using glycosylated zein (GZ) for FX loading yielded homogenous, stable aqueous GZ-FX complex dispersion solutions with an encapsulation efficiency (EE) > 85.00%, a particle size < 210.00nm, a zeta-potential > -30.00mV, and a polydispersity index (PDI) < 0.30. GZ-based encapsulation notably enhanced the thermal stability of FX, retaining approximately 90.00% and 80.00% of the FX at 65 ℃ and 100 ℃, respectively. During in vitro simulated gastrointestinal digestion, GZ-encapsulation of FX demonstrated a retention increase of 30.63% and a 2.31-fold higher micellization rate. The in vivo absorption results showed that GZ-based encapsulation dramatically increased FX oral bioavailability, while its serum, liver, and kidney response levels were 51.49-fold, 5.13-fold and 6.73-fold higher. This study suggests that glycosylated alcohol-soluble proteins are highly effective carriers for delivering carotenoids, with significant application potential in the food industry.

Mechanical properties, gas permeability and biodegradation mechanism of biobased poly(ester amide)s from 2,5-furandicarboxylic acid and amido diols for sustainable food packaging

The aim of this work was to evaluate the functional properties of a family of poly(ester amide)s (PEAs) for flexible food packaging applications. The polymers under study were previously synthesized via random copolymerization of furan 2,5-dicarboxylic acid (2,5-FDCA) with different amounts of 1,10-decanediol and an amido diol (AD 46). Poly(decamethylene furanoate) (PDF) and poly(ester amide) 46 (PEA 46) were the reference homopolymers. PEA copolymers were compression molded into films and subjected to WAXS, DSC, SEM analyses and water contact angle, mechanical, gas barrier tests. The results showed a remarkable improvement in the functional properties of PEAs compared to those of PDF, with a decrease up to about 50% of O2 and CO2 transmission rates, which were found to be comparable to those of commercial PET. The mechanical properties of PEAs were also improved in comparison with PDF because of the increased toughness and higher resistance to plastic deformation, paired with elongation at break up to 650%. In order to assess the effects of contact with food, the prepared films were treated with food simulants. Moreover, the films were stored in conditions of controlled temperature and humidity, chosen to replicate real scenarios of application involving aggressive environmental conditions. After contact with food simulant liquids, the materials became more rigid and less ductile, but their gas barrier properties remained superior to those of commercially widespread polyolefins. Finally, films were subjected to composting tests: the higher the amido diol content, the faster the degradation rate, which occurred via a mechanism of bulk hydrolysis, because of the higher hydrophilicity of amide groups. Overall, the results highlighted the potential of PEA copolymers for the production of biobased, sustainable, flexible food packaging.

Mucus-inspired lubricative antibacterial coating to reduce airway complications in an intubation cynomolgus monkey model

Endotracheal intubation-related complications are common in clinical, and there are currently no effective strategies to address these matters. Inspired by the biological characteristics of human airway mucus (HAM), an artificial airway mucus (ARM) coating is straightforwardly constructed by combining carboxymethyl chitosan with methyl cellulose. The ARM coating exhibited excellent lubricity (coefficient of friction (CoF) = 0.05) and hydrophilicity (water contact angle (WCA) = 21.3°), and was capable of coating both the internal and external surfaces of the endotracheal tube (ETT). In vitro experiments demonstrated that the ARM coating not only showed good broad-spectrum antibacterial activity, but also significantly reduced nonspecific protein adhesion. Through an in vivo intubation cynomolgus monkey model, ARM-coated ETT potently mitigated airway injury and inflammation, and was highly potential to prevent bacterial infection and catheter blockage. This work offers a promising avenue for the development of airway-friendly invasive devices.

Preparation and study of polyvinylidene fluoride film with high UV aging resistance

Abstract Polyvinylidene fluoride materials were widely used in the preparation of solar panel films due to their excellent weather resistance and heat resistance. In this work, Polyvinylidene fluoride films with UV absorbers (PF/UV films) were prepared by customized extrusion equipment. The properties of these films were demonstrated with a scanning electron microscope (SEM), water contact angle (WCA), thermogravimetric analyzer (TGA), differential scanning calorimetry (DSC), and tensile strength tester. Furthermore, the SEM observation suggested that PF/UV films had smooth surfaces without significant defects. The WCA results illustrated that PF/UV films had better hydrophobicity than polyvinylidene fluoride films. The TGA and DSC curves indicated that the initial decomposition temperature and the melting temperature of the PF/UV film were 365.1°C and 169.2°C, respectively. Furthermore, the results of UV transmittance indicated that the UV aging resistances of PF/UV film were higher than that of polyvinylidene fluoride film.

Development of carboxymethyl cellulose/starch films enriched with ZnO-NPs and anthocyanins for antimicrobial and pH-indicating food packaging

Active packaging, which can monitor food freshness and extend the shelf life, has gained significant attention in recent years. This study aims to develop a novel carboxymethyl cellulose (CMC)/starch/anthocyanins/ZnO active films with enhanced properties and specific functionalities. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed that the addition of anthocyanins and nano-ZnO particles (ZnO-NPs) led to heterogeneous microstructures and a slight decrease in the crystallinity. Fourier transform infrared spectroscopy (FTIR) indicated that there were no chemical interactions among film components. Active films containing ZnO-NPs exhibited improved ductility, as well as enhanced light barrier and water resistance properties. Notably, a shift from hydrophilic to hydrophobic behavior of the films was observed with high ZnO-NP content, as evidenced by a significant increase in the water contact angle (from 63.44° to 114.22°). Furthermore, the presence of only 1 % ZnO-NPs resulted in efficient inhibition of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) growth. Moreover, active films containing both anthocyanins and ZnO-NPs were highly sensitive to pH changes in buffer solutions (pH 2–11). Based on the results, a recommended film formulation for future active packaging applications is a 80:20 CMC/starch blend with 3 % ZnO-NPs and 0.1 g anthocyanins.

Development of SBS composite modified asphalt incorporating polydopamine-enhanced MoS2

This study investigated the development of a novel composite modified asphalt incorporating PDA-MoS2 into styrene-butadiene-styrene (SBS) modified asphalt. The successful synthesis of PDA-MoS2 was confirmed through various characterization techniques. The incorporation of PDA-MoS2 into SBS modified asphalt resulted in significant improvements in performance properties. With a PDA-MoS2 content of 0.7 wt%, the modified asphalt showed a notable 15.1% rise in softening point and a 24% drop in penetration in comparison to the control SBS modified asphalt. Dynamic Shear Rheometer tests revealed a 2.4-fold increase in the rutting factor at 60°C. Multiple Stress Creep Recovery tests demonstrated enhanced rutting resistance, with a 72.2% reduction in nonrecoverable creep compliance at 0.1 kPa stress level. Electrochemical measurements showed improved corrosion resistance, evidenced by lower current densities and higher charge transfer resistance. Microstructural analysis revealed well-dispersed PDA-MoS2 particles forming a compact network structure within the asphalt matrix. The hydrophilicity of the modified asphalt increased, with a 35.3% decrease in water contact angle. The synergistic effect between PDA-MoS2, SBS, and asphalt components, facilitated by enhanced interfacial interactions and chemical bonding, contributed to the observed performance improvements. The results indicate that PDA-MoS2 has the potential to improve the characteristics of SBS modified asphalt as a modifier.

Evaluation of optical, thermal and hydrophobic properties of sustainable stilbene-based benzoxazines for high-performance utilization

Currently there is a growing interest in the field of photosensitive benzoxazines synthesized from sustainable raw materials. An attempt has been made to synthesize nine structurally different benzoxazines through Mannich condensation reaction. The formation of the expected structure of the synthesized benzoxazine monomers were ascertained using spectroscopic methods. The ring-opening polymerization of benzoxazines was studied using DSC and found that THS-imp benzoxazine monomer exhibits the lowest value of curing temperature (Tp) of 179oC than the rest of the benzoxazine monomers. Thermal stability of polybenzoxazines were analyzed using thermogravimetric analyzer. Among the different polybenzoxazines studied, poly(THS-a) possesses the higher thermal stability with char yield of 53% than that of other benzoxazines. The band gap values of benzoxazines calculated from optical studies are ranged between 3.92-4.71 eV. The hydrophobic behavior of the polybenzoxazines assessed using the water contact angle obtained from goniometer for both neat polymer matrix and benzoxazine coated cotton fabric. Results from the water contact angle infer that the benzoxazines coated cotton fabric exhibited 152o, which shows the superhydrophobic behavior. The corrosion resistant properties of all the polybenzoxazines coated over MS specimen has been tested. Among them poly(THS-pfsa) and poly(THS-imp) have higher Icorr value and corrosion inhibition efficiency of 99%. Data obtained from different studies indicate that the benzoxazines developed from sustainable stilbene can be utilized in the form of coatings, adhesives, sealants, and matrices for composites for wide range of industrial and engineering applications, where high thermal stability and are required.

Electrically-modified bacterial cellulose tailored with plant based green materials for infected wound healing applications

Effective treatment of infected wounds remains a challenge due to the rise of antibiotic-resistant microorganisms. The development of advanced materials with strong antimicrobial properties is necessary to address this issue. In this study, a unique composite of electrically modified bacterial cellulose (EBC) with allantoin (ABC) and zein was developed by dipping diffusion method. Morphological structural analysis revealed a uniform distribution of zein and aligned fibers, confirming the synthesis of the ABC-Zein composite. The formation of ABC-Zein was further confirmed by attenuated total reflection-Fourier transform infrared (ATR-FTIR), which displayed additional peaks corresponding to EBC, indicating the incorporation of zein into ABC. X-ray diffraction (XRD) analysis of ABC-Zein demonstrated a similar crystalline structure with EBC. The ABC-Zein showed mechanical integrity (tensile strength: 1.15 ± 0.21 MPa), thermal stability (degradation temperature: 290 °C), porous structure (porosity: 40.23 0.21 %), and hydrophilic (water contact angle: 53.3 ± 5.3°) properties. Furthermore, the antimicrobial agent terpinen-4-ol (T4O), derived from tea tree oil, was incorporated into the ABC-Zein composite. Biological studies confirmed the antimicrobial efficacy (Staphylococcus aureus inhibition: 88.5 ± 7.19 %) and biocompatible (cell viability: 84.95 ± 5.6 %, hemolysis: 4.479 ± 0.39 %) nature of the T4O-ABC-Zein composite. The combined effects of the aligned fiber structure, zein protein, and antimicrobial T4O significantly enhanced infected wound healing by day 7, promoting inflammatory response, granular tissue formation, cell proliferation, and angiogenesis. By day 14, T4O-ABC-Zein facilitated complete wound healing, with reepithelization, collagen I deposition, and downregulation of CD 31, Ki67, and α-SMA. Overall, the innovative T4O-ABC-Zein composite, with an aligned fiber structure, improved biocompatibility, and antimicrobial properties, holds significant potential for the treatment of infected wounds.

High-strength, super-hydrophilic alginate electrospun nanofibrous membranes for rapid oil-water emulsion separation

Ultrafiltration membrane separation technology is considered an effective method for separating oil-water emulsions. However, oil droplets can easily deposit on the surface of the membranes, leading to severe fouling and a decrease in flux. In this study, poly (ethylene oxide)/acrylamide/sodium alginate (PEO/AM/NaAlg) hydrogel nanofibers were deposited on a poly (hydroxybutyric acid) (PHB) electrospun nanofibrous membrane. Subsequently, superhydrophilic (ethylene oxide)-poly(acrylamide)/calcium alginate hydrogel nanofiber composite filtration membranes (PEO/PAM/CaAlg-PHB) were prepared by polymerization and Ca2+ cross-linking using a PHB electrospun nanofibrous membrane as the matrix. The morphology, tensile strength, water contact angle, and oil–water emulsion separation properties of the PEO/PAM/CaAlg-PHB hydrogel filtration membrane were investigated. The results showed that the PEO/PAM/CaAlg-PHB membrane had good anti-fouling performance, with a tensile strength of 1.95 MPa. After 3 h of the filtration operation, the stable flux and oil–water emulsion rejection of the membrane reached 2925.2 L m−2 h−1 bar−1 and 98.66 %, respectively. The preparation method was simple, cost effective, and environmentally friendly, without introducing any organic pollutants. The PEO/PAM/CaAlg-PHB hydrogel filtration membrane shows promise for separating oil–water emulsions.

ZrO2 Nanoparticles Filler-Based Mixed Matrix Polyethersulfone/Cellulose Acetate Microfiltration Membrane for Oily Wastewater Separation

Membrane technology has emerged as a dynamic field of study in academia and industry for treating produced oily wastewater. ZrO2 nanoparticles (ZrO2 NPs) filler-based mixed matrix polyethersulfone/cellulose acetate microfiltration membranes were fabricated and inspected in the oily wastewater remediation. The fabricated bare PES membrane, PES/CA blended polymers membrane, and PES/CA blended polymers incorporating ZrO2 NPs (ZrO2@PES/CA) membranes by phase inversion technique were inspected by field emission scanning electron microscopy, atomic force microscopy, Fourier-transform infrared spectroscopy, and measurement of water contact angle and porosity. The ZrO2@PES/CA membrane which consisted of 0.5 wt.% ZrO2 NPs (0.5%ZrPC) afforded increased hydrophilicity and reduced water contact angle from 70° for P membrane to 30.23°. Also, the 0.5%ZrPC membrane gave pure water flux of 88.89 L/m2.h, high oil rejection of 98.2% and showed remarkable antifouling capacity with a high flux recovery ratio of 89.3% and relative flux reduction of 34.3%. The effect of transmembrane pressure (1, 2, 3, and 4 bar), feed temperature (25, 40, and 50 °C), and an initial oil concentration (250, 500, 750, and 1000 mg/L) on the permeation flux and oil rejection of the 0.5%ZrPC membrane was investigated. The results revealed that ZrO2@PES/CA membranes have a significant potential for effective oil removal with high permeability and antifouling ability. The 0.5%ZrPC membrane confirmed its durability and reusability when kept an acceptable oil removal after 5 cycles.

Efficient synthesis of highly hydrophobic lignin nanoparticles and their application as nano fillers for multifunctional composite membranes

Controlling the hydrophobic behaviors of lignin nanoparticles (LNPs) is crucial and advantageous for their application as film Nano Fillers, yet it poses a significant challenge. Herein, we successfully developed a novel method for the preparation of LNPs with highly hydrophobic behaviors using ternary deep eutectic solution (DES)-H2O systems. The resulting LNPs exhibit a significantly reduced content of hydrophilic groups on their outer surface, leading to a zeta potential value of only −4.9 mV, and up to 140.0° of water contact angle (WCA). Afterwards, a “Dissolution-Restructuration” mechanism was proposed to explain the formation of the prepared LNPs. Firstly, DES demonstrates superior H-bonding capabilities, facilitating the complete disruption of inter- and intramolecular H-bonding in lignin, and resulting in the formation of a highly homogenized lignin network. Subsequently, the DES system undergoes compromise after adding water, triggering the reformation of both inter- and intramolecular H-bonding and π-π interactions. Consequently, lignin orderly self-assembles into LNPs with highly hydrophobic characteristics. Especially, using the as-prepared LNPs as Nano fillers, a series of LNPs-containing polyvinyl alcohol (PVA) films were successfully fabricated, exhibiting exceptional hydrophobic behaviors (with contact angles reaching up to 124.0°). Furthermore, the mechanical strength, UV-shielding capabilities, and biodegradability of the PVA films are significantly enhanced. This study introduces a sustainable and efficient approach for the synthesis of hydrophobic LNPs, thereby facilitating the broadening of applications for lignin-based functional composite film materials.

Simple fabrication of breathable poly (vinylidene fluoride) fibrous membranes decorated by silica nanoparticles with enhanced waterproof property

In recent years, scientists have undertaken various preparation approaches to improve the waterproof and moisture permeability of fiber membranes, among which electrospinning has emerged as the simplest and most effective one. In this paper, poly (vinylidene fluoride) /silica (PVDF/SiO2) fibrous membranes were prepared by one-step electrospinning combined with heat treatment. The morphology, surface wettability, water resistance and moisture permeability of the fibrous membranes were also characterized. When the concentration of PVDF was 12 wt.%, the nanofiber membranes exhibited the most uniform and optimal morphology. In addition, the fiber membranes not only exhibited a high water contact angle (WCA) (135.56 °) and a small maximum pore size (dmax) (1.77 μm), but also demonstrated a large hydrostatic pressure (116.86 kPa) and a moderate water vapor transmission rate (WVTR) (3.53 kg m-2 d-1). The PVDF/SiO2 fibrous membranes with good waterproof and moisture permeability obtained in this work are expected to improve the comfort of protective textiles and expand the application range.

Multi-scale evaluation of surfactant effects on asphalt desorption behavior from oil sand surfaces

This study created a hydrophobic oil sand model to investigate the impact of surfactants on the desorption behavior of asphalt from solid surface. Cationic surfactant cetyl trimethyl ammonium bromide (CTAB) and anionic surfactant sodium dodecyl benzene sulfonate (SDBS) were used to soak the model to observe the effect of surfactants on asphalt desorption. The effect of surfactant pretreatment on the wettability of the substrate was evaluated by measuring the contact angle of ultrapure water on the substrate and observing the morphological changes of the solid surface by atomic force microscopy. The results show that the contact angle of the model treated with SDBS decreases to 10° after 3 days, which significantly improves the wettability of the substrate surface and promotes the desorption of asphalt. However, CTAB has no obvious effect on asphalt desorption. The standard deviation of the gray value of the sand surface image is significantly reduced to 38.693 after the SDBS treatment, which can be seen by binarizing the image. This suggests that the asphalt and solution are evenly distributed and that there is hardly any discernible boundary. Nevertheless, neither of the two surfactants can improve the water-based extraction efficiency of oil sands after soaking treatment. The asphalt yield is less than 5% after 30 days of pretreatment with CTAB solution, while only 45% asphalt yield is obtained after 30 days of pretreatment with SDBS solution. Despite these variations, the quality of asphalt foam remains relatively the same. This may be related to the failure of surfactants to improve the surface wettability of hydrophobic sand. Therefore, the surface wettability of the sand is considered to be a key factor affecting the asphalt desorption and final yield. This study can provide a scientific basis for oil sand recovery to a certain extent.

Characterization and physiochemical of PCL/extracted collagen blend coated nanostructure Sodium-Alginate substrate for skin tissue engineering application

Abstract This study involves fabrication a nano-membrane of collagen and polycarbolactone by electrospinning and depositing into alginate films prepared by casting method to serve as a scaffold for tissue engineering. Collagen extracted from bovine skin showed poor ability to electrospun, so polycaprolactone (PCL), a synthetic polymer commonly used in tissue engineering scaffolds was chosen to improve the electrospinning process and obtain continuous fibers without beads suitable for application in tissue engineering. The scaffolds were analyzed using Field emission scanning electron microscopy, Fourier transformtion infrared spectroscopy, swelling degree testing, and wettability measurements. FESEM results showed that blending PCL with collagen led to improving the electrospinning process and obtaining uniform, continuous fibers (with average fiber diameter 44.97 ± 1.61 nm) without beads and more crosslinking compared to the polycarbolactone scaffold. The results of the wettability and degree of swelling also showed the effect of collagen on increasing the hydrophilicity of the scaffold, and reducedthe water contact angle to (66.66°) with degree of swelling (1256%), that making it suitable for tissue engineering applications.

Dependence of clay–water contact angle on surface charge and ambient temperature: A study from molecular dynamics perspective

The clay-water contact angle emerges as a pivotal parameter essential for elucidating various engineering challenges. Its variability is closely linked to surface charge and ambient temperature, thereby exerting significant influence on soil’s hydraulic properties. However, current research on the joint effects of ambient temperature and surface charge on clay’s contact angle is incomplete, lacking insights from molecular dynamics perspective. Focusing on Young’s contact angle, this study has established diverse montmorillonite-water systems under varying surface charge conditions (cation exchange capacity = 0, 27.60, 54.84, 108.38, and 134.73 meq/100 g) and ambient temperatures (277, 293, 313, 353, 393, and 433 K) through the molecular dynamics (MD) method. The liquid phase boundary is determined by extracting density contour plots and a unified conical curve is introduced to quantitatively analyze the contact angle calculated by MD simulations. This approach led to the development of a nonlinear equation for estimating contact angle variations under different surface charges and ambient temperatures. Finally, the proposed equation is validated against literature data, demonstrating a strong correlation with experimental findings. It exhibits remarkable accuracy in predicting the variations of contact angles induced by ambient temperature under various surface charge conditions. These findings offer valuable insights and practical equation for designing clay impermeable layers in engineering applications.

Formation of hydrophobic membranes by surface spray assisted NIPS: Effects of solvent/non-solvent and spraying conditions

Membrane distillation has long been a potential desalination technology. Recently, spray-assisted non-solvent induced phase inversion (SANIPS) was proposed as a facile and effective method to prepare microporous hydrophobic membranes for membrane distillation. However, the membrane formation process is not fully disclosed. In this paper, SANIPS is employed to fabricate hydrophobic PVDF membranes. The influencing factors on membrane structure and performance are investigated. Membrane structure is greatly affected by the choice of solvent and non-solvent spray. The interactions between different non-solvent sprays (water and ethanol) and solvents (TEP, NMP and DMF) and the effects of operating conditions on membrane formation are explored. Thermodynamic and kinetic analyses of the membrane formation process suggest that the membrane formation process is dominated by the kinetic factors with water being the spray while thermodynamic factors play the major role with ethanol being the spray. A hydrophobic membrane with water contact angle of 135.93 ± 4.38° and LEP of 2.5 ± 0.4 bar was successfully prepared by using ethanol as the non-solvent spray, which demonstrates a stable desalination performance (initial flux of 19.88 ± 1.39 kg·m−2·h−1 and salt rejection higher than 99.97 %) in vacuum membrane distillation. This study may provide pertinent insights into the rational control of membrane structure and performance of hydrophobic PVDF membranes.

Lightweight and hydrophobic silica aerogel/glass fiber composites with hierarchical networks for outstanding thermal and acoustic insulation

Silica aerogels are regarded as potential thermal and acoustic insulation materials with low density and porous structure. However, the hydrophilicity due to surface hydroxyl groups and the low mechanical intensity have limited its further application. Generally, it can be achieved by adjusting the process parameters of the sol-gel to refine the structure of silica aerogels and optimize performance. In this study, we adopted an appropriate modification strategy of incorporating glass fiber felts as the reinforcing phase and trimethylchlorosilane (TMCS) as the hydrophobic modifier. By adjusting the solvent exchange time, the micro-nano structure, i.e. hierarchical networks, was optimized. The TMCS-modified silica aerogel/glass fiber/hot-melt fiber composites (TSGMs) exhibited great sound insulation, and the maximum sound transmission loss (STL) was up to 34 dB at 6300 Hz. Compared to unmodified, STL improved by 8 dB in simulated practical applications. In addition, TSGMs also exhibited high hydrophobicity with a water contact angle of 147° and excellent thermal insulation with a thermal conductivity of 0.0345 W (m k)-1. The results could contribute to the refinement in the preparation process of silica aerogel composites and use in the fields of thermal and acoustic insulation.

Facile development of flexible cellulose acetate-lead dioxide membrane electrodes for supercapacitor applications

Current work focuses on the development of flexible membranes of cellulose acetate containing lead dioxide for supercapacitor applications. The functionality of cellulose acetate and lead dioxide are analyzed by Fourier transform infrared spectroscopy. The degree of crystallinity is studied using X-ray Diffraction. The degree of hydrophilicity is discussed by water contact angle measurements. A Universal Testing Machine is used to examine the mechanical properties. The electrochemical performances are illustrated using Cyclic voltammetry, Electrochemical impedance Spectroscopy and Galvanostatic charge-discharge techniques. The highest recorded specific capacitance is 148 F g−1 at a current density of 40 mA g−1 for a membrane of 1 wt% lead dioxide in cellulose acetate. Capacitance retention of 89% after 5000 cycles is attained. The power density of 56 W kg−1 and energy density of 10 Wh kg−1 is achieved. The cellulose acetate doped with lead dioxide membranes can provide a better electrode material matrix for flexible energy storage.

Transparent composite-structure antifogging coating with mechanical abrasion resistance and environmental durability

Superhydrophilic SiO2 coatings offer unparalleled advantages in terms of antifogging properties. However, they show suboptimal mechanical abrasion resistance and environmental durability, limiting their application. Accordingly, research has focused on the trade-off between hydrophilicity and mechanical abrasion resistance as well as between environmental durability and visible transmittance in superhydrophilic SiO2 coatings. Herein, a composite-structure coating with a densely distributed particulate phase and enhanced crosslinking strength is developed without the use of organic compounds. The coating exhibits remarkable transparency and antifogging properties, with an average transmittance similar to that of bare glass and a water contact angle of approximately 0°. Moreover, the coating exhibits impressive hardness and adhesion of up to 4H and 5B, respectively. The coating retained its antifogging properties even after undergoing 500 cycles of wear induced using a 3000-mesh sandpaper, impact of sand (40 g) dropped from a height of 40 cm, 10 weeks of exposure to the outdoor environment, and 25 h of immersion in water. The test results demonstrate that the coating exhibits satisfactory mechanical abrasion resistance and environmental durability, which are essential for its practical applications. The composite structure formed using linear SiO2 molecules as crosslinking agents with spherical SiO2 nanoparticles considerably enhances the adhesion and abrasion resistance of the coatings. Overall, the developed composite-structure coatings will facilitate their commercial viability and expand the application of superhydrophilic materials in various research fields.

Enhancing degradation of PLA-made rigid biodegradable plastics with non-thermal plasma treatment

This study evaluated the efficacy of Dielectric Barrier Discharge Non-Thermal Plasma (DDBD-NTP) as a pretreatment method to enhance the degradation of rigid biodegradable plastics (RBP) during composting, specifically focusing on polylactic acid (PLA) products such as drinking cups (CS) and spoon handles (SH). Using a Single-Factor-At-A-Time (SFAT) design, the impact of NTP parameters, including input voltage and treatment duration, on the physicochemical properties was evaluated, and the subsequent degradation rate of RBP was assessed by measuring the degree of disintegration in a home-scale composter. The filamentary discharge mode of the DDBD plasma system selectively altered the surface characteristics of RBP without significantly affecting their bulk properties. High-voltage treatments significantly increased surface roughness and accelerated degradation rates, while low-voltage and short-duration treatments enhanced oxidation, as indicated by the increased O/C ratio (85.5% for SH and 66.1% for CS), showing a non-linear response to plasma intensity. Furthermore, NTP treatment reduced water contact angles (up to a 39.79% reduction for SH and 82.65% for CS), indicating enhanced hydrophilicity. All NTP-treated samples demonstrated significantly higher degradation rates compared to both untreated and thermally treated counterparts. Notably, ‘high-voltage for short-duration’ treatments, such as CS-3 and SH-3, exhibited the highest degradation rates among the samples. CS-3 achieved complete disintegration (100%) within 20 days, markedly exceeding the 2% observed in untreated CS samples. Similarly, SH-3 reached 36% disintegration after 35 days, considerably surpassing the 9% seen in untreated SH samples. The findings indicate that NTP treatment is a viable and sustainable method to enhance the biodegradation of plastic waste.