Water Swelling Properties Research Articles

Cotton-like antibacterial polyacrylonitrile nanofiber-reinforced chitosan scaffold: Physicochemical, mechanical, antibacterial, and MC3T3-E1 cell viability study

Bio-scaffolds, while mimicking the morphology of native tissue and demonstrating suitable mechanical strength, enhanced cell adhesion, proliferation, infiltration, and differentiation, are often prone to failure due to microbial infections. As a result, tissue engineers are seeking ideal scaffolds with antibacterial properties. In this study, silver nanoparticles (AgNPs) were integrated into cotton-like polyacrylonitrile nanofibers via a polydopamine (PDA) interlayer (Ag@p-PAN). These Ag@p-PAN nanofibers were then incorporated into the chitosan (CS) matrix, developing an antibacterial CS/Ag@p-PAN composite scaffold. The composite scaffold features an interconnected porous morphology with fiber-infused pore walls, improved water absorption and swelling properties, a controlled degradation profile, enhanced porosity, better mechanical strength, strong antibacterial properties, and excellent MC3T3-E1 cell viability, adhesion, proliferation, and infiltration. This study presents a novel method for reinforcing CS-based scaffolds by incorporating bioactive nanofibers, offering potential applications in tissue engineering and other biomedical fields.

3D printed multi-coupled bioinspired skin-electronic interfaces with enhanced adhesion for monitoring and treatment

Skin-electronic interfaces have broad applications in fields such as diagnostics, therapy, health monitoring, and smart wearables. However, they face various challenges in practical use. For instance, in wet environments, the cohesion of the material may be compromised, and under dynamic conditions, maintaining conformal adhesion becomes difficult, leading to reduced sensitivity and fidelity of electrical signal transmission. The key scientific issue lies in forming a stable and tight mechanical-electronic coupling at the tissue-electronic interface. Here, inspired by octopus sucker structures and snail mucus, we propose a strategy for hydrogel skin-electronic interfaces based on multi-coupled bioinspired adhesion and introduce an ultrasound (US)-mediated interfacial toughness enhancement mechanism. Ultimately, using digital light processing micro-nano additive manufacturing technology (DLP 3D), we have developed a multifunctional, diagnostic-therapeutic integrated patch (PAMS). This patch exhibits moderate water swelling properties, a maximum deformation of up to 460%, high sensitivity (GF = 4.73), and tough and controllable bioadhesion (shear strength increased by 109.29%). Apart from outstanding mechanical and electronic properties, the patch also demonstrates good biocompatibility, anti-bacterial properties, photothermal properties, and resistance to freezing at −20 °C. Experimental results show that this skin-electronic interface can sensitively monitor temperature, motion, and electrocardiogram signals. Utilizing a rat frostbite model, we have demonstrated that this skin-electronic interface can effectively accelerate the wound healing process as a wound patch. This research offers a promising strategy for improving the performance of bioelectronic devices, sensor-based educational reforms and personalized diagnostics and therapeutics in the future. Statement of significanceEstablishing stable and tight mechanical-electronic coupling at the tissue-electronic interface is essential for the diverse applications of bioelectronic devices. This study aims to develop a multifunctional, diagnostic-therapeutic integrated hydrogel skin-electronic interface patch with enhanced interfacial toughness. The patch is based on a multi-coupled bioinspired adhesive-enhanced mechanism, allowing for personalized 3D printing customization. It can be used as a high-performance diagnostic-therapeutic sensor and effectively promote frostbite wound healing. We anticipate that this research will provide new insights for constructing the next generation of multifunctional integrated high-performance bioelectronic interfaces.

Optimizing modified natural rubber in starch-based hydrogels: A cost-effective approach for high-performance sustainable slow-release fertilizer coatings

Effective compatibility between natural rubber (NR) and cassava starch (CSt) is crucial for enhancing the water swelling and retention properties of CSt/NR-based hydrogels. In this study, NR was modified by grafting glycidyl methacrylate (NR-g-GMA, NRG) at 3, 6, and 9 parts per hundred rubber (phr) for blending with CSt. Subsequently, CSt was grafted with acrylamide (AM), crosslinked with N,N′ − methylene-bis-acrylamide (MBA), and interpenetrated with NRG to produce CSt-g-PAM/NRG hydrogels. The resulting CSt-g-PAM/NRGx (x = phr of GMA) hydrogels were characterized using FTIR, XRD, TGA, tensile testing, and water swelling measurements. Results revealed that CSt-g-PAM/NRG3 exhibited the highest equilibrium water swelling at 3300 %, surpassing CSt-g-PAM/NR (1430 %) and demonstrated the highest mechanical strength (0.92 MPa), desirable biodegradability (69 % at 30 days), and good water retention. These properties are attributed to the superior compatibility and stronger interactions between NRG and the CSt-g-PAM networks. Additionally, the WUHNRG3 (urea coated with CSt-g-PAM/NRG3 and wax layers) fertilizer demonstrated good biosafety, an acceptable slow-release rate (50.26 % at 30 days), and effectively promoted the growth of chili plants at a reasonable cost. This study demonstrates that modifying NR with optimal GMA content provides an effective CSt-g-PAM/NRG coating membrane, suitable for sustainable slow-release fertilizers and green agricultural practices.

Influence of high hydrostatic pressure treatment on the soluble dietary fiber content and physicochemical characteristics of edamame

We used non-thermal high hydrostatic pressure (HHP) technology to process edamame to increase the soluble dietary fiber content of the product. We also comprehensively explored the impact of HHP on the functional properties and fiber structure of edamame. Edamame was treated at a high pressure of 600 MPa for 5-, 10-, and 15-min. Edamame treated with HHP exhibited elevated water-holding, oil-holding, and water-swelling capacities, which were attributed to alterations in the fiber structure. Scanning electron microscopy, used to assess the porous characteristics of the surface, revealed gaps that could retain liquid. This structural modification facilitated enhanced invitro performance in cholesterol adsorption and bile acid-binding force tests. X-ray diffraction analysis revealed that the broken fibers strengthened the (101) crystal plane of fiber crystal I; the reduction in crystallinity caused the fibers to form a loose structure under thermal stability, which increased the water retention and swelling properties. HHP destroyed part of the fiber structure, contributing to the altered functional properties. The findings indicate that HHP treatment adds significant value to edamame, making it a promising raw material for developing functional foods and healthcare products.

Effect of acetic acid solutions on regenerated fibers from rennet-treated casein micelles

Fibers made from rennet casein micelles promise a wide range of new applications in food-grade products. Understanding the influence of environmental conditions such as pH on the water binding and swelling properties is a crucial factor for embedding them in hydrated matrices in the future. The expansion of the fibers in dilute acetic acids always takes place in two steps, as previously observed in citric acid. Model analyses showed that the rates of the swelling steps decreased with increasing acetic acid strength. In contrast, the simulated plateau values of both swelling steps increased. Differences to swelling in citric acid are discussed for the second swelling step on the basis of the pH value of the swelling media, while different calcium affinities are assumed for the first swelling step.

Adsorption studies of toxic organic pesticides from aqueous medium by sodium alginate‐cl‐poly (allyl amine‐co‐acrylic acid)/copper oxide nanocomposite hydrogel: Isotherms, kinetics, and thermodynamics

AbstractThe sodium alginate (SAG) cross‐linked poly (allyl amine‐co‐acrylic acid)/copper oxide [SAG‐cl‐poly(AAM‐co‐AA)/CuO] nanocomposite hydrogel (SNCHG) was synthesized by using a free radical initiated cross‐linked copolymerization process in‐situ. Several characterization techniques namely FTIR, PXRD, FESEM with EDAX, TGA, and BET analysis were employed to characterize the synthesized SNCHG. Water swelling properties together with swelling kinetics of SNCHG were evaluated. The highest swelling (35% after 30 minutes) was found at pH 8. The adsorption property of the developed nanocomposite hydrogel (SNCHG) was evaluated in three pesticides' solution namely chlorpyrifos (CP), phosalone (PL), and 4,4'‐ dichloro diphenyl dichloro ethane (DD) in water medium. Several factors affecting the adsorption like solution pH, time of adsorption, amount of pesticides, etc. were evaluated. The maximum adsorption were found to be 96.9% for CP at pH 7, 95.85% for PL at pH 7, and 86.72% for DD at pH 4. Pseudo‐second order kinetics and both Freundlich and Dubinin–Radushkevich adsorption isotherms were followed in all the three cases. Maximum adsorption capacity (Qm) were found to be 507.61, 158.22, and 132.97 mg g−1 for CP, PL, and DD, respectively. The adsorption process was endothermic in nature and spontaneous.Highlights A novel CuO Nps embedded sodium alginate‐based hydrogel is developed. Increment of surface area and water swelling property are illustrated. The hydrogel exhibits excellent adsorption property towards pesticides. The observed affinity of adsorption is chemisorption.

Removal of trisacryl red using hydrogels composites based on chitosan

This study entails the radical copolymerization synthesis of (2-acrylamido-2-methyl-1-propane sulfonic acid) AMPS, utilizing (N,N’methylene bis-acrylamide) MBAm as a cross-linking agent and potassium persulfate (PPS) as an initiator to produce chitosan-based composite hydrogels. The investigation involved the various masses of chitosan (250, 500, and 1000 mg). The characterization of the obtained composites and the dye adsorption process was carried out using FTIR, TGA, SEM, UV-visible, and STEM techniques. Swelling properties in distilled water were examined, revealing that the swelling rates at temperatures of 25°C and 37°C for the hydrogel of poly(AMPS-g-MBAm)/chitosan (1000 mg) exceed those of hydrogels with poly(AMPS-g-MBAm)/chitosan (250 and 500 mg). Furthermore, the sorption capacities of the dye were investigated, demonstrating that the sorption capacities of poly (AMPS-g-MBAm)/chitosan (1000 mg) at different temperatures surpass those of poly(AMPS-g-MBAm)/chitosan (250mg, and 500 mg).

Next Generation Fluorine-Free Proton Exchange Membranes for Electrochemical Energy Applications

Most commercially available proton exchange membrane (PEM)-based fuel cell and electrolyser systems currently employ perfluorinated sulfonic acid (PFSA)-based PEMs, e.g., Nafion. The use of these fluorinated polymers presents serious health and environmental concerns as their production, degradation, and disposal results in the release of hazardous perfluorinted compounds that have been shown to accumulate in the environment and are toxic to living organisms.[1] Developing non-toxic, safe-by-design hydrocarbon PEMs is therefore crucial to ensure that renewable technologies that rely on proton exchange membranes remain an environmentally friendly solution. Additional shortcomings of PFSA-based PEMs include their expensive synthetic cost, inherently high hydrogen crossover, and limited operating temperature range due to poor thermo-mechanical properties above 90 °C. Hydrocarbon (HC)-based membranes offer advantages over their perfluorinated counterparts in these specific areas, however, the main drawback of HC-PEMs is that they require a much greater density of sulfonic acid groups to achieve similar proton conductivities as PFSA-based polymers.[2] This leads to greater water uptake and excessive swelling which ultimately leads to reduced mechanical stability of HC membranes.More recently there has been an increasing number of reports exploring the use of block copolymer strategies to limit the water uptake and swelling properties of hydrocarbon PEMs while maintaining good ionic conductivity.[3] As the ion, liquid, and gas transport properties of the membrane are largely attributed to the hydrophilic blocks (i.e., with sulfonic acid groups) and the mechanical, chemical, and thermal stability of the resulting membrane is determined by the hydrophobic blocks (i.e., no sulfonic acid groups), it is postulated that the resulting membrane properties can be tuned by varying the fraction of hydrophilic/hydrophobic blocks.The overall goal of this project is to synthesise hydrocarbon block copolymer PEMs with reduced gas crossover and enhanced the mechanical properties while maintaining sufficiently high ionic conductivity, ultimately leading to higher performance and greater durability inelectrochemical energy conversion and storage systems, e.g., fuel cells and electrolysers. In this project we have compared the ex-situ properties of novel hydrocarbon block copolymers with PFSA-based Nafion membranes, e.g., water uptake and swelling, conductivity measurements, oxidative stability via Fenton's test, etc., as well as in-situ performance tests in single cell fuel cell and electroylzers.[1]Feng, M.; Wang, Z. et al. Sci. Rep. 2015, 5, 9859.[2]Holdcroft, S. Chem. Mater. 2014, 26, 381.[3]Guiver, M. et al. Chem. Rev. 2017, 117, 4759.

Wet refining: A novel approach for modification of wheat bran fiber

To address the poor physiochemical and functional properties a novel wet refining (using Valley Beater) treatment was adopted for modification of wheat bran fiber. Valley Beater, which is valuable equipment in the pulp and paper industry to improve fiber properties, was optimized for wheat bran using response surface methodology. The obtained modified bran fiber was further compared, separately and in combination with the moist heat modified wheat bran. The effect of modifications was accessed in terms of physiochemical, functional, morphological, structural, and antioxidant properties. Particle size, SEM, FT-IR spectroscopy, and XRD analysis depicted the successful modification effects with a good explanation of different improved properties. The wet refining process significantly improved the bran fiber water absorption, oil absorption, water swelling, and sedimentation properties along with increasing the fines content. Although, the moist heat modification showed a positive effect on soluble dietary fiber, and glucose absorption capacity. Still, the wet refining modification was found to ameliorate bran fiber antioxidant properties such as total phenolic content, DPPH scavenging capacity, and total reducing power. Categorically, the combined (wet refining followed by moist heating) modification process was most suitable with more desirable effects. Our research manifested that the wet refining process in combination with moist heat treatment can be used to improve nutritional and product-making characteristics of wheat bran fiber and thus can be adopted for preparing high-fiber food products.

Multifunctional starch-based double-network hydrogels as electronic skin

The realization of flexible pressure sensors that could mimic the perception functions of human skin (touch, temperature, and humidity) is important for development of electronic skin. However, the design and preparation of highly sensitive sensors for multifunctional sensing of pressure, temperature and humidity remains a challenge. Here, we first designed and prepared a flexible starch/polyacrylamide (PAM) double-network hydrogel, with additional introduction of Na+ and Cl− to further enhance the electrical properties. Subsequently, a multifunctional pressure sensor was fabricated by sandwiching a microstructured starch-based hydrogel into two flexible AgNWs electrodes. In the test run, the prepared sensor exhibited a high sensitivity of 48.35 kPa−1, a fast response time of 11 ms, and remarkable mechanical stability (>3000 cycles). Given the satisfactory performance for pressure sensing, we demonstrated the ability of the sensor to monitor various human dynamics. Moreover, the starch-based hydrogel was further developed as a flexible temperature and humidity sensor for its water absorption and swelling properties. In particular, the asynchrony of pressure, temperature and humidity strains (straining to stability at 11 ms, 2 s and 10 s, respectively) resulted in the automatic separation of different electrical signals. The intuitive interpretation of the data without involving complex parameter separation calculations allowed the starch-based hydrogels to be developed as an integrated, multifunctional sensor of pressure, temperature and humidity with high sensitivity and flexibility. The above properties suggest that the prepared bio-based hydrogels may provide a new solution for the prospect of green and multifunctional electronic skin development.

The justification of the optimal composition and research of a local hemostatic agent based on naturally occurring polysaccharides

The analysis of existing methods and products for controlling bleeding reveals that medical means exhibit significantly higher efficacy compared to mechanical methods of achieving hemostasis. However, it is important to note that medical means cannot entirely replace surgical hemostasis in cases of severe bleeding from large veins and arteries. In emergency situations, such as during military conflicts or workplace injuries, the use of local contact hemostatic agents is preferred. These agents do not require specialized skills for application, making them accessible to individuals in need of immediate assistance. If included in a first-aid kit, these agents enable victims to address minor injuries promptly and control bleeding. In critical bleeding situations, any nearby individual can use the tool to provide aid. Given the ongoing military activities within our country’s territory, the development of effective domestic hemostatic agents has become an urgent priority. This initiative aims to ensure the availability of such products to our military personnel. Aim. The aim of this work is to justify the optimal composition of a local hemostatic agent based on readily available raw materials and feasible technologies. Materials and methods. After conducting an extensive review of domestic and foreign literature, the basis for the development of the future contact hemostatic agent was chosen to be adsorbing materials derived from biologically active components of mineral, synthetic, phyto-, and organic origins. The focus of this study is on natural polysaccharides with potential hemostatic activity, specifically alginate, kappa carrageenan, guar gum, and xanthan gum. One key property of polysaccharides is their ability to swell, which positively influences hemostasis. The hemostatic effect of model hemostatic compositions was evaluated using a femoral artery bleeding model induced by mechanical damage. Additionally, a model involving capillary-parenchymal bleeding from a laceration wound on the liver in adult rats was employed for further investigation. Results. Experimental studies have provided evidence of the hemostatic effect of natural polysaccharides due to their water absorption and swelling properties. In comparison with well-known medical products Celox and Revul®, substances with hemostatic activity, including alginate, kappa carrageenan GU 805, and the comparative drug Celox, have demonstrated significant reductions in bleeding time. Specifically, alginate, kappa carrageenan GU 805, and Celox have shown reductions of 38 %, 53 %, and 57 % respectively, compared to the positive control (PC) group. To enhance the hemostatic activity, a combination of the leading compounds with the addition of 7 % calcium gluconate was developed. The inclusion of calcium gluconate in the combination is associated with the involvement of calcium ions in all stages of blood coagulation, thereby increasing the overall hemostatic effect of the combination. Based on the obtained results, it can be concluded that substances with hemostatic activity, such as alginate, kappa carrageenan GU 805 in combination with calcium gluconate, miramistin, and a mixture of phytocomponents, as well as the comparative drugs Celox and Revul®, reliably reduce bleeding time by 46 %, 47 %, 37 %, and 36 %, respectively, in comparison to the PC group. Conclusions. The optimal composition of a contact hemostatic agent, formulated as a multicomponent powder known as Plantor, has been developed. This composition is based on natural saccharides and incorporates a complex of antiseptic and wound-healing substances derived from natural and synthetic sources. The formulation of Plantor demonstrates optimal consistency, biopharmaceutical properties, and pharmacotechnological characteristics. The addition of 7 % calcium gluconate to the composition was found to effectively enhance the level of hemostatic activity. This enhancement is attributed to the involvement of calcium ions in all stages of blood coagulation. Experimental studies conducted using a hemostatic model have confirmed that the proposed composition of the pharmacotherapeutic agent significantly reduces bleeding time by 47 % and accelerates the overall process of hemostasis. The observed efficacy of the Plantor formulation surpasses that of reference local hemostatic agents, indicating its superior effectiveness in promoting hemostasis.

Biodegradable Zein-Based Biocomposite Films for Underwater Delivery of Curcumin Reduce Thermal Stress Effects in Corals.

Massive coral bleaching episodes induced by thermal stress are one of the first causes of coral death worldwide. Overproduction of reactive oxygen species (ROS) has been identified as one of the potential causes of symbiosis breakdown between polyps and algae in corals during extreme heat wave events. Here, we propose a new strategy for mitigating heat effects by delivering underwater an antioxidant to the corals. We fabricated zein/polyvinylpyrrolidone (PVP)-based biocomposite films laden with the strong and natural antioxidant curcumin as an advanced coral bleaching remediation tool. Biocomposites' mechanical, water contact angle (WCA), swelling, and release properties can be tuned thanks to different supramolecular rearrangements that occur by varying the zein/PVP weight ratio. Following immersion in seawater, the biocomposites became soft hydrogels that did not affect the coral's health in the short (24 h) and long periods (15 days). Laboratory bleaching experiments at 29 and 33 °C showed that coral colonies of Stylophora pistillata coated with the biocomposites had ameliorated conditions in terms of morphological aspects, chlorophyll content, and enzymatic activity compared to untreated colonies and did not bleach. Finally, biochemical oxygen demand (BOD) confirmed the full biodegradability of the biocomposites, showing a low potential environmental impact in the case of open-field application. These insights may pave the way for new frontiers in mitigating extreme coral bleaching events by combining natural antioxidants and biocomposites.

Blend of Multi-Walled Carbon Nanotubes and Quercetin Improves Physicochemical Properties of Chitosan Membrane for Wound Dressing Application

Although wound dressings are essential to protect wound from infection, these wound care products have limited function in facilitating wound healing. This study aimed to synthesize multi-walled carbon nanotube (MWCNT)/quercetin (QUE)/chitosan (CS) blended composite membrane and analyze their physicochemical properties for wound dressing application in comparison to the pure chitosan (CS) membrane. The MWCNT/QUE/CS blended membranes were prepared by mixing CS, QUE and MWCNT at a ratio of 3:1:1 using a solvent casting method. The membranes were analyzed physicochemically for their surface morphology, elemental composition, structural composition, wettability, water vapor transmission rate (WVTR) and swelling properties and were compared to the pure CS membrane. The findings pointed out that the blend of MWCNTs and QUE in the CS matrix produces a membrane with uneven and more hydrophilic surface with water contact angle of 64.70°± 3.7 and low WVTR of 16.26 g/m2.day after 24 h. The swelling analysis showed that the blended membrane was able to absorb more than 60% of water within 10 minutes, although lower than the pure CS membrane. This study revealed that MWCNT/QUE/CS blended membrane could possibly be used as a wound dressing as it may promote moist environment needed for wound healing in addition to its antibacterial and antioxidant properties that may accelerate wound healing process.

Radiation Synthesis of Edible Coating Films of Nanocurcumin Based on Carboxymethyl Chitosan/Polyvinyl Alcohol to Extend the Shelf Life of Sweet Orange "Valencia"

AbstractEdible coating CMCS/PVA/Cur and films were prepared using γ-irradiation to extend the shelf-life of sweet orange "Valencia" fruits. Water-soluble CMCS was synthesized by carboxymethylation of chitosan. Extraction of curcumin from turmeric powder and conversion to Cur-NPs of 76–108 nm average size was achieved. CMCS/PVA/Cur membranes were prepared via the casting method and gamma-irradiation technique. The chemical properties were studied by FTIR and XRD as well as studying the effect of irradiation dose on gel content, water swelling, and mechanical properties. FTIR and XRD results confirm the interaction between functional groups of Cur-NPs with CMCS/PVA polymer chains. Results indicated that the membrane possessed good tensile strength and gel content of 97.4% and the swelling was significantly decreased with increasing the irradiation dose. Fruits were dipped in CMCS/PVA/Cur coatings at different concentrations of Cur-NPs (0, 2.5, 5, and 10%) and stored at room temperature of 65–70% RH for about 70 days. The efficiency of coatings was assessed by decay (%), weight loss (%), pH, vitamin C content, total soluble solids (TSS), titratable acidity (TA), and TSS/TA ratio. Quality characteristics of coated fruits were better than uncoated fruits especially the coating solution of 2.5% Cur-NPs provides accepted freshness and quality. No decay was noticed for the coated fruits till 56 days, whereas the control exhibited decay of 36%. The prepared coating solutions possessed good antimicrobial activity and cytocompatibility characteristics and showed normal viability even at all concentrations. Results demonstrated a promising packaging material to extend the shelf life and freshness of orange fruits.

Structural control of PEG-intercalating Na-bentonite and its influence on the properties of castor oil-based polyurethane coating

Although controlled-release fertilizer (CRF) is a safer and more efficient strategy to administer nutrients for plant growth, it is still a daunting task to reduce the cost and improve the degradability of the synthetic resin coatings. In this paper, an inorganic/organic composite coating for urea fertilizer was prepared from a biodegradable castor oil-based polyurethane (PU) filled with the layered Na-bentonite (Na-BT), which was ultrasonically treated by a series of green PEG surfactants. Synergistically influenced by various intercalation ability, cation-hosting ability and hydrophilicity of the PEGs, the porous structures of the modified Na-BT (MBT) fillers were simply tuned by varying the Mn molecular weights of the PEGs, resulting in the adjustable water swelling and mechanical properties of the MBT/PU composites. Moreover, it was confirmed that the water swelling property played a critical role in controlling the early stage of nutrient release, and the mechanical properties were important for the longevity of nutrient release from the CRFs. The best MBT/PU composite supported a CRF with a long-term release of 75 % in 38 days, which was much longer than the one based on pure PU (20 days).

Preparation and Characterization of Black Pomegranate Peel Extract-Loaded Nanofibers Using Electrospinning

Background: Blended electrospun nanofibrous mats containing black pomegranate peel extract (BPPE) were prepared using different proportions of polyvinylpyrrolidone (PVP) and polycaprolactone as the filament-forming polymers. Methods: The electrospinning process was conducted by simultaneously injecting PVP and polycaprolactone spinning solutions from two opposite sides on a rotary collector. The films were characterized in morphology, mechanical features, water vapor transmission rate, swelling properties, and drug release profile. Results: The uniform white porous nanofibrous mats were achieved using the optimized method. As the concentration of PVP in the formula increased, the average diameter of the fibers increased, and fibers containing spindle bodies appeared. Though, the moisture content is one of the most essential issues with a wound dressing to promote the healing process, excessive water absorption by PVP produced highly erodible mats with weak tensile strength and elongation. The higher content of polycaprolactone created narrower and more uniform fibers and improved the mechanical features and water swelling properties of the blended mats. Furthermore, the nanofibrous membrane composed of a 70:30 polycaprolactone/PVP weight ratio resulted in a more sustained drug release. Conclusion: The favorable properties mentioned above, along with the wound healing effect of BPPE, make it an attractive candidate for application in wound dressing products.

Seawater-triggered self-renewable amphiphilic coatings with low water swelling and excellent biofilm prevention properties

Amphiphilic antifouling coatings have the potential to revolutionize the field of eco-friendly antifouling coatings, which are still beset by the drawbacks of instability, complex procedures and water swelling. Herein, we construct seawater-triggered amphiphilic coatings with self-renewable capabilities in seawater via the facile casting of a physical mixture of a hydrolyzable polymer (PTMH), hydroxyl-terminated polydimethoxysilane and an isocyanate crosslinker. The hydrophilic chain is generated in situ from PTMH at the coating/seawater interface and thus ultimately mitigates its seawater swelling. The hydrolyzability of PTMH and the degradation of the urethane crosslinking bond endow the coating with self-renewable properties. Owing to the appropriate hydrolysis rate of PTMH, its water absorption is lower than 3 wt% for 30 days of seawater submersion. Notably, the biofilm prevention capability of the coatings is excellent, outperforming that of polydimethoxysilane-based polyurethane and self-polishing polymers in real sea conditions. We envision that this work will provide a new avenue to design microphase separation-based antifouling coatings for practical applications.

Fenton-like redox-initiated synthesis of superabsorbent composites with excellent water retention and swelling properties based on green tea and oil shale semi-coke

Much increasing attention recently has been paid for the design of superabsorbent composites with superior adsorption/retention performances by economic and efficient preparation process. Herein, a facile and economic preparation strategy were employed for preparation of high-performance superabsorbent composites based on the redox-reaction between the components derived from natural green tea (GT) and calcined oil shale semi-coke (COSSC). The as-prepared chitosan-grafting-polyacrylic acid/green tea/calcined oil semi-coke (CS-g-PAA/GT/COSSC) superabsorbent composites showed the favorable water absorption capability and water uptake rate of 404 g/g in distilled water and 62 g/g in 0.9 wt% NaCl solution in 30 mins. After being buried for 90 days in soil, the superabsorbent composites indicated a 57 % biodegradation rate due to the presence of natural polymer of CS and GT residues. The superabsorbent composites also exhibited the perfect water retention capacity in soil, the total seed biomass and stem length of cabbage increased by 27.20 % and 30 %, after incorporation of 0.5 % of superabsorbent composites in soil, respectively. Based on the excellent water absorption, water retention and growth-promoting properties, the high efficient and economic superabsorbent composites prepared via low temperature-initiated polymerization presented a great potential in the charge of arid and semi-arid agriculture.

Preparation of a novel biodegradable film by co-fermentation of straw and shrimp shell with Aureobasidium pullulans and Photobacterium sp. LYM-1

The green and high-value recycling of shrimp shell and straw remains a worldwide problem. This study aimed to investigate the potential utilization of a fermentation broth (FB) which contains shrimp shell and straw as a new source for preparation of biodegradable films. Aureobasidium pullulans and Photobacterium sp. LYM-1 were used in the fermentation. The cellulase activity was 115.92 U/mL and chitinase activity was 17.89 U/mL in FB. The polysaccharides concentration in FB was 1.05 mg/mL after 7 days of fermentation. An eco-friendly PVA-reinforced FB biodegradable film (FBBF) was successfully prepared and the effect of different plasticizers and surfactants on the mechanical, structural, and impermeability properties of the film was determined. The formation of new bonds between PVA and FB was proved by FTIR spectroscopy. The FBBF containing 0.25 % (w/v) glycerol and 0.01 % (v/v) tween-20 showed better strength properties. Elongation and water-swelling properties were highly improved by adding 0.2 % (m/v) citric acid. According to FE-SEM images, the smooth and tight surface of citric acid added FBBF was observed. Interestingly, the FBBF film showed good heat/moisture capacity, antifungal, and degradation properties. This report reveals a new green, and high-value recycling of straw and shrimp shell by the co-fermentation with A. pullulans and Photobacterium sp. LYM-1. It is also a novel way for the preparation of biodegradable film.

Eco‐friendly superabsorbent hydrogels based on starch, gellan gum, citric acid, and nanoclays for soil humidity control

AbstractThe increase in agricultural product demand has entangled the modernization of agriculture. Advances in research have improved production systems, machinery, fertilizers, and pesticides, among others, which are usually applied in an unsustainable way. In this context, hydrogels are attractive materials. Generally, they can be defined as three‐dimensional structures formed from crosslinked hydrophilic polymers with high water absorption capacity. The crosslinks of polymeric chains maintain their structure, letting them absorb large amounts of water without dissolving. This work presents new eco‐friendly superabsorbent hydrogels composed of starch and gellan gum crosslinked with citric acid (CA) and incorporating bentonite (BET) and halloysite (HAL) nanoclays. The addition of nanoclays aimed at developing better soil conditioners, while controlling water management for crop production. Hydrogels with compositions ranging from 100%, 75%, 25%, and 0% of gellan gum to starch, all crosslinked with 10%, 5%, and 2% (w/w) of CA. The samples were characterized by Fourier‐transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC). The water swelling properties were studied.