Uniform Network Structure Research Articles

Three-dimensional hierarchical porous carbon surface-decorated graphitic carbon foam/stearic acid composite as high-performance shape-stabilized phase change material with desirable photothermal conversion efficiency

To simultaneously improve the photothermal conversion and encapsulation capacity of phase change material (PCM), a three-dimensional hierarchical porous carbon surface-decorated graphitic carbon foam (SGF) was developed. Employing this SGF as an encapsulated skeleton for stearic acid (SA), a unique shape-stabilized SA/SGF composite PCM was successfully prepared after vacuum impregnation. The porous carbon surface exhibits a uniform and fluffy three-dimensional continuous network structure well adhered onto the pore walls of the SGF; it can act as a desirable interfacial layer between SA and the SGF, which gives the composite effective encapsulation performance and good interfacial compatibility. The as-prepared composite has a loading capacity of 78.16% for melted SA without any leakage, and possesses a thermal conductivity of 3.25 W/mK with 1377% higher than that of SA and a compressive strength of 4.41 MPa (increasing 283.5% than the SGF). Further, the melting and crystallization enthalpy of the composite reaches 167.6 J/g and 167.5 J/g, respectively, with a thermal storage efficiency of up to 95.13%; meanwhile, it displays excellent thermal cycle stability revealed by keeping an enthalpy of 92.80% after 200 thermal cycles. More importantly, it presents a high photothermal conversion of 90.14% at 200 mW/cm2 with the ability to serve as a stable heat source during solar-thermal-electric conversion. Consequently, the composite has great potential in solar storage and waste heat recycle.

Effects of direct addition of curdlan on the gelling characteristics of thermally induced soy protein isolate gels

In this study, the effects of the direct addition of curdlan on the physicochemical, structural, and functional properties of heat-induced soy protein isolate (SPI) gels were evaluated. Results demonstrated that the direct incorporation of curdlan enhanced the gel-forming performance, water-holding capacity, and gel strength of heat-induced SPI gels. The presence of curdlan reduced the free water molecules and α-helix content in the SPI structure and contributed to the construction of stable SPI gels with uniform and compact network structures, as visually proven by microstructure observations. Moreover, compared with the SPI gel alone, the curdlan–SPI composite gels presented a more pronounced viscoelastic property and thermal stability mainly due to the intermolecular hydrogen bonding interaction between curdlan and the SPI molecules. Our findings suggest that the direct incorporation of curdlan can effectively ameliorate the gelling characteristics of heat-induced SPI gels, indicating its potential application as a promising gel improver in the food industry.

Formation and microstructural characterization of scallop (Patinopecten yessoensis) male gonad hydrolysates/sodium alginate coacervations as a function of pH

Studying the noncovalent interactions between proteins and polysaccharides is quite important mainly due to the wide number of applications such as developing pH-responsive complexes. Scallop Patinopecten yessoensis male gonad hydrolysates‑sodium alginate (SMGHs-SA) was investigated as noncovalent complexes at pH from 1 to 10. The critical pH values pHC (around 6) and pHφ (around 4) were independent of the SMGHs-SA ratio, indicating the formation of soluble and insoluble complexes. The pH response of SMGHs-SA complexes was evaluated by investigating the rheological behavior, moisture distribution, functional group change and microstructure. Compared to the co-soluble and soluble complexes phases, the SMGHs-SA complexes had a higher storage modulus and viscosity as well as a lower relaxation time (T23) in the insoluble complexes phase (pHφ>3). Additionally, the amide I band and COO− stretching vibration peaks were redshifted and the amide A band vibration peaks were blueshifted by acidification. Electrostatic interactions and intermolecular/intramolecular hydrogen bonding led to SMGHs-SA agglomeration at pH 3, forming a uniform and dense gel network structure with strong gel strength and water-retention capacity. This study provides a theoretical and methodological basis for the design of novel pH-responsive complexes by studying SMGHs-SA complex coacervation.

Lithiated Phosphoryl Cellulose Nanocrystals Enhance Cycling Stability and Safety of Quasi-Solid-State Lithium Metal Batteries.

Cycling stability and safety are two of the main challenges facing lithium metal batteries with metallic lithium as anodes. Quasi-solid-state lithium metal batteries based on gel polymer electrolytes are one of the important development directions for lithium metal batteries addressing those challenges. Herein, we prepare lithiated phosphoryl cellulose nanocrystals (PCNC-Li) as a modification material for poly(vinylidene fluoride) (PVDF) gel polymer electrolyte to improve cycling stability and safety of quasi-solid-state lithium metal batteries. The synthesized PCNC-Li tends to form a uniform network structure on the surface of the PVDF membrane, in which the phosphoryl groups grafted regularly on celluloses can regulate the transport of lithium ions. As a result, a more uniform ion flux and more stable lithium anode interface support an obviously improved cycling stability for lithium metal batteries. Moreover, the introduction of the PCNC-Li coating layer makes the modified PVDF membranes have a better thermal stability and an enhanced mechanical strength, which is beneficial for improvement of safety of lithium metal batteries. This work provides a new alternative to fabricating a better composite gel polymer electrolyte for lithium metal batteries.

Effects of carboxymethyl chitosan on the gelling properties, microstructure, and molecular forces of Pleurotus eryngii protein gels

Protein-polysaccharide interactions play a crucial role in development of plant-based food products. This study aimed to investigate the effects of different carboxymethyl chitosan (CMCS) concentrations (0–5.0%) on the gelation, structural properties, molecular interactions, and microstructure of the Pleurotus eryngii protein (PEP) gels. The results showed that the addition of CMCS could improve the rheological, textural properties and water holding capacity of the PEP/CMCS composite gels. Fluorescence spectra, fourier transform infrared spectrum and chemical interaction forces analysis suggested that the formation of the CMCS/PEP complex occurred by static quenching mechanism. The addition of CMCS changed the secondary structure and molecular conformation of the protein, also significantly enhanced the hydrophobic interaction and disulfide bonds of PEP molecules, thus increased the gel properties of PEP. Scanning electron microscopy revealed a denser and uniform network structure with small pores in the CMCS/PEP composite gels. Overall, these results provided an important basis for CMCS to improve the heat-induced gel properties of PEP, and also provided information on the potential use of composite gel as meat analogs in the food processing industry.

Evaluation of feasibility of Tenebrio molitor larval fractions as a meat analog using 3D printing

To confirm the applicability of Tenebrio molitor larvae as meat analogs using three-dimensional printing, the deformation rate after 3D printing and texture profile analysis (TPA) after post-processing (steaming) of 3D printing inks composed of 18% soy protein isolate (SPI) and T. molitor larval fractions (filtrate, supernatant, and pellet) were evaluated. When 15% pellet was included, the lowest deformation was 0.04% due to the structural support and easy extrusion due to the increase of the storage modulus (G'), loss modulus (G"), and loss tangent (tan δ) and uniform network structure. In addition, the sample containing 15% pellets had the highest hardness (83.57 N) and chewability (55.97 N) after post-processing due to the high protein content in the pellets and the presence of myofibrillar proteins and dense internal structure. This study provides guidelines for improving the printability and texture effects through the supplementation of SPI-based inks with T. molitor larval fractions.

Enhancing the Electrical Conductivity and Strength of PET by Single-Wall Carbon Nanotube Film Coating.

Single-wall carbon nanotubes (SWCNTs) with excellent physicochemical properties are considered a promising candidate for the electrical and mechanical reinforcements of polymers. However, the poor dispersion of SWCNTs in plastics seriously limits their application and their achieved performance enhancement. Here, we coat a freestanding, highly conductive SWCNT film onto the surface of a polyethylene terephthalate (PET) film by a hot-pressing method. Due to the uniform SWCNT network structure and strong interfacial interaction, the SWCNT/PET hybrid film showed notably enhanced electrical and mechanical properties even though with a very low SWCNT weight fraction of 0.066%. The surface square resistance of the SWCNT/PET film decreased to 120-140 Ω/□ from 1016 Ω. In addition, Young's modulus and tensile strength of the SWCNT/PET film reached 4.6 GPa and 148 MPa, which are 31.3 and 24.4%, respectively, higher than the pure PET film. The SWCNT/PET film shows excellent mechanical durability and thermal stability, demonstrating its potential use as an antistatic material.

Physicochemical properties and microstructure of soybean protein isolate-vegetable oil complex gels induced by lactic acid bacteria: Effects of vegetable oil types and concentrations

In this work, the physicochemical characteristics and microstructure of soybean protein isolate-vegetable oil complex gel induced by lactic acid bacteria (LSOG) were studied in relation to various kinds (soybean oil, peanut oil, and corn oil) and concentrations (3%-15%) of vegetable oil. The results showed that LSOG with increased hardness, water holding capacity and storage modulus were successfully obtained by adding vegetable oil, especially soybean oil (followed by peanut oil and corn oil), due to a more uniform and denser network structure was formed, thus allowing more water molecules to bind inside the gel. A 12% soybean oil concentration led to LSOG with the highest hardness (87.52 ± 0.75 g), due to strong hydrophobic interactions and disulfide bonds. The presence of soybean oil as a filler affected the binding between protein molecules, thus forming the more stable gel structure, also proved by the increased thermal stability. This study might offer theoretical backing for theories about how oil in the soybean protein gel induced by lactic acid bacteria interacted with soybean protein.

Analysis of pectin-cellulose interaction in cell wall of lotus rhizome with assistance of ball-milling and galactosidase

The current study sought to depict the structural feature of polysaccharides extracted from Na2CO3 unextractable fraction (LUN) of lotus rhizome using galactosidase with assistance of ball milling. The extracted polysaccharides were a complex of cellulose microfibrils and the RG-I structural domain of pectin, and the top three monosaccharides were glucose, galactose and galactose uronic acid, which allowed to tune the properties of the enzyme-hydrolyzed polysaccharide from LUN after 15 and 45 min of ball milling. The data of XRD revealed that pectin has a masking effect on the diffraction peaks of cellulose components. The removing of the polysaccharides could increase the degree of crystallinity and the pectin-cellulose interaction mainly occured through the galactan side chain was speculated. Textural characterization by SEM exhibited a cross-linked rod-like structure, which is similar to the structure of cellulose microfibrils. The morphological analysis of AFM revealed that L15-P (enzyme-hydrolyzed polysaccharide from LUN after 15 min of ball milling) contained relatively ordered and uniform network structures. Overall, the present study provides an important insight into cell wall of lotus rhizome matrix polysaccharide.

Flexible and Transparent Bagasse Aerogels for Thermal Regulation Glazing

The preparation of functional composite aerogels for building envelopes, especially for building glazing as the key climate moderator, has been widely investigated to improve the sustainability of buildings. Unfortunately, the prohibitive costs, mechanical brittleness, and optical opacity limit the current development and application of composite aerogels. Herein, using the controllable extraction of cellulose from bagasse, a low-cost (less than $3 per square foot), flexible (>15% elastic deformation under 0.02 MPa) bagasse aerogel film with high visible-light transparency (>80% transmittance of visible light) and superinsulation (0.0158 W m–1 K–1) was developed. These properties were achieved by constructing a uniform three-dimensional network structure using elastic polysiloxane and a mixture of cellulose nanofibers and cellulose nanocrystals in an equal proportion. This cellulosic aerogel film would have the latent potential of application in highly glazed modern buildings to reduce the energy loss from windows.

Effects of natural inulin on the rheological, physicochemical and structural properties of frozen dough during frozen storage and its mechanism

The impact of various substitution levels of natural inulin on the rheological, physicochemical and structural properties of frozen dough was evaluated in this study. Natural inulin increased the G′ and G″ of samples. Natural inulin dough displayed characteristics with increasing the stability of the protein structure, enhancing the interaction of tightly bound water with protein and starch polymers, and more uniform gluten network structure. The freezing and frozen storage processes can lead to dough quality deterioration. Natural inulin could alleviate damage of long-term frozen storage to dough quality, protecting the protein and gluten network structure, reducing the loss of tightly bound water to degree. Generally, various substitution levels of natural inulin had a positive effect on the rheological, physicochemical and structural properties of dough. The 5 g/100 g natural inulin could better alleviate the quality deterioration of frozen dough during frozen storage and improve the quality of frozen dough.

Preparation of desirable plant protein-based adhesive via bioinspired Laponite-assisted organic-inorganic copolymerization

The preparation of plant protein-based adhesives is one of the potential strategies to mitigate environmental pollution. In this work, the organic-inorganic copolymerization of calcium phosphate oligomer and soy protein was performed by adopting the concept of organic-inorganic polymerization and the physics of polymer adsorption to eliminate the interphase boundary, preparing an adhesive layer with continuous and uniform network structure without using chemical cross-linkers. The participation of ionic and hydrogen bonds improved the mechanical strength. In addition, the Laponite with anisotropic charge distribution was introduced into the cross-linking network to increase the density and cohesion of cross-linking and further improve the bonding performance without complex chemical synthesis. The modified adhesive had an optimum wet shear strength of 1.01 MPa, and excellent water resistance (85.7 % residue rate). The modified adhesive shows good cell compatibility plus flame retardancy. Overall, this biomimetic study has excellent promises for the design of protein-based adhesives with desirable properties for engineering applications.

Carrageenan addition improves the melting temperature and 3D printing performance of the gelatin system

The sturgeon fish skin gelatin (FG) could not form gelation for printing at room temperature and must be hold its shape at low temperature after printing due to low melting and solidifying temperature, causing certain energy loss. The purpose of this study was to investigate the effects of various types (κ-carrageenan: KG; λ-carrageenan: LG; ι-carrageenan: IG) and proportions of carrageenan on the gelation properties and melting temperatures of sturgeon skin gelatin blended system and realize 3D printability at room temperature. The results showed that the turbidity of the blended systems increased significantly with adding 0.4%–0.8% carrageenan. Meanwhile, when the additive concentration of KG was 0.4%, the highest gel strength was 104.02 g. And the hardness and adhesive of gel were 5.44 times and 5.37 times of that single gelatin sample when the concentration of KG reached 0.8%. When IG was added, the melting temperature of the blended system could be improved most obviously, followed by KG, while LG could improve least. In addition, the blended system with IG could form a more dense and uniform network structure. The results of thixotropy showed the gel formed by the blended system had certain thixotropy, but the lag circle area is small resulted in the insufficient shape stability after printing. Among them, the blended systems with 0.8% KG and IG received successfully 3D printing at room temperature.In short, carrageenan has a positive effect on improving the gelation properties and applying in 3D printing of the sturgeon skin gelatin system at room temperature.

Effects of CaCl2 on 3D Printing Quality of Low-Salt Surimi Gel.

In order to develop low-salt and healthy surimi products, we limited the amount of NaCl to 0.5 g/100 g in this work and studied the effect of CaCl2 (0, 0.5, 1.0, 1.5, and 2.0 g/100 g) on the 3D printing quality of low-salt surimi gel. The results of rheology and the 3D printing showed that the surimi gel with 1.5 g/100 g of CaCl2 added could squeeze smoothly from the nozzle and had good self-support and stability. The results of the chemical structure, chemical interaction, water distribution, and microstructure showed that adding 1.5 g/100 g of CaCl2 could enhance the water-holding capacity and mechanical strength (the gel strength, hardness, springiness, etc.) by forming an orderly and uniform three-dimensional network structure, which limited the mobility of the water and promoted the formation of hydrogen bonds. In this study, we successfully replaced part of the salt in surimi with CaCl2 and obtained a low-salt 3D product with good printing performance and sensory properties, which could provide theoretical support for the development of healthy and nutritious surimi products.

The effects of modified quinoa protein emulsion as fat substitutes in frankfurters

In the current study, the effects of replacing different proportions of pork back fat (0, 25, 50, 75, and 100%) with high-pressure homogenization-modified quinoa protein emulsions (HMQE) on the physicochemical, water distribution, and rheological properties of low-fat frankfurters were investigated. HMQE incorporation significantly increased the moisture, ash, protein content, pH and L⁎ values and decreased the a⁎ and b⁎ values and T2 relaxation time of the low-fat frankfurters (P < 0.05). Of note, 50% fat substitution by HMQE yielded higher WHC, textural properties, gel strength, immobilized water percentage and G′ value of the frankfurters than others. HMQE incorporation changed the protein secondary structure from α-helix to β-sheet, forming a compact and uniform gel network structure with small cavities. Moreover, 50% fat substitution by HMQE did not affect sensory characteristics and improved the fat oxidative stability during storage. Therefore, the incorporation of HQME as a partial fat substitute resulted in nutritional benefits and quality enhancements, indicating that HQME could serve as a promising fat alternative in manufacturing low-fat frankfurters with desirable attributes.

The improvement and mechanism of gelation properties of mung bean protein treated by ultrasound

This work aimed to investigate effects of ultrasound treatment on structure and gelation properties of mung bean protein gel (MBPG). Structure properties were evaluated by surface hydrophobicity, free sulfhydryl group, SDS-PAGE, FTIR, intermolecular forces and SEM. And the gelation properties were characterized by rheological properties, textural properties and water holding capacity (WHC). Ultrasound treatment increased surface hydrophobicity and free sulfhydryl group of mung bean protein solution. SDS-PAGE showed that MBPG contained eleven protein bands, with the highest content of 48.8 kDa, and ultrasound treatment did not change the protein profiles of MBPG. Ultrasound treatment decreased α-helix and β-turn of MBPG, while increased β-sheet content. Solubility differences of MBPG in five solvents further demonstrated that ultrasound treatment enhanced hydrophobic interactions and disulfide bonds of MBPG, which were the main forces forming gel. SEM images manifested that ultrasound-treated MBPG had a denser and more uniform network structure than the control, especially at 300 W ultrasound treatment. MBPG treated with 300 W had the largest storage modulus (G′) (3931.7 Pa), hardness (8.38 N), chewiness (5.41 N), springiness (0.918), cohesiveness (0.766) and WHC (79.6%) compared with others. These results indicated that ultrasound treatment could improve gelation properties of MBPG, especially at 300 W.

Composite Hydrogel for the Targeted Capture and Photothermal Killing of Bacteria toward Facilitating Wound Healing.

Pathogenic infections pose a significant risk to public health and are regarded as one of the most difficult clinical treatment obstacles. A reliable and safe photothermal antibacterial platform is a promising technique for the treatment of bacterial infections. Given the damage that high temperatures cause in normal tissues and cells, a multifunctional hydrogel driven by photothermal energy is created by trapping bacteria to reduce heat transfer loss and conduct low-temperature photothermal sterilization efficiently. The 3-aminobenzene boronic acid (ABA)-modified graphene oxide is combined with carboxymethyl chitosan (CMCS) and cellulose nanocrystalline (CNC) networks to create the ABA-GO/CNC/CMCS composite hydrogel (composite gel). The obtained composite gel displays a uniform three-dimensional network structure, which can be rapidly heated to 48 °C under infrared light irradiation and is beneficial for killing wound infection bacteria and promoting wound healing. The results of animal experiments show that the composite gel significantly reduces inflammation by killing >99.99% of bacteria under near-infrared light irradiation. The result also demonstrates that it increases the granulation tissue thickness and collagen distribution and promotes wound healing. After treatment for 14 days, compared with the remaining 27.73% of the remaining wound area in the control group, the wound area in the composite gel with NIR group is only 0.91%. It significantly accelerates the wound healing process of Staphylococcus aureus infection and shows great potential for clinical application.

Wood-inspired biomimetic vascular evaporator for highly efficient and stable solar steam generation in harsh environments

Solar-driven interfacial evaporation has great potential in freshwater harvesting, but it remains a huge challenge to maintain the structural stability of solar evaporator in complex and harsh environments while ensuring the water evaporation capacity. Herein, inspired by the mechanical stability and water transportation capability of vascular system in natural wood, a biomimetic vascular evaporator (BVE) was prepared by ice template induced self-assembly method for high-efficiency solar energy-driven seawater desalination and wastewater purification in harsh environments. Due to the ice crystals grow vertically and sublimate, the gel was squeezed to form a structure like vascular bundles with a uniform three-dimensional network structure and parallel vascular pores. The experimental results show that the vascular structure of BVE provides effective structural stability that 1000 times of repeated compression at 80% deformation without being destroyed. Meanwhile, integrating rapid water transportation capability, thermal positioning effect, and the reduced vaporization enthalpy endow high evaporation capacity (2.37 kg m−2 h−1, 93.11% pure water efficiency) under 1 sun irradiation. In particular, the above performance of BVE allows it to maintain a high and stable freshwater production capacity in various harsh environments, such as acid and alkali solutions, organic dyes, heavy metal wastewater, and wet soil. This work provides new insights into the rational design of the bionic photothermal evaporator, and demonstrates its potential application in long-term effective wastewater purification in harsh environments.

Synergistic effects of oat β-glucan combined with ultrasound treatment on gel properties of silver carp surimi

The effect of oat β-glucan (OG) combined with ultrasound treatment on the gelation properties of silver carp surimi with different salt contents was investigated. The results demonstrated that the gelation properties of surimi gels at high salt concentration were superior than those at low salt level. The addition of OG or ultrasound treatment could significantly enhance the texture properties, gel strength and water holding capacity (WHC) of gel samples, regardless of salt contents. The ultrasound treatment improved the whiteness of surimi gels, whereas the OG addition slightly declined the whiteness. Both OG addition and ultrasound treatment markedly reduced the total sulfhydryl content (total SH) and strengthened the hydrophobic interactions, forming the more uniform and denser gel network structures, hence more water was captured in network structures and became immobilized. Moreover, the combined treatment of OG and ultrasound showed synergic action on the gelation properties of surimi, and the gel strength and WHC of low-salt surimi gel treated by the combination of OG and ultrasound were even superior than that of high-salt gel without OG by traditional heating.

Effect of carboxymethyl cellulose (CMC) on some physico-chemical and mechanical properties of unrinsed surimi gels

The objective of this study was to evaluate the effect of the carboxymethyl cellulose (CMC) on the physico-chemical and mechanical properties of unrinsed surimi gels during heat treatment. The results revealed that the addition of CMC could significantly (p < 0.05) improve the gel strength, texture properties of unrinsed surimi gels and imparted better color perception compared with the control group showing lower gel strength and poorer water-holding capacity. The addition of 0.5 and 1.5 g/100 g CMC also promoted the formation of a more uniform and compact gel network structure of the unrinsed surimi gels, locking more water in the gel network, significantly improved the water holding capacity of the gels and enhancing their viscoelastic properties (p < 0.05). In conclusion, an appropriate amount of CMC can be added to unrinsed surimi as a food additive, and 1.5 g/100 g was the optimal addition amount obtained in this study, which provides important information for improved the gel properties of unrinsed surimi.