Objective:To observed the effect of a curcumin-based vaginal gel combined with electroporation for the treatment of vulvovaginal candidiasis(VVC)caused by Candida albicans.Methods:Temperature-sensitive in situ gels(IS...Objective:To observed the effect of a curcumin-based vaginal gel combined with electroporation for the treatment of vulvovaginal candidiasis(VVC)caused by Candida albicans.Methods:Temperature-sensitive in situ gels(ISG)were prepared using poloxamers 407 and 188 as matrices.The mass ratio of poloxamer 407 and poloxamer 188 was 7:1 with a gelation temperature of approximately 29℃ and gelation time of 2.5 min.Results:Electroporation increased the transmucosal permeability of the model drug,doxorubicin and improved the antifungal effects of curcumin.In vitro antifungal experiments showed that the number of fungal colonies in curcumin ISG combined with electroporation was lower than that in pure curcumin ISG.In vivo pharmacodynamic experiments showed that,compared to the model group,curcumin ISG with electroporation inhibited the growth of C.albicans,alleviated vaginal mucosal edema,and reduced the inflammatory response.Conclusion:Curcumin ISG combined with electroporation has substantial potential for the efficient clinical treatment of VVC.展开更多
Thermoresponsive hydrogels based on poly(N-isopropylacrylamide)(PNIPAm)often undergo syneresis upon heating,and thus become irrecoverable in shape.To overcome this limitation,we copolymerize tetra-armed PNIPAm precurs...Thermoresponsive hydrogels based on poly(N-isopropylacrylamide)(PNIPAm)often undergo syneresis upon heating,and thus become irrecoverable in shape.To overcome this limitation,we copolymerize tetra-armed PNIPAm precursor with tetra-armed poly(ethylene glycol)(PEG)precursor.After incorporating the hydrophilic PEG components,the hydrogel samples exhibited recoverable swellability during repeated heating-cooling cycles,during which phase segregation occurred,and the water repelled from the PNIPAm-rich phase can be accommodated in the PEG-rich phase.As a result,recoverability relied on the swellability of the PEG-rich phase,which correlated quantitatively with the molar mass and concentration of the precursor solution.This study provides an effective protocol for the molecular design of stimuli-responsive hydrogels with a desired degree of shape recoverability.展开更多
Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential applications.However,during the loading and unloading cycles,a clear stress softening behavior can be observed in man...Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential applications.However,during the loading and unloading cycles,a clear stress softening behavior can be observed in many material systems,which is also named as the Mullins effect.In this work,we aim to provide a complete review of the Mullins effect in soft yet tough materials,specifically focusing on nanocomposite gels,double-network hydrogels,and multi-network elastomers.We first revisit the experimental observations for these soft materials.We then discuss the recent developments of constitutive models,emphasizing novel developments in the damage mechanisms or network representations.Some phenomenological models will also be briefly introduced.Particular attention is then placed on the anisotropic and multiaxial modeling aspects.It is demonstrated that most of the existing models fail to accurately predict the multiaxial data,posing a significant challenge for developing future anisotropic models tailored for tough gels and elastomers.展开更多
Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic h...Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.展开更多
Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical mo...Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt solutions.By minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt concentration.We compare our predictions for the swelling ratio with experimental measurements,which show excellent agreement.In addition,we employ a finite element method to assess the applicability range of our theoretical model and assumptions.We anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.展开更多
The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by text...The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by texture profile analysis(TPA).In addition,the mechanism was analyzed through chemical interactions,protein secondary structure,and microstructure.The results showed that with the addition of different concentrations of SA and CaCl_(2) to the shrimp surimi,the gel quality firstly increased and then decreased with the increase of SA and CaCl_(2) concentrations.The highest values of WHC,breaking force and gel strength were obtained with the addition of 1.2%SA or 0.1%CaCl_(2).When SA and CaCl_(2) were used in concert,the group containing 1.2%SA and 0.15%CaCl_(2) had the highest gel strength with the densest three-dimensional network structure of the gel.In addition,the results of chemical interaction analyses showed that hydrogen and ionic bonds were the main chemical bonds of shrimp surimi sol,while shrimp surimi gel mainly consisted of hydrophobic and disulfide bonds.The incorporation of SA and CaCl_(2) resulted in a significant increase in hydrophobic interactions and disulfide bonding,which could effectively improve the gel properties of shrimp surimi.展开更多
The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These syst...The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These systems can induce specific cell reactions,promote specific tissue functions,and serve as valuable tools for research in tissue engineering,regenerative medicine,and drug discovery.This paper discusses current developments in the field of three-dimensional cell culture and the potential applications of 3D type 1 collagen gels to enhance the growth and maturation of dendritic cells.展开更多
Rapid advancements in flexible electronics technology propel soft tactile sensing devices toward high-level biointegration,even attaining tactile perception capabilities surpassing human skin.However,the inherent mech...Rapid advancements in flexible electronics technology propel soft tactile sensing devices toward high-level biointegration,even attaining tactile perception capabilities surpassing human skin.However,the inherent mechanical mismatch resulting from deficient biomimetic mechanical properties of sensing materials poses a challenge to the application of wearable tactile sensing devices in human-machine interaction.Inspired by the innate biphasic structure of human subcutaneous tissue,this study discloses a skin-compliant wearable iontronic triboelectric gel via phase separation induced by competitive hydrogen bonding.Solvent-nonsolvent interactions are used to construct competitive hydrogen bonding systems to trigger phase separation,and the resulting soft-hard alternating phase-locked structure confers the iontronic triboelectric gel with Young’s modulus(6.8-281.9 kPa)and high tensile properties(880%)compatible with human skin.The abundance of reactive hydroxyl groups gives the gel excellent tribopositive and self-adhesive properties(peel strength>70 N m^(−1)).The self-powered tactile sensing skin based on this gel maintains favorable interface and mechanical stability with the working object,which greatly ensures the high fidelity and reliability of soft tactile sensing signals.This strategy,enabling skin-compliant design and broad dynamic tunability of the mechanical properties of sensing materials,presents a universal platform for broad applications from soft robots to wearable electronics.展开更多
Polyampholyte gels,which have hierarchical structures,exhibit excellent self-healing properties and have great promise for biomaterials and bioengineering.We investigated the relationship between microscopic structure...Polyampholyte gels,which have hierarchical structures,exhibit excellent self-healing properties and have great promise for biomaterials and bioengineering.We investigated the relationship between microscopic structures and macroscopic viscoelastic properties of polyampholyte gels and found three factors influencing their viscoelastic properties,including the chemical crosslinking bonds,topological entanglements controlled by monomer concentration,and the ionic bonds.Ionic strength plays a major role on the strength of ionic bonds.A crossover point of elastic modulus and loss modulus was observed in the dynamic frequency sweeps at low monomer concentration or low chemical crosslinking density for gels with intermediate strength of ionic bonds.The solid-liquid transition signaled by the crossover point is a typical feature of dynamic associated gels,representing the dynamical association-dissociation of the ionic bonds and full relaxation of the topological entanglements in the gel network.While the crossover point disappears when the ionic bonds are too weak or too strong to form“permanent”bonds.Consistently,in the non-linear yielding measurement,gels with intermediate strength of the ionic bonds are ductile and yield at very large shear strain due to the self-healing properties and the dynamic association-dissociation of the ionic bonds.But the self-healing properties disappear when the ionic bond strength is too weak or too strong.Our work reveals the mechanism of how the dynamic association-dissociation of ionic bonds influences both the linear and non-linear viscoelastic properties of the polyampholyte gels.展开更多
In the heterogeneous reservoirs,CO_(2) flooding easily leads to CO_(2) gas channeling,which can seriously affect sweeping efficiency and reduce oil recovery.After thoroughly investigating the advantages and shortcomin...In the heterogeneous reservoirs,CO_(2) flooding easily leads to CO_(2) gas channeling,which can seriously affect sweeping efficiency and reduce oil recovery.After thoroughly investigating the advantages and shortcomings of various CO_(2) plugging technologies,this paper focuses on the feasibility of improving conventional water-alternating gas(WAG)through CO_(2)-responsive gel materials.Based on the different chemical reaction mechanisms between the unique chemical structure and CO_(2),changes in the material’s physical and chemical properties can respond to CO_(2).The feasibility of utilizing these property changes for CO_(2)-responsive plugging is explored.Various CO_(2)-responsive gels and gel nanoparticles have been extensively researched in different fields,such as energy,medicine,and biology.This paper surveys the molecular structures,chemical compositions,response mechanisms,and changes of these CO_(2)-responsive gels,aiming to draw insights into the carbon dioxide-enhanced oil recovery(CO_(2)-EOR)field.Finally,the key issues and future development direction of CO_(2)-responsive plugging gels were analyzed.展开更多
This study evaluates the performance of polymer fire-retardant and extinguishing gels through experimental comparisons with traditional foam extinguishing agents and water.The findings indicate that polymer fire-retar...This study evaluates the performance of polymer fire-retardant and extinguishing gels through experimental comparisons with traditional foam extinguishing agents and water.The findings indicate that polymer fire-retardant and extinguishing gels exhibit significant advantages over conventional water and foam in terms of fire suppression and prevention of re-ignition.Based on these results,the fire retardant mechanisms of the polymer gel are hypothesized.展开更多
Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synth...Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synthesis of macro molecular building blocks,and direct gelation between natural polyphenols and small molecule boranic acids is yet to be investigated.In this study,we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids.Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols.The gels showed multi-responsiveness,such as acid-,base-,reduction-and oxidantsensitive depending on the used boronic acid building blocks.The chemistry for gel formation and stimuli-responsiveness was characterized by11B NMR spectroscopy.The multi-stimuli responsiveness,green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.展开更多
In this paper, microscopic characteristics of preformed gels （PGs） and secondary cross-linked gels （SCG） with the same concentration were analyzed by atomic force microscopy （AFM）. Experimental results indicate ...In this paper, microscopic characteristics of preformed gels （PGs） and secondary cross-linked gels （SCG） with the same concentration were analyzed by atomic force microscopy （AFM）. Experimental results indicate that the microstructure of secondary cross-linked gels is a thick 3-D network, in which micro-holes and irregular macro-holes are embedded. The maximum width of the irregular macro-holes is 200 nm. In the SCG two different chemical bonds were formed, which leads to the structural inhomogeneity and the asymmetry of the crosslinking density. The structural inhomogeneity of SCG results in the formation of irregular macro-holes. The excessive cross-linking density is the primary reason for dehydration of SCG and the presence of irregular macro-holes in SCG can facilitate dehydration.展开更多
Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of ...Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of HPMC K4M or carbopol 934P and pluronic F127. Optimized formulations were examined through measuring gelation temperature, rheology speciality, drug release behavior, pharmacokinetics and ocular irritation. Results The gelation temperature was reduced by adding HPMC K4M or carbopol 934P, and the viscosity was enhanced slightly. Either HPMC K4M or carbopol 934P delayed the release of PCV from in situ gel. PCV was released by non-Fickian diffusion. The study of ocular irritation for different PCV formulations did not show any irritation or damage for the cornea. PCV bioavailability from combination of carbopol 934P and pluronic F127 gels was higher than that obtained from any other gels. Conclusion Pluronic F127 formulations of PCV can be used as liquid for administration by instilling into the eye. Facilitated by the appropriate eye temperature, the formulations were transformed to gel phase. On the basis of in vitro and in vivo results, PCV formulations containing HPMC K4M or carbopol 934P and low concentration of pluronic F127 （12%） showed potential for use as a drug delivery system with improved ocular bioavailability.展开更多
The BST oilfield in the northwestern Taklamakan Desert is a fractured carbonate reservoir,but issues of water breakthrough are becoming increasingly severe with the development of water flooding.Unfortunately,the high...The BST oilfield in the northwestern Taklamakan Desert is a fractured carbonate reservoir,but issues of water breakthrough are becoming increasingly severe with the development of water flooding.Unfortunately,the high-temperature and high-salt conditions(130°C,71695 mg/L)of the BST oilfield pose challenges for the development of plugging agents.In this study,the effects of 2-acrylamido-2-methylpropane sulfonic acid(AMPS)content on AM/AMPS copolymers and gels were studied through viscosity measurements,nuclear magnetic resonance(NMR),and cryo-scanning electron microscope(Cryo-SEM).Moreover,the AMPS stabilization mechanism of the polymers and gels was explained.Heatresistant and salt-tolerant gel systems were developed,and their gelation properties,thermal stability,injection capacity,and plugging ability were evaluated.Experimental results showed inconsistencies between the effects of AMPS content on the polymers and gels.For the polymers,the thermal stability increased with increased AMPS content in the polymer.However,excessive AMPS content resulted in poor gelation and low strength.The developed gel systems with S30 polymer(AMPS content is approximately 26%)exhibited excellent thermal stability,controllable gelation time,good injection capacity,and plugging ability.The field application results indicated that most production wells had a positive response,with reduced water-cut and increased daily oil production.展开更多
To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration p...To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration products,degree of hydration of the slag,and the degree of polymerization of C-A-S-H gels of binders were examined.The experimental results indicate that the pH of the pore solution increased with an increase in the Na_(2)O concentration.However,mortar with an optimum compressive strength value of 81.0 MPa at 28 d was obtained when water glass modulus was 1.5.The main hydration product is a C-A-S-H gel for which the quantity and the degree of polymerization depend strongly on the Na_(2)O concentration;for a given range,both increase with increasing Na_(2)O concentration,thus yielding an enhanced strength.A further increase in the Na_(2)O concentration continuously increases the quantity of C-A-S-H gels while drastically reducing the degree of polymerization.The positive effect of the former is counteracted by the adverse effect of the latter,ultimately,leading to a decreased strength.Furthermore,we reveal that the degree of polymerization for C-A-S-H gels may be affected by pH,through a series of complex chemical reactions.展开更多
Introduction The formation of gelatin-containing mieroemulsionbased gels（MBGs） was first described in 1986 and the physical/structural characterization was carried out by a number of groups with a variety of techni...Introduction The formation of gelatin-containing mieroemulsionbased gels（MBGs） was first described in 1986 and the physical/structural characterization was carried out by a number of groups with a variety of techniques including tracer diffusion, electrical conductivity, NMR, X-ray and small angle neutron scattering. The MBGs were proposed to comprise an extensive, rigid, interconnected network of gelatin/water rods stabilized by a monolayer of surfactant, in coexistence with a po- pulation of conventional W/O microemulsion droplets.展开更多
This paper examines literature that claims,suggests,or implies that floods with"colloidal dispersion gels"(CDGs)are superior to polymer floods for oil recovery.The motivation for this report is simple.If CDG...This paper examines literature that claims,suggests,or implies that floods with"colloidal dispersion gels"(CDGs)are superior to polymer floods for oil recovery.The motivation for this report is simple.If CDGs can propagate deep into the porous rock of a reservoir,and at the same time,provide resistance factors or residual resistance factors that are greater than those for the same polymer formulation without the crosslinker,then CDGs should be used in place of polymer solutions for most/all polymer,surfactant,and ASP floods.In contrast,if the claims are not valid,(1)money spent on crosslinker in the CDG formulations was wasted,(2)the mobility reduction/mobility control for CDG field projects was under-designed,and(3)reservoir performance could have been damaged by excessive loss of polymer,face-plugging by gels,and/or excessive fracture extension.From this review,the clear answer is that there is no credible evidence that colloidal dispersion gels can propagate deep into the porous rock of a reservoir,and at the same time,provide resistance factors or residual resistance factors that are greater than those for the same polymer formulation without the crosslinker.CDGs have been sold using a number of misleading and invalid arguments.Very commonly,Hall plots are claimed to demonstrate that CDGs provide higher resistance factors and/or residual resistance factors than normal polymer solutions.However,because Hall plots only monitor injection pressures at the wellbore,they reflect the composite of face plugging/formation damage,in-situ mobility changes,and fracture extension.Hall plots cannot distinguish between these effects-so they cannot quantify in situ resistance factors or residual resistance factors.Laboratory studiesdwhere CDG gelants were forced through short cores during 2-3 h-have incorrectly been cited as proof that CDGs will propagate deep(hundreds of feet)into the porous rock of a reservoir over the course of months.In contrast,most legitimate laboratory studies reveal that the gelation time for CDGs is a day or less and that CDGs will not propagate through porous rock after gelation.A few cases were noted where highly depleted Al and/or HPAM fluids passed through cores after one week of aging.Details about these particular formulations/experiments were sparse and questions remain about their reproducibility.No credible evidence indicates that the CDG can propagate deep into a reservoir(over the course of weeks or months)and still provide a greater effect than that from the polymer alone.With one exception,aluminum from the CDG was never reported to be produced in a field application.In the exception,Chang reported producing 1-20%of the injected aluminum concentration.The available evidence suggests that some free(unreacted)HPAM and aluminum that was associated with the original CDG can propagate through porous media.However,there is no evidence that this HPAM or aluminum provides mobility reduction greater than that for the polymer formulation without crosslinker.展开更多
Stimuli-responsive polymer gels have recently attracted great attention due to their heat/solvent resistance,dimensional stability,and unique sensitivity to external stimuli.In this work,we synthesized thiol-functiona...Stimuli-responsive polymer gels have recently attracted great attention due to their heat/solvent resistance,dimensional stability,and unique sensitivity to external stimuli.In this work,we synthesized thiol-functionalized tetraphenylethylene(TPE)and constructed polymer gels through thiol-ene click reaction.The synthetic process of the polymer gels could be monitored by fluorescence emission of TPE moieties based on aggregation-induced emission mechanism.In addition,due to the dual redox-and acid responsiveness of the polymer gels,in the presence of dithiothreitol and trifluoroacetic acid,fluorescence quenching of the polymer gels can be observed.This stimuli-responsive characteristics endows the polymer gels with potential applications in fluorescent sensing and imaging,cancer diagnosis and selfhealing materials.展开更多
基金supported by the Beijing Natural Science Foundation(L222126).
文摘Objective:To observed the effect of a curcumin-based vaginal gel combined with electroporation for the treatment of vulvovaginal candidiasis(VVC)caused by Candida albicans.Methods:Temperature-sensitive in situ gels(ISG)were prepared using poloxamers 407 and 188 as matrices.The mass ratio of poloxamer 407 and poloxamer 188 was 7:1 with a gelation temperature of approximately 29℃ and gelation time of 2.5 min.Results:Electroporation increased the transmucosal permeability of the model drug,doxorubicin and improved the antifungal effects of curcumin.In vitro antifungal experiments showed that the number of fungal colonies in curcumin ISG combined with electroporation was lower than that in pure curcumin ISG.In vivo pharmacodynamic experiments showed that,compared to the model group,curcumin ISG with electroporation inhibited the growth of C.albicans,alleviated vaginal mucosal edema,and reduced the inflammatory response.Conclusion:Curcumin ISG combined with electroporation has substantial potential for the efficient clinical treatment of VVC.
基金financially supported by the National Natural Science Foundation of China(No.22173095)。
文摘Thermoresponsive hydrogels based on poly(N-isopropylacrylamide)(PNIPAm)often undergo syneresis upon heating,and thus become irrecoverable in shape.To overcome this limitation,we copolymerize tetra-armed PNIPAm precursor with tetra-armed poly(ethylene glycol)(PEG)precursor.After incorporating the hydrophilic PEG components,the hydrogel samples exhibited recoverable swellability during repeated heating-cooling cycles,during which phase segregation occurred,and the water repelled from the PNIPAm-rich phase can be accommodated in the PEG-rich phase.As a result,recoverability relied on the swellability of the PEG-rich phase,which correlated quantitatively with the molar mass and concentration of the precursor solution.This study provides an effective protocol for the molecular design of stimuli-responsive hydrogels with a desired degree of shape recoverability.
基金supported by the National Natural Science Foundation of China(Grant Nos.12321002,12211530061,12022204,and 12202378)the Zhejiang Provincial Natural Science Foundation of China(Grant No.LD22A020001)the 111 Project(Grant No.B21034).
文摘Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential applications.However,during the loading and unloading cycles,a clear stress softening behavior can be observed in many material systems,which is also named as the Mullins effect.In this work,we aim to provide a complete review of the Mullins effect in soft yet tough materials,specifically focusing on nanocomposite gels,double-network hydrogels,and multi-network elastomers.We first revisit the experimental observations for these soft materials.We then discuss the recent developments of constitutive models,emphasizing novel developments in the damage mechanisms or network representations.Some phenomenological models will also be briefly introduced.Particular attention is then placed on the anisotropic and multiaxial modeling aspects.It is demonstrated that most of the existing models fail to accurately predict the multiaxial data,posing a significant challenge for developing future anisotropic models tailored for tough gels and elastomers.
基金the National Natural Science Foundation of China(22265021)the Aeronautical Science Foundation of China(2020Z056056003).
文摘Metal–organic gel(MOG)derived composites are promising multi-functional materials due to their alterable composition,identifiable chemical homogeneity,tunable shape,and porous structure.Herein,stable metal–organic hydrogels are prepared by regulating the complexation effect,solution polarity and curing speed.Meanwhile,collagen peptide is used to facilitate the fabrication of a porous aerogel with excellent physical properties as well as the homogeneous dispersion of magnetic particles during calcination.Subsequently,two kinds of heterometallic magnetic coupling systems are obtained through the application of Kirkendall effect.FeCo/nitrogen-doped carbon(NC)aerogel demonstrates an ultra-strong microwave absorption of−85 dB at an ultra-low loading of 5%.After reducing the time taken by atom shifting,a FeCo/Fe3O4/NC aerogel containing virus-shaped particles is obtained,which achieves an ultra-broad absorption of 7.44 GHz at an ultra-thin thickness of 1.59 mm due to the coupling effect offered by dual-soft-magnetic particles.Furthermore,both aerogels show excellent thermal insulation property,and their outstanding radar stealth performances in J-20 aircraft are confirmed by computer simulation technology.The formation mechanism of MOG is also discussed along with the thermal insulation and electromagnetic wave absorption mechanism of the aerogels,which will enable the development and application of novel and lightweight stealth coatings.
基金supported by the National Natural Science Foundation of China(No.12372259).
文摘Polyelectrolyte(PE)gels,distinguished by their unique stimuli-responsive swelling behavior,serve as the basis of broad applications,such as artificial muscles and drug delivery.In this work,we present a theoretical model to analyze the electrostatics and its contribution to the swelling behavior of PE gels in salt solutions.By minimizing the free energy of PE gels,we obtain two distinct scaling regimes for the swelling ratio at equilibrium with respect to the salt concentration.We compare our predictions for the swelling ratio with experimental measurements,which show excellent agreement.In addition,we employ a finite element method to assess the applicability range of our theoretical model and assumptions.We anticipate that our model will also provide valuable insights into drug adsorption and release,deformation of red blood cells,4D printing and soft robotics,where the underlying mechanism of swelling remains enigmatic.
基金supported by the Public Welfare Project of Ningbo(No.2022S211)the National Key R&D Program of China(No.2020YFD0900903)。
文摘The object of this study is to investigate the effects of sodium alginate(SA)and CaCl_(2) on the physicochemical characteristics of shrimp surimi by studying gel strength,water holding capacity(WHC),as well as by texture profile analysis(TPA).In addition,the mechanism was analyzed through chemical interactions,protein secondary structure,and microstructure.The results showed that with the addition of different concentrations of SA and CaCl_(2) to the shrimp surimi,the gel quality firstly increased and then decreased with the increase of SA and CaCl_(2) concentrations.The highest values of WHC,breaking force and gel strength were obtained with the addition of 1.2%SA or 0.1%CaCl_(2).When SA and CaCl_(2) were used in concert,the group containing 1.2%SA and 0.15%CaCl_(2) had the highest gel strength with the densest three-dimensional network structure of the gel.In addition,the results of chemical interaction analyses showed that hydrogen and ionic bonds were the main chemical bonds of shrimp surimi sol,while shrimp surimi gel mainly consisted of hydrophobic and disulfide bonds.The incorporation of SA and CaCl_(2) resulted in a significant increase in hydrophobic interactions and disulfide bonding,which could effectively improve the gel properties of shrimp surimi.
文摘The three-dimensional(3D)cell culture system has garnered significant attention in recent years as a means of studying cell behavior and tissue development,as opposed to traditional two-dimensional cultures.These systems can induce specific cell reactions,promote specific tissue functions,and serve as valuable tools for research in tissue engineering,regenerative medicine,and drug discovery.This paper discusses current developments in the field of three-dimensional cell culture and the potential applications of 3D type 1 collagen gels to enhance the growth and maturation of dendritic cells.
基金supported by the National Natural Science Foundation of China(22278091)the Guangxi Natural Science Foundation of China(2023GXNSFFA026009)+1 种基金All the experiments with human research participants were approved by the Medical Ethics Committee of Guangxi University(GXU-2023-023)informed written consent was obtained from all participants.
文摘Rapid advancements in flexible electronics technology propel soft tactile sensing devices toward high-level biointegration,even attaining tactile perception capabilities surpassing human skin.However,the inherent mechanical mismatch resulting from deficient biomimetic mechanical properties of sensing materials poses a challenge to the application of wearable tactile sensing devices in human-machine interaction.Inspired by the innate biphasic structure of human subcutaneous tissue,this study discloses a skin-compliant wearable iontronic triboelectric gel via phase separation induced by competitive hydrogen bonding.Solvent-nonsolvent interactions are used to construct competitive hydrogen bonding systems to trigger phase separation,and the resulting soft-hard alternating phase-locked structure confers the iontronic triboelectric gel with Young’s modulus(6.8-281.9 kPa)and high tensile properties(880%)compatible with human skin.The abundance of reactive hydroxyl groups gives the gel excellent tribopositive and self-adhesive properties(peel strength>70 N m^(−1)).The self-powered tactile sensing skin based on this gel maintains favorable interface and mechanical stability with the working object,which greatly ensures the high fidelity and reliability of soft tactile sensing signals.This strategy,enabling skin-compliant design and broad dynamic tunability of the mechanical properties of sensing materials,presents a universal platform for broad applications from soft robots to wearable electronics.
基金supported by the National Natural Science Foundation of China(No.22273114)the National Key R&D Program of China(No.2023YFE0124500)+1 种基金the National Key R&D Program of China(No.2023YFC2411203)International Partnership Program of the Chinese Academy of Sciences(No.027GJHZ2022061FN).
文摘Polyampholyte gels,which have hierarchical structures,exhibit excellent self-healing properties and have great promise for biomaterials and bioengineering.We investigated the relationship between microscopic structures and macroscopic viscoelastic properties of polyampholyte gels and found three factors influencing their viscoelastic properties,including the chemical crosslinking bonds,topological entanglements controlled by monomer concentration,and the ionic bonds.Ionic strength plays a major role on the strength of ionic bonds.A crossover point of elastic modulus and loss modulus was observed in the dynamic frequency sweeps at low monomer concentration or low chemical crosslinking density for gels with intermediate strength of ionic bonds.The solid-liquid transition signaled by the crossover point is a typical feature of dynamic associated gels,representing the dynamical association-dissociation of the ionic bonds and full relaxation of the topological entanglements in the gel network.While the crossover point disappears when the ionic bonds are too weak or too strong to form“permanent”bonds.Consistently,in the non-linear yielding measurement,gels with intermediate strength of the ionic bonds are ductile and yield at very large shear strain due to the self-healing properties and the dynamic association-dissociation of the ionic bonds.But the self-healing properties disappear when the ionic bond strength is too weak or too strong.Our work reveals the mechanism of how the dynamic association-dissociation of ionic bonds influences both the linear and non-linear viscoelastic properties of the polyampholyte gels.
基金Supported by the Open Fund Project of Hubei Key Laboratory of Oil and Gas Drilling and Production Engineering(YQZC202105)Yangtze University Student Innovation Program(Yz2022018).
文摘In the heterogeneous reservoirs,CO_(2) flooding easily leads to CO_(2) gas channeling,which can seriously affect sweeping efficiency and reduce oil recovery.After thoroughly investigating the advantages and shortcomings of various CO_(2) plugging technologies,this paper focuses on the feasibility of improving conventional water-alternating gas(WAG)through CO_(2)-responsive gel materials.Based on the different chemical reaction mechanisms between the unique chemical structure and CO_(2),changes in the material’s physical and chemical properties can respond to CO_(2).The feasibility of utilizing these property changes for CO_(2)-responsive plugging is explored.Various CO_(2)-responsive gels and gel nanoparticles have been extensively researched in different fields,such as energy,medicine,and biology.This paper surveys the molecular structures,chemical compositions,response mechanisms,and changes of these CO_(2)-responsive gels,aiming to draw insights into the carbon dioxide-enhanced oil recovery(CO_(2)-EOR)field.Finally,the key issues and future development direction of CO_(2)-responsive plugging gels were analyzed.
基金Supported by Central Finance Forestry Science and Technology Promotion Demonstration Project(H[2023]TG31).
文摘This study evaluates the performance of polymer fire-retardant and extinguishing gels through experimental comparisons with traditional foam extinguishing agents and water.The findings indicate that polymer fire-retardant and extinguishing gels exhibit significant advantages over conventional water and foam in terms of fire suppression and prevention of re-ignition.Based on these results,the fire retardant mechanisms of the polymer gel are hypothesized.
基金supported by the National Natural Science Foundation of China(No.21725402)the Shanghai Municipal Science and Technology Commission(No.17XD1401600)。
文摘Reversible boronate-catechol linkage was widely used to construct two-dimensional coatings and threedimensional nanostructures or hydrogels.The construction of these functional materials usually requires the pre-synthesis of macro molecular building blocks,and direct gelation between natural polyphenols and small molecule boranic acids is yet to be investigated.In this study,we fabricated a family of allsmall-molecule dynamic covalent gels consisting of tannic acid and boronic acids.Transparent and thixotropic gels were formed by boronate affinity towards catechol groups abundant on natural polyphenols.The gels showed multi-responsiveness,such as acid-,base-,reduction-and oxidantsensitive depending on the used boronic acid building blocks.The chemistry for gel formation and stimuli-responsiveness was characterized by11B NMR spectroscopy.The multi-stimuli responsiveness,green processing and facile modular design make the boronic acid-tannic acid gels promising candidates for the development of smart soft materials.
文摘In this paper, microscopic characteristics of preformed gels （PGs） and secondary cross-linked gels （SCG） with the same concentration were analyzed by atomic force microscopy （AFM）. Experimental results indicate that the microstructure of secondary cross-linked gels is a thick 3-D network, in which micro-holes and irregular macro-holes are embedded. The maximum width of the irregular macro-holes is 200 nm. In the SCG two different chemical bonds were formed, which leads to the structural inhomogeneity and the asymmetry of the crosslinking density. The structural inhomogeneity of SCG results in the formation of irregular macro-holes. The excessive cross-linking density is the primary reason for dehydration of SCG and the presence of irregular macro-holes in SCG can facilitate dehydration.
文摘Aim To develop pluronic F127 （PF127） based formulations of penciclovir （PCV） aimed at enhancing its ocular bioavailability. Methods Thermosensitive in situ gels of penciclovir were prepared through combination of HPMC K4M or carbopol 934P and pluronic F127. Optimized formulations were examined through measuring gelation temperature, rheology speciality, drug release behavior, pharmacokinetics and ocular irritation. Results The gelation temperature was reduced by adding HPMC K4M or carbopol 934P, and the viscosity was enhanced slightly. Either HPMC K4M or carbopol 934P delayed the release of PCV from in situ gel. PCV was released by non-Fickian diffusion. The study of ocular irritation for different PCV formulations did not show any irritation or damage for the cornea. PCV bioavailability from combination of carbopol 934P and pluronic F127 gels was higher than that obtained from any other gels. Conclusion Pluronic F127 formulations of PCV can be used as liquid for administration by instilling into the eye. Facilitated by the appropriate eye temperature, the formulations were transformed to gel phase. On the basis of in vitro and in vivo results, PCV formulations containing HPMC K4M or carbopol 934P and low concentration of pluronic F127 （12%） showed potential for use as a drug delivery system with improved ocular bioavailability.
基金Financial support from the Major Scientific and Technological Project of CNPC under grant number ZD2019-183-007Sinopec Northwest Company of China for the financial support(34400007-17-ZC06070095)
文摘The BST oilfield in the northwestern Taklamakan Desert is a fractured carbonate reservoir,but issues of water breakthrough are becoming increasingly severe with the development of water flooding.Unfortunately,the high-temperature and high-salt conditions(130°C,71695 mg/L)of the BST oilfield pose challenges for the development of plugging agents.In this study,the effects of 2-acrylamido-2-methylpropane sulfonic acid(AMPS)content on AM/AMPS copolymers and gels were studied through viscosity measurements,nuclear magnetic resonance(NMR),and cryo-scanning electron microscope(Cryo-SEM).Moreover,the AMPS stabilization mechanism of the polymers and gels was explained.Heatresistant and salt-tolerant gel systems were developed,and their gelation properties,thermal stability,injection capacity,and plugging ability were evaluated.Experimental results showed inconsistencies between the effects of AMPS content on the polymers and gels.For the polymers,the thermal stability increased with increased AMPS content in the polymer.However,excessive AMPS content resulted in poor gelation and low strength.The developed gel systems with S30 polymer(AMPS content is approximately 26%)exhibited excellent thermal stability,controllable gelation time,good injection capacity,and plugging ability.The field application results indicated that most production wells had a positive response,with reduced water-cut and increased daily oil production.
基金Funded by the National Natural Science Foundation of China(No.51674161)the Natural Science Foundation of Shandong Province(No.ZR2019BEE075)+1 种基金the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents(No.2019RCJJ007)the Young Science and Technology Innovation Program of Shandong Province(No.2020KJD001)。
文摘To investigate the variation in the degree of polymerization calcium aluminium silicate hydrate(C-A-S-H)gel and its role in the evolution of the strength of waterglass slag binders,the compressive strength,hydration products,degree of hydration of the slag,and the degree of polymerization of C-A-S-H gels of binders were examined.The experimental results indicate that the pH of the pore solution increased with an increase in the Na_(2)O concentration.However,mortar with an optimum compressive strength value of 81.0 MPa at 28 d was obtained when water glass modulus was 1.5.The main hydration product is a C-A-S-H gel for which the quantity and the degree of polymerization depend strongly on the Na_(2)O concentration;for a given range,both increase with increasing Na_(2)O concentration,thus yielding an enhanced strength.A further increase in the Na_(2)O concentration continuously increases the quantity of C-A-S-H gels while drastically reducing the degree of polymerization.The positive effect of the former is counteracted by the adverse effect of the latter,ultimately,leading to a decreased strength.Furthermore,we reveal that the degree of polymerization for C-A-S-H gels may be affected by pH,through a series of complex chemical reactions.
基金Supported by the Natural Science Foundation of Shandong Province in China(No.Y2003B01).
文摘Introduction The formation of gelatin-containing mieroemulsionbased gels（MBGs） was first described in 1986 and the physical/structural characterization was carried out by a number of groups with a variety of techniques including tracer diffusion, electrical conductivity, NMR, X-ray and small angle neutron scattering. The MBGs were proposed to comprise an extensive, rigid, interconnected network of gelatin/water rods stabilized by a monolayer of surfactant, in coexistence with a po- pulation of conventional W/O microemulsion droplets.
文摘This paper examines literature that claims,suggests,or implies that floods with"colloidal dispersion gels"(CDGs)are superior to polymer floods for oil recovery.The motivation for this report is simple.If CDGs can propagate deep into the porous rock of a reservoir,and at the same time,provide resistance factors or residual resistance factors that are greater than those for the same polymer formulation without the crosslinker,then CDGs should be used in place of polymer solutions for most/all polymer,surfactant,and ASP floods.In contrast,if the claims are not valid,(1)money spent on crosslinker in the CDG formulations was wasted,(2)the mobility reduction/mobility control for CDG field projects was under-designed,and(3)reservoir performance could have been damaged by excessive loss of polymer,face-plugging by gels,and/or excessive fracture extension.From this review,the clear answer is that there is no credible evidence that colloidal dispersion gels can propagate deep into the porous rock of a reservoir,and at the same time,provide resistance factors or residual resistance factors that are greater than those for the same polymer formulation without the crosslinker.CDGs have been sold using a number of misleading and invalid arguments.Very commonly,Hall plots are claimed to demonstrate that CDGs provide higher resistance factors and/or residual resistance factors than normal polymer solutions.However,because Hall plots only monitor injection pressures at the wellbore,they reflect the composite of face plugging/formation damage,in-situ mobility changes,and fracture extension.Hall plots cannot distinguish between these effects-so they cannot quantify in situ resistance factors or residual resistance factors.Laboratory studiesdwhere CDG gelants were forced through short cores during 2-3 h-have incorrectly been cited as proof that CDGs will propagate deep(hundreds of feet)into the porous rock of a reservoir over the course of months.In contrast,most legitimate laboratory studies reveal that the gelation time for CDGs is a day or less and that CDGs will not propagate through porous rock after gelation.A few cases were noted where highly depleted Al and/or HPAM fluids passed through cores after one week of aging.Details about these particular formulations/experiments were sparse and questions remain about their reproducibility.No credible evidence indicates that the CDG can propagate deep into a reservoir(over the course of weeks or months)and still provide a greater effect than that from the polymer alone.With one exception,aluminum from the CDG was never reported to be produced in a field application.In the exception,Chang reported producing 1-20%of the injected aluminum concentration.The available evidence suggests that some free(unreacted)HPAM and aluminum that was associated with the original CDG can propagate through porous media.However,there is no evidence that this HPAM or aluminum provides mobility reduction greater than that for the polymer formulation without crosslinker.
基金supported by the National Natural Science Foundation of China (No.51773190 and No.51973206)。
文摘Stimuli-responsive polymer gels have recently attracted great attention due to their heat/solvent resistance,dimensional stability,and unique sensitivity to external stimuli.In this work,we synthesized thiol-functionalized tetraphenylethylene(TPE)and constructed polymer gels through thiol-ene click reaction.The synthetic process of the polymer gels could be monitored by fluorescence emission of TPE moieties based on aggregation-induced emission mechanism.In addition,due to the dual redox-and acid responsiveness of the polymer gels,in the presence of dithiothreitol and trifluoroacetic acid,fluorescence quenching of the polymer gels can be observed.This stimuli-responsive characteristics endows the polymer gels with potential applications in fluorescent sensing and imaging,cancer diagnosis and selfhealing materials.
