Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this ...Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this study,novel poly(ε-caprolactone)(PCL)-poly(2-vinyl)ethylene glycol(PVEG)copolymers bearing multi-pendant vinyl groups is synthesized by branched-selective allylic etherification polymerization of vinylethylene carbonate(VEC)with linear and tetra-arm PCLs under a synergistic catalysis of palladium complex and boron reagent.Facile thiol-ene photo-click reaction of PCL-PVEG copolymers with multifunctional thiols can rapidly access a serious crosslinked SMPs with high shape memory performance.The thermal properties,mechanical properties and response temperature of the obtained SMPs are tunable by the variation of PCL prepolymers,vinyl contents and functionality of thiols.Moreover,high elastic modulus in the rubbery plateau region can be maintained effectively owing to high-density topological networks of the PCL materials.In addition,the utility of the present SMPs is further demonstrated by the post-functionalization via thiol-ene photo-click chemistry.展开更多
As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(H...As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(HKL)is limited due to its poor crosslinking reactivity.Hence,for the first time,the present study reports the facile oxidation of HKL involving a redox reaction with silver-ammonia complexes([(AgNH3)2]+),primarily focusing on oxidation to produce reactive quinones and promote C-C linkages during reaction.This study aims to increases reactivity of oxidized HKL for effective crosslinking with monoethanolamine(MEA)for the development of bio-based wood adhesives.The characterization,including 13C-nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy,confirms the oxidation reaction,such as the formation of quinones(C=O)and subsequent crosslinking between the oxidized HKL molecules and MEA.Additionally,gel permeation chromatography(GPC)confirms the C-C and C-O linkages with increased molecular weight after oxidation,and is supported by differential scanning calorimetry(DSC)which shows the exothermic reaction due to the crosslinking of the oxidized HKL molecules via condensation to form C-C and C-O linkages.The crosslinked HKL/MEA-based adhesives underwent mild reaction and achieved a maximum dry shear strength of 0.77 MPa,which exceeds the standard requirement of 0.6 MPa.These findings demonstrate not only a one-pot oxidation for improving the reactivity of HKL using silver complexes,but also its facile crosslinking with MEA for sustainable bio-based wood adhesives.展开更多
It is urgent to develop high-performance polyimide(PI)films that simultaneously exhibit high transparency,exceptional thermal stability,mechanical robustness,and low dielectric to fulfil the requirements of flexible d...It is urgent to develop high-performance polyimide(PI)films that simultaneously exhibit high transparency,exceptional thermal stability,mechanical robustness,and low dielectric to fulfil the requirements of flexible display technologies.Herein,a series of fluorinated polyimide films(FPIs)were fabricated by the condensation of 5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione)(6FDA)and the fluorinated triphenylmethane diamine monomer(EDA,MEDA and DMEDA)with heat-crosslinkable tetrafluorostyrene side groups,which was incorporated by different numbers of methyl groups pendant in the ortho position of amino groups.Subsequently,the FPI films underwent heating to produce crosslinking FPIs(C-FPIs)through the self-crosslinking of double bonds in the tetrafluorostyrene.The transparency,solvent resistance,thermal stability,mechanical robustness and dielectric properties of FPI and C-FPI films can be tuned by the number of methyl groups and crosslinking,which were deeply investigated by virtue of molecular dynamics(MD)simulations and density functional theory(DFT).As a result,all the films exhibited exceptional optically colorless and transparent,with transmittance in the visible region of 450-700 nm exceeding 79.9%,and the cut-off wavelengths(λ_(off))were nearly 350 nm.The thermal decomposition temperatures at 5% weight loss(T_(d5%))for all samples exceeded 504℃.These films exhibited a wide range of tunable tensile strength(46.5-75.1 MPa).Significantly,they showed exceptional dielectric properties with the dielectric constant of 2.3-2.5 at full frequency(10^(7)-20 Hz).This study not only highlights the relationship between the polymer molecular structure and properties,but offer insights for balancing optical transparency,heat resistance and low dielectric constant in PI films.展开更多
Heavy metal pollution poses serious risks to the human health and the natural environment,and there is an urgent need to develop efficient heavy metal removal technologies.The adsorption strategy is one of the most fa...Heavy metal pollution poses serious risks to the human health and the natural environment,and there is an urgent need to develop efficient heavy metal removal technologies.The adsorption strategy is one of the most famous strategies for the capture of heavy metal ions.In recent years,hyper crosslinked polymers(HCPs),a kind of hyper crosslinked porous material prepared by Friedel-Crafts alkylation reaction,have attracted more and more attention because of their advantages of ultra-light framework,wide range of building monomers,easy modification and functionalization.This review focuses on the advances of HCPs in the efficient applications to the removal of heavy metal ions.The fundamentals are presented including physicochemical properties,adsorption mechanism,and preparation strategies.Subsequently,the application and influencing factors of HCPs toward heavy metal ion adsorption are discussed in detail.Furthermore,the opportunities and challenges of HCPs in this promising research field are summarized and anticipated.We are convinced that the advanced HCP-based materials will make further contributions to heavy metal removal in wastewater treatment,further paving the way of advancing researches in this field.展开更多
Reader proteins that bind specific methyllysine are important to biological functions of lysine methylation,but readers of many methyllysine sites are still unknown.Therefore,development of covalent probes is importan...Reader proteins that bind specific methyllysine are important to biological functions of lysine methylation,but readers of many methyllysine sites are still unknown.Therefore,development of covalent probes is important to identify readers from cell samples so as to understand biological roles of lysine methylation.Generally,readers bind methyllysine via aromatic cages that contain tryptophan,tyrosine and phenylalanine,that offer a unique motif for selective crosslinking.We recently reported a site-selective tryptophan crosslinking strategy based on dimethylsulfonium that mimics dimethyllysine to crosslink tryptophan in aromatic cages of readers.Since tyrosine is a key residue for binding affinity to methyllysine,especially some readers that do not contain tryptophan residues in the binding pocket.Here we developed strategies of site-selective crosslinking to tyrosine.Ultraviolet(UV)source was applied to excite tyrosine at neutral pH or phenoxide at basic p H,and subsequent single-electron transfer(SET)from Tyr*to sulfonium inside the binding pocket enables selective crosslinking.In consequence,methyllysine readers with tyrosine-containing aromatic cages could be selectively crosslinked by site-specific sulfonium peptide probes.In addition,we expanded substrates from aromatic cages to tyrosine residues of proximate contact with sulfonium probes.The pair of LgBiT and SmBiT exhibited orthogonal crosslinking in complicated cell samples.As a result,we may expand sulfonium tools to target local tyrosine in future investigations.展开更多
High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally c...High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally challenging.Here,we report a general material design strategy to enhance energy storage performance at high temperatures by crosslinking a polar polymer and a high glass-transition temperature polymer as a crosslinked binary blend.Such crosslinked binary polymers display a temperature-insensitive and high energy density behavior of about6.2~8.5 J cm^(-3) up to 110℃,showing a significant enhancement in thermal resistant properties and consequently outperforming most of the other ferroelectric polymers.Further microstructural investigations reveal that the improved thermal stability stems from the confinement effect on conformational motion of the crosslinking network,which is evidenced by the increased rigid amorphous fraction and steady intermolecular distance of amorphous regions from temperature-dependent X-ray diffraction results.Our findings provide a general and straightforward strategy to attain temperature-stable,high-energy-density polymer-based dielectrics for energy storage capacitors.展开更多
Organisms are capable of self-growth through the integration of the nutrients provided by the external environment.This process slows down when they grow.In this study,we mimicked this self-regulated growth via a simp...Organisms are capable of self-growth through the integration of the nutrients provided by the external environment.This process slows down when they grow.In this study,we mimicked this self-regulated growth via a simple swelling-polymerization strategy in which the stretching polymer chains in the original networks provide entropic elasticity to restrict growth in high growth cycles.Using typical covalently crosslinked polymers,such as acrylamide-based hydrogels and HBA-based elastomers,as examples,we demonstrate that the crosslinked polymers can absorb polymerizable compounds through a swelling-polymerization process to expand their sizes,but the growth extent becomes smaller with increasing growth cycle until reaching a plateau.In addition to their size,these materials become stiffer and exhibit less swelling ability in solvents.Our work not only provides a new growing mode to tune the properties of crosslinked polymers but also discloses the underlying mechanism of crosslinked polymers in multi-cyclic swelling conditions.展开更多
Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To...Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To achieve the desired properties of PI,the monomers 2,6-diaminopyrimidin-4-ol(DAPD)and 6-(2,3,5,6-tetrafluoro-4-vinylphenoxy)pyrimidin-2,4-diamine(DAFPD),which contains crosslinkable functional groups,were designed and synthesized successfully and copolymerized with 4,4'-oxydianiline(ODA)and 4,4-hexafluoroisopropylphthalic anhydride(6FDA).The prepared PI film(PI-3),with rigid backbones and loose packing had excellent heat resistance(Td5%=489℃)and optical properties(T450=82%).Furthermore,a crosslinked PI film(c-PI-3)with more heat-resistant(Td5%=524℃)and better mechanical properties(σ=125.46MPa),can be obtained through thermal crosslinking of tetrafluorostyrene.In addition,the changes in the properties caused by the proportion of DAFPD added during copolymerization are discussed comprehensively.This study provides a promising candidate for heat-resistant PI materials.展开更多
Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and ...Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and stretchability that align with biological tissues.Specifically,their materials should be capable of elastic strain up to 50–80%,while the devices themselves must maintain electric stability under strains that accommodate body movements[1].展开更多
Inorganic CsPbI_(3)perovskite with superior thermal stability and photoelectric properties has developed into a promising candidate for photovoltaic applications.Nevertheless,the power conversion efficiency(PCE)of CsP...Inorganic CsPbI_(3)perovskite with superior thermal stability and photoelectric properties has developed into a promising candidate for photovoltaic applications.Nevertheless,the power conversion efficiency(PCE)of CsPbI_(3)perovskite solar cells(PSCs)still lags far behind that of both organic-inorganic hybrid counterparts and the theoretical PCE limit,primarily restricted by severe fill factor(FF)and opencircuit voltage(VOC)deficits.Herein,an in-situ self-crosslinking strategy is proposed to construct high-performance inverted inorganic PSCs by incorporating acrylate monomers as additives into CsPbI_(3)perovskite precursors.During the thermal annealing process of perovskite films,acrylate monomers can form network structures by breaking the C=C groups through an in-situ polymerization reaction,mainly anchored at the grain boundaries(GBs)and on the surfaces of perovskite.Meanwhile,the C=O groups of acrylate polymers can favorably coordinate with uncoordinated Pb^(2+),thereby decreasing defect density and stabilizing the perovskite phase.Particularly,with multiple crosslinking and passivation sites,the incorporation of dipentaerythritol pentaacrylate(DPHA)can effectively improve the perovskite film quality,suppress nonradiative recombination,and block moisture erosion.Consequently,the DPHAbased PSC achieves a champion PCE of 20.05%with a record-high FF of 85.05%,both of which rank among the top in the performance of inverted CsPbI_(3)PSCs.Moreover,the unencapsulated DPHA-based device exhibits negligible hysteresis,remarkably improved long-term storage,and operational stability.This work offers a facile and useful strategy to simultaneously promote the efficiency and device stability of inverted inorganic PSCs.展开更多
Solid polymer electrolytes(SPEs)have attracted much attention for their safety,ease of packaging,costeffectiveness,excellent flexibility and stability.Poly-dioxolane(PDOL)is one of the most promising matrix materials ...Solid polymer electrolytes(SPEs)have attracted much attention for their safety,ease of packaging,costeffectiveness,excellent flexibility and stability.Poly-dioxolane(PDOL)is one of the most promising matrix materials of SPEs due to its remarkable compatibility with lithium metal anodes(LMAs)and suitability for in-situ polymerization.However,poor thermal stability,insufficient ionic conductivity and narrow electrochemical stability window(ESW)hinder its further application in lithium metal batteries(LMBs).To ameliorate these problems,we have successfully synthesized a polymerized-ionic-liquid(PIL)monomer named DIMTFSI by modifying DOL with imidazolium cation coupled with TFSI^(-)anion,which simultaneously inherits the lipophilicity of DOL,high ionic conductivity of imidazole,and excellent stability of PILs.Then the tridentate crosslinker trimethylolpropane tris[3-(2-methyl-1-aziridine)propionate](TTMAP)was introduced to regulate the excessive Li^(+)-O coordination and prepare a flame-retardant SPE(DT-SPE)with prominent thermal stability,wide ESW,high ionic conductivity and abundant Lit transference numbers(t_(Li+)).As a result,the LiFePO_(4)|DT-SPE|Li cell exhibits a high initial discharge specific capacity of 149.60 mAh g^(-1)at 0.2C and 30℃with a capacity retention rate of 98.68%after 500 cycles.This work provides new insights into the structural design of PIL-based electrolytes for long-cycling LMBs with high safety and stability.展开更多
All-safe liquid-state lithium-ion batteries(ASLS-LIBs) is of great interest as they can potentially combine the safety of all-solid-state batteries with the high performance and low manufacturing cost of traditional l...All-safe liquid-state lithium-ion batteries(ASLS-LIBs) is of great interest as they can potentially combine the safety of all-solid-state batteries with the high performance and low manufacturing cost of traditional liquid-state LIBs. However, the practical success of ASLS-LIBs is bottlenecked by the lack of advanced separator technology that can simultaneously realize high performances in puncturing-tolerability,fire-resistance, and importantly, wetting-capability with non-flammable liquid-electrolytes. Here, we propose a concept of inorganic in-situ separator(IISS) by hybrid-sol physical crosslinking directly onto the electrode surface to address the above challenges. Particularly, the hybrid-sol is designed with silica nanoparticles as the building block and poly(vinylidene difluoride) nanoparticles as the crosslinking agent. The critical factors for controlling the IISS microstructures and properties have been systematically investigated. The advantages of the IISS have been confirmed by its fast wetting with various fireresistant liquid-electrolytes, customizable thickness and porous structures, robust interface with planar or three-dimensional(3D)-structured electrodes, and importantly, unexpected self-adaptability against puncturing. Enabled by the above merits, a fire-resistant ASLS-LIB is successfully assembled and demonstrated with stable electrochemical performance. This sol-crosslinked IISS may open an avenue for the studies on the next-generation separator technology, cell assembling, solid electrolyte processing as well as non-flammable secondary batteries.展开更多
Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this e...Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.展开更多
AIM:To assess the visual outcomes and corneal biomechanical properties of myopia patients between laser in situ keratomileusis(LASIK)and LASIK combined with accelerated corneal crosslinking(LASIK Xtra).METHODS:This pr...AIM:To assess the visual outcomes and corneal biomechanical properties of myopia patients between laser in situ keratomileusis(LASIK)and LASIK combined with accelerated corneal crosslinking(LASIK Xtra).METHODS:This prospective study analyzed 52 consecutive myopia patients treated with LASIK Xtra and 45 consecutive myopia patients treated with LASIK.Only the right eyes in the two groups were analyzed.The uncorrected distance visual acuity(UDVA),keratometry values,postoperative central corneal thickness(CCT),corneal demarcation line depth,the corneal compensated intraocular pressure(IOPcc),Goldmann-correlated IOP(IOPg),corneal resistance factor(CRF)and corneal hysteresis(CH)from Ocular Response Analyzer(ORA)were analyzed.Further,the correlation between the demarcation line depth and ORA-related biomechanical parameters were analyzed.RESULTS:No significant differences in UDVA,postoperative CCT,or mean K values were found between the 2 groups at 1 to 12mo postoperative follow-up(all P>0.05).The changes of CRF was significantly lower in the LASIK Xtra group compared to the LASIK group(all P<0.05)at all the postoperative visits.The changes of CH were significantly higher in the LASIK Xtra group(all P<0.05).No significant differences were discovered regarding the changes of IOPcc and IOPg posperatively(all P>0.05).Out of 52 cases in the LASIK Xtra group,the demarcation line was present in 40 eyes(77%).The average depth of the demarcation was 220.73±42.70μm(136 to 288μm).No significant correlation was observed between the depth of the demarcation line and any of the ORA-related biomechanical parameters such as IOPcc,IOPg,CRF and CH at 12mo(all P>0.05).CONCLUSION:Both procedures demonstrate comparable outcomes in terms of visual acuity,refraction and ablation predictability.This study confirms that corneal biomechanical properties of the included patients weakened after both procedures,but the cornea after LASIK Xtra are stiffer than conventional LASIK.展开更多
Alginate is a natural polysaccharide polymer.Hydrogel filtration membranes prepared from alginate show excellent fouling resistance and controllable separation performance,but poor mechanical properties limit the use ...Alginate is a natural polysaccharide polymer.Hydrogel filtration membranes prepared from alginate show excellent fouling resistance and controllable separation performance,but poor mechanical properties limit the use of algae hydrogels.In this study,Ba^(2+)/Ca^(2+)co-crosslinked alginate(Ba/CaAlg)hydrogel membrane was prepared by cross-linking sodium alginate with a blend aqueous solution of barium ions and calcium ions,and the membrane was applied to the separation of dyes/salts from dyeing wastewater.Compared with the CaAlg membrane,the Ba/CaAlg hydrogel membrane exhibited more stable structure,and the mechanical properties and salt tolerance of the membrane were significantly improved.The flux of Ba/CaAlg membrane for methyl blue/sodium chloride mixed solution reached 43.5 L m^(−2) h^(−1),which was significantly higher than that of CaAlg membrane.Besides,the Ba/CaAlg membrane showed higher dye rejection(>99.6%)and lower salt rejection(<8.2%).The structure of Ba/CaAlg membrane was preliminarily simulated by molecular dynamics,and the pore size and distribution of the membrane were calculated.The Ba/CaAlg membrane has a broad application prospect in dyes/salts separation.展开更多
Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chain...Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.展开更多
As a type of bi-functional device,electrochromic supercapacitors(EC-SCs)have attracted extensive attention in diverse applications such as flexible electronics.However,despite recent encouraging progress,rational desi...As a type of bi-functional device,electrochromic supercapacitors(EC-SCs)have attracted extensive attention in diverse applications such as flexible electronics.However,despite recent encouraging progress,rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical applications.Here,we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of 3-fluorothiophene.The electrosynthesized free-standing poly(3-fluorothiophene)(PFT)films simultaneously achieve high electrochromic performance(optical contrast 42%at 560 nm with reversible color changes between purple and blue),and good capacitance property(290 F·g^(-1),1 A·g^(-1)),as well as outstanding cyclic stability(<2%reduction after 20000 cycles).We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices(FESDs),and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like bending.Such a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.展开更多
Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry.A sulfur-based lightly crosslinker can potentially enhance the self-h...Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry.A sulfur-based lightly crosslinker can potentially enhance the self-healing capabilities of rubber.Moreover,the rubber composites were studied for non-covalent interactions between the benzene rings of SBR and CB.In this research,rubber samples were prepared,and their structure was investigated using Fourier transform infrared (FTIR),and Raman spectroscopy.The red shift in Raman spectroscopy confirmed noncovalent interaction or hydrophobic interaction between SBR and CB in NR/SBR composites exposed to CB due to environmental change.The differential scanning calorimetry (DSC) thermograms showed that NR and SBR were incompatible.Additionally,the mechanical properties of these rubber blends were enhanced as the proportion of NR increased.The maximum self-healing performance reached 40%for the formulation containing 25 phr NR and 75 phr SBR,which also saved energy with low chain end movements.Therefore,these composites could be utilized as a semi-empirical model for studying crosslinked rubber blends,specifically in the rubber tire industry.展开更多
AIM:To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal crosslinking.METHODS:This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal cr...AIM:To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal crosslinking.METHODS:This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal crosslinking.The choroidal thicknesses were evaluated on enhanced depth imaging optical coherence tomography at the preoperative and postoperative 3d,1,and 3mo.Choroidal thickness in the four cardinal quadrants and the fovea were evaluated.The choroidal vascularity index was also calculated.RESULTS:There was no significant difference in central choroidal thickness between the preoperative and postoperative 3d,1mo(P>0.05).There was a significant increase in the 3mo(P=0.034)and a significant decrease in the horizontal choroidal vascularity index on the postoperative 3d(P=0.014),there was no statistically significant change in vertical axes and other visits in horizontal sections(P>0.05).CONCLUSION:This study sheds light on choroidal changes in postoperative corneal crosslinking for keratoconus.While it suggests the procedure’s relative safety for submacular choroid,more extensive research is necessary to confirm these findings and their clinical significance.展开更多
●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomi...●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis(FS-LASIK).●METHODS:A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo.The lenticules were collected from patients undertaking small incision lenticule extraction(SMILE)for the correction of myopia.Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength.●RESULTS:All surgeries were conducted successfully with no significant complications.Their best corrected visual acuity(BCVA)ranged from 0.05 to 0.8-2 before surgery.The pre-operational total corneal thickness ranged from 345-404μm and maximum keratometry(Kmax)ranged from 50.8 to 86.3.After the combination surgery,both the corneal keratometry(range 55.9 to 92.8)and total corneal thickness(range 413-482μm)significantly increased.Four out of 5 patients had improvement of corneal biomechanical parameters(reflected by stiffness parameter A1 in Corvis ST).However,3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze.Despite the onset of corneal edema right after SLAK,the corneal topography and thickness generally stabilized after 3mo.●CONCLUSION:SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia.Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22171182)Sichuan Tianfu Emei Plan.
文摘Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this study,novel poly(ε-caprolactone)(PCL)-poly(2-vinyl)ethylene glycol(PVEG)copolymers bearing multi-pendant vinyl groups is synthesized by branched-selective allylic etherification polymerization of vinylethylene carbonate(VEC)with linear and tetra-arm PCLs under a synergistic catalysis of palladium complex and boron reagent.Facile thiol-ene photo-click reaction of PCL-PVEG copolymers with multifunctional thiols can rapidly access a serious crosslinked SMPs with high shape memory performance.The thermal properties,mechanical properties and response temperature of the obtained SMPs are tunable by the variation of PCL prepolymers,vinyl contents and functionality of thiols.Moreover,high elastic modulus in the rubbery plateau region can be maintained effectively owing to high-density topological networks of the PCL materials.In addition,the utility of the present SMPs is further demonstrated by the post-functionalization via thiol-ene photo-click chemistry.
基金supported by the National Research Foundation(NRF)of Korea,funded by the Korean Government(MSIT)(Grant No.RS-2023-00240043).
文摘As the most abundant aromatic bio-based polymer,lignin has great potential as a sustainable feedstock for building crosslinked thermoset polymers as bio-based adhesives.However,the potential of hardwood kraft lignin(HKL)is limited due to its poor crosslinking reactivity.Hence,for the first time,the present study reports the facile oxidation of HKL involving a redox reaction with silver-ammonia complexes([(AgNH3)2]+),primarily focusing on oxidation to produce reactive quinones and promote C-C linkages during reaction.This study aims to increases reactivity of oxidized HKL for effective crosslinking with monoethanolamine(MEA)for the development of bio-based wood adhesives.The characterization,including 13C-nuclear magnetic resonance(NMR)and Fourier transform infrared(FT-IR)spectroscopy,confirms the oxidation reaction,such as the formation of quinones(C=O)and subsequent crosslinking between the oxidized HKL molecules and MEA.Additionally,gel permeation chromatography(GPC)confirms the C-C and C-O linkages with increased molecular weight after oxidation,and is supported by differential scanning calorimetry(DSC)which shows the exothermic reaction due to the crosslinking of the oxidized HKL molecules via condensation to form C-C and C-O linkages.The crosslinked HKL/MEA-based adhesives underwent mild reaction and achieved a maximum dry shear strength of 0.77 MPa,which exceeds the standard requirement of 0.6 MPa.These findings demonstrate not only a one-pot oxidation for improving the reactivity of HKL using silver complexes,but also its facile crosslinking with MEA for sustainable bio-based wood adhesives.
基金financially supported by the Natural Science Foundation of Shandong Province(Nos.ZR2021ME055,ZR2022QB170 and ZR2022MB034)the Foundation(No.GZKF202128)of State Key Laboratory of Biobased Material and Green Papermaking,Qilu University of Technology,Shandong Academy of Sciencesthe Development Program Project of Young Innovation Team of Institutions of Higher Learning in Shandong Province.
文摘It is urgent to develop high-performance polyimide(PI)films that simultaneously exhibit high transparency,exceptional thermal stability,mechanical robustness,and low dielectric to fulfil the requirements of flexible display technologies.Herein,a series of fluorinated polyimide films(FPIs)were fabricated by the condensation of 5,5′-(perfluoropropane-2,2-diyl)bis(isobenzofuran-1,3-dione)(6FDA)and the fluorinated triphenylmethane diamine monomer(EDA,MEDA and DMEDA)with heat-crosslinkable tetrafluorostyrene side groups,which was incorporated by different numbers of methyl groups pendant in the ortho position of amino groups.Subsequently,the FPI films underwent heating to produce crosslinking FPIs(C-FPIs)through the self-crosslinking of double bonds in the tetrafluorostyrene.The transparency,solvent resistance,thermal stability,mechanical robustness and dielectric properties of FPI and C-FPI films can be tuned by the number of methyl groups and crosslinking,which were deeply investigated by virtue of molecular dynamics(MD)simulations and density functional theory(DFT).As a result,all the films exhibited exceptional optically colorless and transparent,with transmittance in the visible region of 450-700 nm exceeding 79.9%,and the cut-off wavelengths(λ_(off))were nearly 350 nm.The thermal decomposition temperatures at 5% weight loss(T_(d5%))for all samples exceeded 504℃.These films exhibited a wide range of tunable tensile strength(46.5-75.1 MPa).Significantly,they showed exceptional dielectric properties with the dielectric constant of 2.3-2.5 at full frequency(10^(7)-20 Hz).This study not only highlights the relationship between the polymer molecular structure and properties,but offer insights for balancing optical transparency,heat resistance and low dielectric constant in PI films.
基金supported by Innovation Platform(Base)and Talent Special Project,Jilin Provincial Science&Technology Department,China(No.20230508033RC)。
文摘Heavy metal pollution poses serious risks to the human health and the natural environment,and there is an urgent need to develop efficient heavy metal removal technologies.The adsorption strategy is one of the most famous strategies for the capture of heavy metal ions.In recent years,hyper crosslinked polymers(HCPs),a kind of hyper crosslinked porous material prepared by Friedel-Crafts alkylation reaction,have attracted more and more attention because of their advantages of ultra-light framework,wide range of building monomers,easy modification and functionalization.This review focuses on the advances of HCPs in the efficient applications to the removal of heavy metal ions.The fundamentals are presented including physicochemical properties,adsorption mechanism,and preparation strategies.Subsequently,the application and influencing factors of HCPs toward heavy metal ion adsorption are discussed in detail.Furthermore,the opportunities and challenges of HCPs in this promising research field are summarized and anticipated.We are convinced that the advanced HCP-based materials will make further contributions to heavy metal removal in wastewater treatment,further paving the way of advancing researches in this field.
基金the support from National Natural Science Foundation of China(No.22161132006)Key R&D Program of Zhejiang(No.2024SSYS0036)Westlake University Startup。
文摘Reader proteins that bind specific methyllysine are important to biological functions of lysine methylation,but readers of many methyllysine sites are still unknown.Therefore,development of covalent probes is important to identify readers from cell samples so as to understand biological roles of lysine methylation.Generally,readers bind methyllysine via aromatic cages that contain tryptophan,tyrosine and phenylalanine,that offer a unique motif for selective crosslinking.We recently reported a site-selective tryptophan crosslinking strategy based on dimethylsulfonium that mimics dimethyllysine to crosslink tryptophan in aromatic cages of readers.Since tyrosine is a key residue for binding affinity to methyllysine,especially some readers that do not contain tryptophan residues in the binding pocket.Here we developed strategies of site-selective crosslinking to tyrosine.Ultraviolet(UV)source was applied to excite tyrosine at neutral pH or phenoxide at basic p H,and subsequent single-electron transfer(SET)from Tyr*to sulfonium inside the binding pocket enables selective crosslinking.In consequence,methyllysine readers with tyrosine-containing aromatic cages could be selectively crosslinked by site-specific sulfonium peptide probes.In addition,we expanded substrates from aromatic cages to tyrosine residues of proximate contact with sulfonium probes.The pair of LgBiT and SmBiT exhibited orthogonal crosslinking in complicated cell samples.As a result,we may expand sulfonium tools to target local tyrosine in future investigations.
基金supported by the National Natural Science Foundation of China(Grant No.52207031)the National Key R&D Program of China(Grant No.2020YFA0710500)。
文摘High-temperature performance of energy storage dielectric polymers is desired for many electronics and electrical applications,but the trade-off between energy density and temperature stability remains fundamentally challenging.Here,we report a general material design strategy to enhance energy storage performance at high temperatures by crosslinking a polar polymer and a high glass-transition temperature polymer as a crosslinked binary blend.Such crosslinked binary polymers display a temperature-insensitive and high energy density behavior of about6.2~8.5 J cm^(-3) up to 110℃,showing a significant enhancement in thermal resistant properties and consequently outperforming most of the other ferroelectric polymers.Further microstructural investigations reveal that the improved thermal stability stems from the confinement effect on conformational motion of the crosslinking network,which is evidenced by the increased rigid amorphous fraction and steady intermolecular distance of amorphous regions from temperature-dependent X-ray diffraction results.Our findings provide a general and straightforward strategy to attain temperature-stable,high-energy-density polymer-based dielectrics for energy storage capacitors.
基金financially supported by the National Natural Science Foundation of China(Nos.52203135 and 52273206)Postdoctoral Fellowship Program of CPSF(No.GZC20230372)+4 种基金Huzhou Science and Technology Program Projects(No.2023GZ18)Zhejiang Postdoctoral Research Project(No.ZJ2023133)Science and Technology Cooperation Fund Program of Chengdu-Chinese Academy of ScienceHunan Provincial Natural Science Foundation(No.2021JJ10029)Huxiang High-level Talent Gathering Project(No.2022RC4039)。
文摘Organisms are capable of self-growth through the integration of the nutrients provided by the external environment.This process slows down when they grow.In this study,we mimicked this self-regulated growth via a simple swelling-polymerization strategy in which the stretching polymer chains in the original networks provide entropic elasticity to restrict growth in high growth cycles.Using typical covalently crosslinked polymers,such as acrylamide-based hydrogels and HBA-based elastomers,as examples,we demonstrate that the crosslinked polymers can absorb polymerizable compounds through a swelling-polymerization process to expand their sizes,but the growth extent becomes smaller with increasing growth cycle until reaching a plateau.In addition to their size,these materials become stiffer and exhibit less swelling ability in solvents.Our work not only provides a new growing mode to tune the properties of crosslinked polymers but also discloses the underlying mechanism of crosslinked polymers in multi-cyclic swelling conditions.
基金supported by the National Key Research and Development Program of China(No.2022YFB3603101)。
文摘Polyimide(PI)is widely used in high-tech fields such as microelectronics,aerospace,and national defense because of its excellent optical properties,high-and low-temperature resistance,and good dimensional stability.To achieve the desired properties of PI,the monomers 2,6-diaminopyrimidin-4-ol(DAPD)and 6-(2,3,5,6-tetrafluoro-4-vinylphenoxy)pyrimidin-2,4-diamine(DAFPD),which contains crosslinkable functional groups,were designed and synthesized successfully and copolymerized with 4,4'-oxydianiline(ODA)and 4,4-hexafluoroisopropylphthalic anhydride(6FDA).The prepared PI film(PI-3),with rigid backbones and loose packing had excellent heat resistance(Td5%=489℃)and optical properties(T450=82%).Furthermore,a crosslinked PI film(c-PI-3)with more heat-resistant(Td5%=524℃)and better mechanical properties(σ=125.46MPa),can be obtained through thermal crosslinking of tetrafluorostyrene.In addition,the changes in the properties caused by the proportion of DAFPD added during copolymerization are discussed comprehensively.This study provides a promising candidate for heat-resistant PI materials.
基金supported by generous grants from the Natural Science Foundation of Zhejiang Province(LR24E030003)Zhejiang Province Qianjiang Talent Program(ZJ-QJRC-2020-32).
文摘Elastic electronics are increasingly prevalent in information storage,smart sensing and health monitoring due to their softness,stretchability and portability.Wearable electronic devices should possess elasticity and stretchability that align with biological tissues.Specifically,their materials should be capable of elastic strain up to 50–80%,while the devices themselves must maintain electric stability under strains that accommodate body movements[1].
基金supported by the Program for Science and Technology Innovation Team in Zhejiang(Grant No.2021R01004)the Natural Science Foundation of Ningbo City(No.2023J119)+1 种基金the Ningbo Youth Science and Technology Innovation Leading Talent Project(2023QL029)K.C.Wong Magna Fund in Ningbo University,China。
文摘Inorganic CsPbI_(3)perovskite with superior thermal stability and photoelectric properties has developed into a promising candidate for photovoltaic applications.Nevertheless,the power conversion efficiency(PCE)of CsPbI_(3)perovskite solar cells(PSCs)still lags far behind that of both organic-inorganic hybrid counterparts and the theoretical PCE limit,primarily restricted by severe fill factor(FF)and opencircuit voltage(VOC)deficits.Herein,an in-situ self-crosslinking strategy is proposed to construct high-performance inverted inorganic PSCs by incorporating acrylate monomers as additives into CsPbI_(3)perovskite precursors.During the thermal annealing process of perovskite films,acrylate monomers can form network structures by breaking the C=C groups through an in-situ polymerization reaction,mainly anchored at the grain boundaries(GBs)and on the surfaces of perovskite.Meanwhile,the C=O groups of acrylate polymers can favorably coordinate with uncoordinated Pb^(2+),thereby decreasing defect density and stabilizing the perovskite phase.Particularly,with multiple crosslinking and passivation sites,the incorporation of dipentaerythritol pentaacrylate(DPHA)can effectively improve the perovskite film quality,suppress nonradiative recombination,and block moisture erosion.Consequently,the DPHAbased PSC achieves a champion PCE of 20.05%with a record-high FF of 85.05%,both of which rank among the top in the performance of inverted CsPbI_(3)PSCs.Moreover,the unencapsulated DPHA-based device exhibits negligible hysteresis,remarkably improved long-term storage,and operational stability.This work offers a facile and useful strategy to simultaneously promote the efficiency and device stability of inverted inorganic PSCs.
基金financially supported by the National Key R&D Program of China(Grant No.2022YFE0207300)National Natural Science Foundation of China(Grant Nos.22179142 and 22075314)+1 种基金Jiangsu Funding Program for Excellent Postdoctoral Talent(Grant No.2024ZB051 and 2023ZB836)the technical support for Nano-X from Suzhou Institute of Nano-Tech and Nano-Bionics,Chinese Academy of Sciences(SINANO).
文摘Solid polymer electrolytes(SPEs)have attracted much attention for their safety,ease of packaging,costeffectiveness,excellent flexibility and stability.Poly-dioxolane(PDOL)is one of the most promising matrix materials of SPEs due to its remarkable compatibility with lithium metal anodes(LMAs)and suitability for in-situ polymerization.However,poor thermal stability,insufficient ionic conductivity and narrow electrochemical stability window(ESW)hinder its further application in lithium metal batteries(LMBs).To ameliorate these problems,we have successfully synthesized a polymerized-ionic-liquid(PIL)monomer named DIMTFSI by modifying DOL with imidazolium cation coupled with TFSI^(-)anion,which simultaneously inherits the lipophilicity of DOL,high ionic conductivity of imidazole,and excellent stability of PILs.Then the tridentate crosslinker trimethylolpropane tris[3-(2-methyl-1-aziridine)propionate](TTMAP)was introduced to regulate the excessive Li^(+)-O coordination and prepare a flame-retardant SPE(DT-SPE)with prominent thermal stability,wide ESW,high ionic conductivity and abundant Lit transference numbers(t_(Li+)).As a result,the LiFePO_(4)|DT-SPE|Li cell exhibits a high initial discharge specific capacity of 149.60 mAh g^(-1)at 0.2C and 30℃with a capacity retention rate of 98.68%after 500 cycles.This work provides new insights into the structural design of PIL-based electrolytes for long-cycling LMBs with high safety and stability.
基金National Natural Science Foundation of China (52203123)Sichuan Science and Technology Program (2023NSFSC0991)+2 种基金State Key Laboratory of Polymer Materials Engineering (sklpme-2023-1-05 and sklpme-2024-2-04)Fundamental Research Funds for the Central UniversitiesThis research was also partially sponsored by the Double First-Class Construction Funds of Sichuan University。
文摘All-safe liquid-state lithium-ion batteries(ASLS-LIBs) is of great interest as they can potentially combine the safety of all-solid-state batteries with the high performance and low manufacturing cost of traditional liquid-state LIBs. However, the practical success of ASLS-LIBs is bottlenecked by the lack of advanced separator technology that can simultaneously realize high performances in puncturing-tolerability,fire-resistance, and importantly, wetting-capability with non-flammable liquid-electrolytes. Here, we propose a concept of inorganic in-situ separator(IISS) by hybrid-sol physical crosslinking directly onto the electrode surface to address the above challenges. Particularly, the hybrid-sol is designed with silica nanoparticles as the building block and poly(vinylidene difluoride) nanoparticles as the crosslinking agent. The critical factors for controlling the IISS microstructures and properties have been systematically investigated. The advantages of the IISS have been confirmed by its fast wetting with various fireresistant liquid-electrolytes, customizable thickness and porous structures, robust interface with planar or three-dimensional(3D)-structured electrodes, and importantly, unexpected self-adaptability against puncturing. Enabled by the above merits, a fire-resistant ASLS-LIB is successfully assembled and demonstrated with stable electrochemical performance. This sol-crosslinked IISS may open an avenue for the studies on the next-generation separator technology, cell assembling, solid electrolyte processing as well as non-flammable secondary batteries.
基金support from Fonds de Recherche du Québec Santé(FRQS,grant no.281271)support from FRQS doctoral award #304367funding from CFI,Rheolution Inc.,and Investissement Québec.
文摘Xerostomia(dry mouth)is frequently experienced by patients treated with radiotherapy for head and neck cancers or with Sjögren’s syndrome,with no permanent cure existing for this debilitating condition.To this end,in vitro platforms are needed to test therapies directed at salivary(fluid-secreting)cells.However,since these are highly differentiated secretory cells,the maintenance of their differentiated state while expanding in numbers is challenging.In this study,the efficiency of three reversible thermo-ionically crosslinked gels:(1)alginate–gelatin(AG),(2)collagen-containing AG(AGC),and(3)hyaluronic acid-containing AG(AGHA),to recapitulate a native-like environment for human salivary gland(SG)cell expansion and 3D spheroid formation was compared.Although all gels were of mechanical properties comparable to human SG tissue(~11 kPa)and promoted the formation of 3D spheroids,AGHA gels produced larger(>100 cells/spheroid),viable(>93%),proliferative,and well-organized 3D SG spheroids while spatially and temporally maintaining the high expression of key SG proteins(aquaporin-5,NKCC1,ZO-1,α-amylase)for 14 days in culture.Moreover,the spheroids responded to agonist-induced stimulation by increasingα-amylase secretory granules.Here,we propose alternative lowcost,reproducible,and reversible AG-based 3D hydrogels that allow the facile and rapid retrieval of intact,highly viable 3D-SG spheroids.
基金Supported by Wu Jieping Medical Foundation(No.320.6750.2021-04-15).
文摘AIM:To assess the visual outcomes and corneal biomechanical properties of myopia patients between laser in situ keratomileusis(LASIK)and LASIK combined with accelerated corneal crosslinking(LASIK Xtra).METHODS:This prospective study analyzed 52 consecutive myopia patients treated with LASIK Xtra and 45 consecutive myopia patients treated with LASIK.Only the right eyes in the two groups were analyzed.The uncorrected distance visual acuity(UDVA),keratometry values,postoperative central corneal thickness(CCT),corneal demarcation line depth,the corneal compensated intraocular pressure(IOPcc),Goldmann-correlated IOP(IOPg),corneal resistance factor(CRF)and corneal hysteresis(CH)from Ocular Response Analyzer(ORA)were analyzed.Further,the correlation between the demarcation line depth and ORA-related biomechanical parameters were analyzed.RESULTS:No significant differences in UDVA,postoperative CCT,or mean K values were found between the 2 groups at 1 to 12mo postoperative follow-up(all P>0.05).The changes of CRF was significantly lower in the LASIK Xtra group compared to the LASIK group(all P<0.05)at all the postoperative visits.The changes of CH were significantly higher in the LASIK Xtra group(all P<0.05).No significant differences were discovered regarding the changes of IOPcc and IOPg posperatively(all P>0.05).Out of 52 cases in the LASIK Xtra group,the demarcation line was present in 40 eyes(77%).The average depth of the demarcation was 220.73±42.70μm(136 to 288μm).No significant correlation was observed between the depth of the demarcation line and any of the ORA-related biomechanical parameters such as IOPcc,IOPg,CRF and CH at 12mo(all P>0.05).CONCLUSION:Both procedures demonstrate comparable outcomes in terms of visual acuity,refraction and ablation predictability.This study confirms that corneal biomechanical properties of the included patients weakened after both procedures,but the cornea after LASIK Xtra are stiffer than conventional LASIK.
基金supported by the National Natural Science Foundation of China(No.22078244)Scientific research and development project of SINOPEC(No.222443)the Science and Technology Plans of Tianjin(No.20JCYBJC00120).
文摘Alginate is a natural polysaccharide polymer.Hydrogel filtration membranes prepared from alginate show excellent fouling resistance and controllable separation performance,but poor mechanical properties limit the use of algae hydrogels.In this study,Ba^(2+)/Ca^(2+)co-crosslinked alginate(Ba/CaAlg)hydrogel membrane was prepared by cross-linking sodium alginate with a blend aqueous solution of barium ions and calcium ions,and the membrane was applied to the separation of dyes/salts from dyeing wastewater.Compared with the CaAlg membrane,the Ba/CaAlg hydrogel membrane exhibited more stable structure,and the mechanical properties and salt tolerance of the membrane were significantly improved.The flux of Ba/CaAlg membrane for methyl blue/sodium chloride mixed solution reached 43.5 L m^(−2) h^(−1),which was significantly higher than that of CaAlg membrane.Besides,the Ba/CaAlg membrane showed higher dye rejection(>99.6%)and lower salt rejection(<8.2%).The structure of Ba/CaAlg membrane was preliminarily simulated by molecular dynamics,and the pore size and distribution of the membrane were calculated.The Ba/CaAlg membrane has a broad application prospect in dyes/salts separation.
基金financially supported by the Scientific Research Innovation Plan of Shanghai Education Commission (No. 2019-01-07-00-03-E00001)the National Natural Science Foundation of China (Nos. U21A2087 and 21975040)the Natural Science Foundation of Shanghai (No. 21ZR1400200)。
文摘Easy hydrolysis in alkaline environments limits the use of polyimide fibers in environmental protection. The hydrolysis resistance levels of polyimide fibers can be improved by crosslinking of the macromolecular chains. In this work, crosslinked polyimide fibers(CPI fibers) were produced by intrinsic carboxyl decarboxylation for the first time. The thermal stability of the polyimide fibers containing the intrinsic carboxyl groups(PIC fibers) was studied, and the temperature of the decarboxylation-crosslinking reaction was determined to be 450 ℃. The PIC fibers were hotdrawn to initiate thermal crosslinking of the carboxyl groups and molecular chain orientation at high temperature. The CPI fibers had high tensile strengths(0.72-1.46 GPa) and compressive strengths(401-604 MPa). The oriented macromolecules and chemically crosslinked structure improved the tightness of the molecular chains and endowed the CPI fibers with excellent hydrolytic resistance. The CPI-50 fiber did not dissolve in a 0.5 wt% NaOH solution during heating at 90 ℃ for 10 h, and the tensile strength retention reached 87% when treated in 0.5 wt% NaOH solutions at 90 ℃ for 1 h, providing a guarantee for its application in alkaline corrosive environments.
基金financially supported by the National Natural Science Foundation of China(Nos.52103214,52364039 and 51973102)Natural Science Foundation of Jiangxi Provincial(Nos.GJJ2201301 and 20232BAB202044)+4 种基金Natural Science Foundation of Shandong Province(Nos.ZR2022MB042 and ZR2019MB067)Innovation Ability Improvement Project ofScience and Technology Small and Medium-Size Enterprise in Shandong Province(No.2022TSGC1121)Qinghai Provincial Basic Research Program(No.2021-ZJ-710)Scientific Fund of Jiangxi Science&Technology Normal University(No.2022QNBJRC004)Talent Fund of QUST(2020)。
文摘As a type of bi-functional device,electrochromic supercapacitors(EC-SCs)have attracted extensive attention in diverse applications such as flexible electronics.However,despite recent encouraging progress,rational design and development of high-performance EC-SC materials with desirable stability remain challenging for practical applications.Here,we propose a fluorination strategy to develop high-performance EC-SC materials with tough hydrogen bonding cross-linked intermolecular polymer network by one-step electrosynthesis of 3-fluorothiophene.The electrosynthesized free-standing poly(3-fluorothiophene)(PFT)films simultaneously achieve high electrochromic performance(optical contrast 42%at 560 nm with reversible color changes between purple and blue),and good capacitance property(290 F·g^(-1),1 A·g^(-1)),as well as outstanding cyclic stability(<2%reduction after 20000 cycles).We further demonstrate the fabrication of PFT-based flexible electrochromic supercapacitor devices(FESDs),and the resultant devices can be used to visually monitor the energy storage state in real-time and maintain outstanding stability under mechanical distortion like bending.Such a tough fluorination hydrogen bonding cross-linking strategy may provide a new design concept for high-performance EC-SC materials and reliable FESDs toward practical applications.
基金supported by Budget Bureau, The Prime Minister’s Office, Thailand (the strategic program on value creation agriculture for Kasetsart University in the fiscal year 2024)。
文摘Crosslinking natural rubber (NR) and styrene butadiene rubber (SBR) composites with carbon black (CB) have been utilized in the tire tread industry.A sulfur-based lightly crosslinker can potentially enhance the self-healing capabilities of rubber.Moreover,the rubber composites were studied for non-covalent interactions between the benzene rings of SBR and CB.In this research,rubber samples were prepared,and their structure was investigated using Fourier transform infrared (FTIR),and Raman spectroscopy.The red shift in Raman spectroscopy confirmed noncovalent interaction or hydrophobic interaction between SBR and CB in NR/SBR composites exposed to CB due to environmental change.The differential scanning calorimetry (DSC) thermograms showed that NR and SBR were incompatible.Additionally,the mechanical properties of these rubber blends were enhanced as the proportion of NR increased.The maximum self-healing performance reached 40%for the formulation containing 25 phr NR and 75 phr SBR,which also saved energy with low chain end movements.Therefore,these composites could be utilized as a semi-empirical model for studying crosslinked rubber blends,specifically in the rubber tire industry.
文摘AIM:To investigate changes in choroidal thickness and vascularity in keratoconus patients treated with corneal crosslinking.METHODS:This study evaluated 28 eyes of 22 patients with keratoconus who underwent corneal crosslinking.The choroidal thicknesses were evaluated on enhanced depth imaging optical coherence tomography at the preoperative and postoperative 3d,1,and 3mo.Choroidal thickness in the four cardinal quadrants and the fovea were evaluated.The choroidal vascularity index was also calculated.RESULTS:There was no significant difference in central choroidal thickness between the preoperative and postoperative 3d,1mo(P>0.05).There was a significant increase in the 3mo(P=0.034)and a significant decrease in the horizontal choroidal vascularity index on the postoperative 3d(P=0.014),there was no statistically significant change in vertical axes and other visits in horizontal sections(P>0.05).CONCLUSION:This study sheds light on choroidal changes in postoperative corneal crosslinking for keratoconus.While it suggests the procedure’s relative safety for submacular choroid,more extensive research is necessary to confirm these findings and their clinical significance.
基金Supported by the Science&Technology Department of Sichuan Province(China)Funding Project(No.2021YFS0221,No.2023YFS0179)1.3.5 Project for Disciplines of Excellence,West China Hospital,Sichuan University(No.2022HXFH032,No.ZYJC21058)the Postdoctoral Research Funding of West China Hospital,Sichuan University,China(No.2020HXBH044).
文摘●AIM:To explore the clinical efficacy and safety of stromal lenticule addition keratoplasty(SLAK)with corneal crosslinking(CXL)on patients with corneal ectasia secondary to femtosecond laser-assisted in situ keratomileusis(FS-LASIK).●METHODS:A series of 5 patients undertaking SLAK with CXL for the treatment of corneal ectasia secondary to FS-LASIK were followed for 4-9mo.The lenticules were collected from patients undertaking small incision lenticule extraction(SMILE)for the correction of myopia.Adding a stromal lenticule was aimed at improving the corneal thickness for the safe application of crosslinking and compensating for the thin cornea to improve its mechanical strength.●RESULTS:All surgeries were conducted successfully with no significant complications.Their best corrected visual acuity(BCVA)ranged from 0.05 to 0.8-2 before surgery.The pre-operational total corneal thickness ranged from 345-404μm and maximum keratometry(Kmax)ranged from 50.8 to 86.3.After the combination surgery,both the corneal keratometry(range 55.9 to 92.8)and total corneal thickness(range 413-482μm)significantly increased.Four out of 5 patients had improvement of corneal biomechanical parameters(reflected by stiffness parameter A1 in Corvis ST).However,3 patients showed decreased BCVA after surgery due to the development of irregular astigmatism and transient haze.Despite the onset of corneal edema right after SLAK,the corneal topography and thickness generally stabilized after 3mo.●CONCLUSION:SLAK with CXL is a potentially beneficial and safe therapy for advanced corneal ectasia.Future work needs to address the poor predictability of corneal refractometry and compare the outcomes of different surgical modes.
