We improved the adhesion between silicon based insulating materials and epoxy resin composites by adding the adhesion promoter cycloborosiloxane(BSi,cyclo-1,3,3,5,7,7-hexaphenyl-1,5-diboro-3,7-disiloxane).The experime...We improved the adhesion between silicon based insulating materials and epoxy resin composites by adding the adhesion promoter cycloborosiloxane(BSi,cyclo-1,3,3,5,7,7-hexaphenyl-1,5-diboro-3,7-disiloxane).The experimental results show that the addition of BSi in the silicone rubber(SR)system significantly increases the tensile shear strength between BSi and epoxy resin(EP),reaching 309%of the original value.On this basis,the mechanism of BSi to enhance the adhesion effect was discussed.The electron deficient B in BSi attracted the electron rich N and O in EP to enhance the chemical interaction,combined with the interfacial migration behavior in the curing process,to improve the adhesion strength.This study provides the design and synthesis ideas of adhesive aids,and a reference for further exploring the interface mechanism of epoxy resin matrix composites.展开更多
Micro-sized silicon anodes have shown much promise in large-scale industrial production of high-energy lithium batteries.However,large volume change(>300%)of silicon anodes causes severe particle pulverization and ...Micro-sized silicon anodes have shown much promise in large-scale industrial production of high-energy lithium batteries.However,large volume change(>300%)of silicon anodes causes severe particle pulverization and the formation of unstable solid electrolyte interphases during cycling,leading to rapid capacity decay and short cycle life of lithium-ion batteries.When addressing such issues,binder plays key roles in obtaining good structural integrity of silicon anodes.Herein,we report a biopolymer composite binder composed of rigid poly(acrylic acid)(PAA)and flexible silk fibroin(SF)tailored for micro-sized silicon anodes.The PAA/SF binder shows robust gradient binding energy via chemical interactions between carboxyl and amide groups,which can effectively accommodate large volume change of silicon.This PAA/SF binder also shows much stronger adhesion force and improved binding towards high-surface/defective carbon additives,resulting in better electrochemical stability and higher coulombic efficiency,than conventional PAA binder.As such,micro-sized silicon/carbon anodes fabricated with novel PAA/SF binder exhibit much better cyclability(up to 500 cycles at 0.5 C)and enhanced rate capability compared with conventional PAA-based anodes.This work provides new insights into the design of functional binders for high-capacity electrodes suffering from large volume change for the development of nextgeneration lithium batteries.展开更多
Synthetic dry adhesives inspired by the nano-and micro-scale hairs found on the feet of geckos and some spiders have beendeveloped for almost a decade. Elastomeric single level micro-scale mushroom shaped fibres are c...Synthetic dry adhesives inspired by the nano-and micro-scale hairs found on the feet of geckos and some spiders have beendeveloped for almost a decade. Elastomeric single level micro-scale mushroom shaped fibres are currently able to function evenbetter than natural dry adhesives on smooth surfaces under normal loading. However, the adhesion of these single level syntheticdry adhesives on rough surfaces is still not optimal because of the reduced contact surface area. In nature, contact area ismaximized by hierarchically structuring different scales of fibres capable of conforming surface roughness. In this paper, weadapt the nature’s solution arid propose a novel dual-level hierarchical adhesive design using Polydimethylsiloxane (PDMS),which is tested under peel loading at different orientations. A negative macro-scale mold is manufactured by using a laser cutterto define holes in a Poly(methyl methacrylate) (PMMA) plate. After casting PDMS macro-scale fibres by using the obtainedPMMA mold, a previously prepared micro-fibre adhesive is bonded to the macro-scale fibre substrate. Once the bondingpolymer is cured, the micro-fibre adhesive is cut to form macro scale mushroom caps. Each macro-fibre of the resulting hierarchicaladhesive is able to conform to loads applied in different directions. The dual-level structure enhances the peel strengthon smooth surfaces compared to a single-level dry adhesive, but also weakens the shear strength of the adhesive for a given areain contact. The adhesive appears to be very performance sensitive to the specific size of the fibre tips, and experiments indicatethat designing hierarchical structures is not as simple as placing multiple scales of fibres on top of one another, but can requiresignificant design optimization to enhance the contact mechanics and adhesion strength.展开更多
AIM： To investigate the expression differences of transforming growth factor-β2（TGF-β2）, basic fibroblast growth factor（b FGF） and intercellular cell-adhesion molecule-1（ICAM-1） in lens epithelial cells（LECs...AIM： To investigate the expression differences of transforming growth factor-β2（TGF-β2）, basic fibroblast growth factor（b FGF） and intercellular cell-adhesion molecule-1（ICAM-1） in lens epithelial cells（LECs） of complicated cataract with silicone oil tamponade and agerelated cataract. METHODS： Totally 150 eyes of 150 patients（aged 35 to 77y） were investigated, including 75 patients with complicated cataract after silicone oil tamponade and 75 patients with age-related cataract. The central piece of anterior capsules was collected during cataract surgery. TGF-β2, b FGF and ICAM-1 were detected in the 60 specimens of the two groups by immunohistochemistry. The expression levels of the three kinds of messenger ribonucleic acid（m RNA） were determined by real-time quantitative reverse transcriptionpolymerase chain reaction in the 90 specimens of the two groups.RESULTS： TGF-β2 was detected in the cytomembrane and cytoplasm of the LECs and b FGF was detected in the nucleus. ICAM-1 was positive in the cytomembrane of the LECs and the distribution of positive cells was uneven. The m RNA genes expression of the TGF-β2, b FGF and ICAM-1 was significant differences between the two groups and markedly increased in complicated cataract group（P〈0.05）.CONCLUSION： The up-regulated TGF-β2, b FGF and ICAM-1 maybe associate with the occurrence and development of complicated cataract with silicone oil tamponade.展开更多
For improved wound healing,antimicrobial adhesives are one path forward.However,with the current challenge of bacterial resistance,it is essential to choose the included drug carefully.Octenidine is an obvious choice ...For improved wound healing,antimicrobial adhesives are one path forward.However,with the current challenge of bacterial resistance,it is essential to choose the included drug carefully.Octenidine is an obvious choice due to its broad antimicrobial efficacy and no reported bacterial resistance.In its pure form,octenidine complexes efficiently with the platinum catalyst in the silicone composition,inhibiting the targeted hydrosilyla-tion reaction and hindering curing.This obstacle is overcome by screening octenidine with cyclodextrins in homogeneously dispersed glycerol droplets,suppressing Pt inhibition in the silicone phase.Curing efficiency is demonstrated using rheol-ogy,which shows that it is possible to incorporate one wt%of octenidine into glycerol–silicone adhesives in the presence of(2-hydroxypropyl)-β-cyclodextrin without affecting the adhe-sives’mechanical properties.The interaction between octeni-dine and(2-hydroxypropyl)-β-cyclodextrin through an inclusion complex is confirmed by ROESY spectroscopy.Despite this screening,octenidine is still released efficiently from the glycerol–silicone adhesives upon contact with water,and the resulting antimicrobial action is subsequently demonstrated.This new technology constitutes a simple and efficient method for preparing wound care adhesives that actively inhibit the growth of four bacteria strains and one fungus.展开更多
基金the Core Research Facilities of College of Chemistry and Molecular Sciences and Wuhan University Test Center and Open Fund of Hubei Key Laboratory of Aerospace Power Advanced Technologythe Open Fund of Hubei Key Laboratory of Aerospace Power Advanced Technologythe Special Fund for Industrial and informatization Industry Foundation Reconstruction and High Quality Development of Manufacturing Industry(No.TC220H068)。
文摘We improved the adhesion between silicon based insulating materials and epoxy resin composites by adding the adhesion promoter cycloborosiloxane(BSi,cyclo-1,3,3,5,7,7-hexaphenyl-1,5-diboro-3,7-disiloxane).The experimental results show that the addition of BSi in the silicone rubber(SR)system significantly increases the tensile shear strength between BSi and epoxy resin(EP),reaching 309%of the original value.On this basis,the mechanism of BSi to enhance the adhesion effect was discussed.The electron deficient B in BSi attracted the electron rich N and O in EP to enhance the chemical interaction,combined with the interfacial migration behavior in the curing process,to improve the adhesion strength.This study provides the design and synthesis ideas of adhesive aids,and a reference for further exploring the interface mechanism of epoxy resin matrix composites.
文摘Micro-sized silicon anodes have shown much promise in large-scale industrial production of high-energy lithium batteries.However,large volume change(>300%)of silicon anodes causes severe particle pulverization and the formation of unstable solid electrolyte interphases during cycling,leading to rapid capacity decay and short cycle life of lithium-ion batteries.When addressing such issues,binder plays key roles in obtaining good structural integrity of silicon anodes.Herein,we report a biopolymer composite binder composed of rigid poly(acrylic acid)(PAA)and flexible silk fibroin(SF)tailored for micro-sized silicon anodes.The PAA/SF binder shows robust gradient binding energy via chemical interactions between carboxyl and amide groups,which can effectively accommodate large volume change of silicon.This PAA/SF binder also shows much stronger adhesion force and improved binding towards high-surface/defective carbon additives,resulting in better electrochemical stability and higher coulombic efficiency,than conventional PAA binder.As such,micro-sized silicon/carbon anodes fabricated with novel PAA/SF binder exhibit much better cyclability(up to 500 cycles at 0.5 C)and enhanced rate capability compared with conventional PAA-based anodes.This work provides new insights into the design of functional binders for high-capacity electrodes suffering from large volume change for the development of nextgeneration lithium batteries.
基金Finallcial support was provided by the Natural Sciences and Engineering Research Council of Canada(NSERC)the European Space Agency(ESA)
文摘Synthetic dry adhesives inspired by the nano-and micro-scale hairs found on the feet of geckos and some spiders have beendeveloped for almost a decade. Elastomeric single level micro-scale mushroom shaped fibres are currently able to function evenbetter than natural dry adhesives on smooth surfaces under normal loading. However, the adhesion of these single level syntheticdry adhesives on rough surfaces is still not optimal because of the reduced contact surface area. In nature, contact area ismaximized by hierarchically structuring different scales of fibres capable of conforming surface roughness. In this paper, weadapt the nature’s solution arid propose a novel dual-level hierarchical adhesive design using Polydimethylsiloxane (PDMS),which is tested under peel loading at different orientations. A negative macro-scale mold is manufactured by using a laser cutterto define holes in a Poly(methyl methacrylate) (PMMA) plate. After casting PDMS macro-scale fibres by using the obtainedPMMA mold, a previously prepared micro-fibre adhesive is bonded to the macro-scale fibre substrate. Once the bondingpolymer is cured, the micro-fibre adhesive is cut to form macro scale mushroom caps. Each macro-fibre of the resulting hierarchicaladhesive is able to conform to loads applied in different directions. The dual-level structure enhances the peel strengthon smooth surfaces compared to a single-level dry adhesive, but also weakens the shear strength of the adhesive for a given areain contact. The adhesive appears to be very performance sensitive to the specific size of the fibre tips, and experiments indicatethat designing hierarchical structures is not as simple as placing multiple scales of fibres on top of one another, but can requiresignificant design optimization to enhance the contact mechanics and adhesion strength.
基金Supported by the Natural Science Foundation of Shaanxi Province(No.2012JM4023)
文摘AIM： To investigate the expression differences of transforming growth factor-β2（TGF-β2）, basic fibroblast growth factor（b FGF） and intercellular cell-adhesion molecule-1（ICAM-1） in lens epithelial cells（LECs） of complicated cataract with silicone oil tamponade and agerelated cataract. METHODS： Totally 150 eyes of 150 patients（aged 35 to 77y） were investigated, including 75 patients with complicated cataract after silicone oil tamponade and 75 patients with age-related cataract. The central piece of anterior capsules was collected during cataract surgery. TGF-β2, b FGF and ICAM-1 were detected in the 60 specimens of the two groups by immunohistochemistry. The expression levels of the three kinds of messenger ribonucleic acid（m RNA） were determined by real-time quantitative reverse transcriptionpolymerase chain reaction in the 90 specimens of the two groups.RESULTS： TGF-β2 was detected in the cytomembrane and cytoplasm of the LECs and b FGF was detected in the nucleus. ICAM-1 was positive in the cytomembrane of the LECs and the distribution of positive cells was uneven. The m RNA genes expression of the TGF-β2, b FGF and ICAM-1 was significant differences between the two groups and markedly increased in complicated cataract group（P〈0.05）.CONCLUSION： The up-regulated TGF-β2, b FGF and ICAM-1 maybe associate with the occurrence and development of complicated cataract with silicone oil tamponade.
文摘For improved wound healing,antimicrobial adhesives are one path forward.However,with the current challenge of bacterial resistance,it is essential to choose the included drug carefully.Octenidine is an obvious choice due to its broad antimicrobial efficacy and no reported bacterial resistance.In its pure form,octenidine complexes efficiently with the platinum catalyst in the silicone composition,inhibiting the targeted hydrosilyla-tion reaction and hindering curing.This obstacle is overcome by screening octenidine with cyclodextrins in homogeneously dispersed glycerol droplets,suppressing Pt inhibition in the silicone phase.Curing efficiency is demonstrated using rheol-ogy,which shows that it is possible to incorporate one wt%of octenidine into glycerol–silicone adhesives in the presence of(2-hydroxypropyl)-β-cyclodextrin without affecting the adhe-sives’mechanical properties.The interaction between octeni-dine and(2-hydroxypropyl)-β-cyclodextrin through an inclusion complex is confirmed by ROESY spectroscopy.Despite this screening,octenidine is still released efficiently from the glycerol–silicone adhesives upon contact with water,and the resulting antimicrobial action is subsequently demonstrated.This new technology constitutes a simple and efficient method for preparing wound care adhesives that actively inhibit the growth of four bacteria strains and one fungus.
