Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structu...Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies.展开更多
Ladder-like polyphenylsilsesquioxanes with fairly high regularity were synthesized using an endo-template 1,2-ethylenediamine at mild temperature via direct co-hydrolysis and condensation reactions in the presence of ...Ladder-like polyphenylsilsesquioxanes with fairly high regularity were synthesized using an endo-template 1,2-ethylenediamine at mild temperature via direct co-hydrolysis and condensation reactions in the presence of acid catalysts in the mixture of 1,4-dioxane/H20. The features for synthesis of ladder-like polyphenylsilsesquioxanes were investigated in detail. The products obtained were characterized by FTIR, SEC, XRD and NMR.展开更多
Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(dia...Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled onto CaF2 slide to form nanocomposite multilayers. Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy. IR spectrum suggests existence of OSi8 and PDDA in the LBL films. Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology.展开更多
Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-cappin...Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-capping＇ reaction.X-ray diffraction demonstrates that those two POSS have the similar T_8 structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.展开更多
The tetrameric neodymium-silsesquioxane cage complex,{[(i-C_4H_9)_7(Si_7O_(12))Nd])4NaCl},was prepared and used as precursor for the polymerization of isoprene.When activated by AlEt_3 in the presence of TMSCl,this PO...The tetrameric neodymium-silsesquioxane cage complex,{[(i-C_4H_9)_7(Si_7O_(12))Nd])4NaCl},was prepared and used as precursor for the polymerization of isoprene.When activated by AlEt_3 in the presence of TMSCl,this POSS-Nd complex (POSS=polyhedral oligomeric silsesquioxane) shows a moderate activity for the polymerization,and the effects of different ratios of Al/Nd,Cl/Nd and time on the polymerization were investigated.Moreover,The POSS-Nd complex may serve as models for the silica-supported rare earth cat...展开更多
Atomic oxygen （AO） found in low earth orbit can cause serious erosion to polyimide （PI） materials, which greatly limits their lifetime. 8-phenyl silsesquioxane （OPPOSS） was synthesized, and OPPOSS/PI composites ...Atomic oxygen （AO） found in low earth orbit can cause serious erosion to polyimide （PI） materials, which greatly limits their lifetime. 8-phenyl silsesquioxane （OPPOSS） was synthesized, and OPPOSS/PI composites were pre- pared by physical blending, followed by thermal imidization to enhance the AO erosion resistance of PI materials. The morphology, composition, and structure of the composites were analyzed before and after AO exposure in a ground sim- ulated facility of atomic oxygen. After 16 h AO exposure, the OPPOSS/PI composite with 5wt% OPPOSS addition shows an erosion rate of about 1.4×10-24 cm3/atom with only 48% mass loss of that of PI without OPPOSS addition. The mixture of OPPOSS nano molecules is assembled into a kind of regular square structure and distributed evenly in OPPOSS/PI composites. Some SiO2 particles are formed in the composites during AO exposure, which can act as ＂inert points＂ to reduce the AO erosion rate of OPPOSS/PI composites.展开更多
In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di...In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di（2-hydroxylpropylphenylether）]（3-aminopropyl） triethoxysilane （APES-PGE2, containing two hydroxyl groups）, were synthesized by reacting 1 mole of （3-aminopropyl）triethoxysilane （APES） with 2 mole of phenylglycidylether （PGE）. Then the hydrolytic condensation of APES-PGE and APES-PGE2 was performed by dissolving 1 g of the corresponding silane in 1.5 ml tetrahydrofuran （THF）, adding water and eventually a catalyst （molar ratios: [H2O]/Si=3, [NaOH]/Si=0.05）, and heating at 50 ℃ for 24 h, allowing continuous evaporation of volatiles. The final products with branches containing hydroxyl groups were polyhedral oligomeric silsesquioxanes （POSS）. The products from two reactions were characterized by standard spectroscopic techniques, gel partition chromatography （GPC）, Fourier-transformed infrared spectroscopy （FTIR） and matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry （UV-MALDI-TOF MS）. Additionally, a narrow mass distribution of multifunctionalized POSS was shown by UV-MALDI-TOF MS and assignments of the MS peaks.展开更多
Polyhedral oligomeric Silsesquioxanes (POSS) derived from vinyltrimethoxysilane (VMS) and modified with titanium tetrabutoxide (TTBO) (PVT) were prepared by sol-gel process catalyzed by hydrochloric acid (molar ratio:...Polyhedral oligomeric Silsesquioxanes (POSS) derived from vinyltrimethoxysilane (VMS) and modified with titanium tetrabutoxide (TTBO) (PVT) were prepared by sol-gel process catalyzed by hydrochloric acid (molar ratio: [HCl]/Si=0.05), and heating at 45 ℃ during 3 days. The PVT films (f-PVT) with different TTBO content, 5, 20 and 25wt% TTBO, were prepared by adding the stoichiometric amount of benzoyl peroxide (BPO) to PVT solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle and time. The hardness and elastic modulus of f-PVT were tested by continuous stiffness measurement (CSM) of nanoindentation, and the tribological behaviors were comparatively investigated with a nanoscratch test. The influence of the different TTBO contents on the mechanical properties of f-PVT was discussed. The scratch and friction coefficient profiles of f-PVT were illustrated. As the results of the test, f-PVT with 20% TTBO showed the better scratch resistance and tribological behavior.展开更多
The nonlinear optical （NLO） active chromophore was prepared bv a bridging agent, glyeidyl ether （ AGE）, to connect disperse orange 3 （ DO3 ） and （ γ-Methaerylpropyl）-silsesquioxane （MP-SSO）. A freeradical p...The nonlinear optical （NLO） active chromophore was prepared bv a bridging agent, glyeidyl ether （ AGE）, to connect disperse orange 3 （ DO3 ） and （ γ-Methaerylpropyl）-silsesquioxane （MP-SSO）. A freeradical polymerization was performed to fabricate the methacrylate/Silica hybrid NLO films. Different amounts （ 5-25 wt% ） of （γ-methacrylpropyl） -polyhedral oligomeric silsesquioxanes （POSS） were added as the modifier to improve the degree of cross-linking, density and structure of the NLO matrix. As a result, the modified material properties including coating transmittance, glass transition temperature （ Tg ） , absoption spectra before and after poling, Marker stripes, etc. were presented. The hybrid film containing 15 wt% POSS exhibits the highest T, nonresonant second-order nonlinearity （d33 = 92 pro/V） and temporal stability among the others.展开更多
In membrane distillation(MD),complicated feed water with amphiphilic contaminants induces fouling/wetting of the MD membrane and can even lead to process failure.This study reports a facile approach to fabricate robus...In membrane distillation(MD),complicated feed water with amphiphilic contaminants induces fouling/wetting of the MD membrane and can even lead to process failure.This study reports a facile approach to fabricate robust and self-healing hybrid amphiphobic membranes for anti-surfactant-wetting MD based on the ultra-low surface energy of fluorinated polyhedral oligomeric silsesquioxanes(F-POSS)and its thermal induced motivation and rotation.The thermal treatment makes the membranes achieving amphiphobicity at a very low cost of F-POSS(13.04 wt.%),which is about 1/3 of without thermal treatment.The prepared membrane exhibits excellent amphiphobicity,i.e.ethanol contact angle of 120.3°,without using environmentally toxic fluorinated nanoparticles.Robust MD performance was observed for the amphiphobic membrane in concentrated sodium dodecyl sulfate(SDS)feed solutions.Furthermore,the fabricated membrane exhibited stable amphiphobicity even in extreme environments,including strong acid or alkaline solutions.In the event of a damaged or abraded membrane surface where the F-POSS can be removed,the amphiphobic membrane exhibits self-healing ability with additional thermal treatment.This simple approach without the use of nanoparticles provides an environmentally friendly way for fabrication of amphiphobic membranes for anti-surfactant-wetting membrane distillation.展开更多
Herein, we present a novel way for the production of self-healing hydrogels with stretch beyond 4200% than their initial length and relatively high tensile strength （0.1-0.25 MPa）. Furthermore, the hydrogel was inse...Herein, we present a novel way for the production of self-healing hydrogels with stretch beyond 4200% than their initial length and relatively high tensile strength （0.1-0.25 MPa）. Furthermore, the hydrogel was insensitive to notch. Even for the samples containing V-notches, a stretch of 2300% was demonstrated. The hydrogels were developed by in situ crosslinking of the self-assembled colloidal poly（acrylic acid） （PAA）/functionalized polyhedral oligomeric silsesquioxane （POSS） micelles. This was achieved by the addition of functionalized polyhedral oligomeric silsesquioxane with tertiary amines and hydroxyls （POSS-AH） into the PAA reaction solution. The POSS-AH led to micellar growth, then the dual- crosslinked network was constructed. One type of crosslink was formed by hydrogen-bonding and ionic interactions between PAA chains and POSS-AH, the other type of crosslink was formed by covalent bonds between PAA and bis（N,N＇-methylene- bis-acrylamide）.展开更多
Octa（aminophenyl）silsesquioxane （OAPS） was used as the curing agent of diglycidyl ether of bisphenol-A （DGEBA） epoxy resin. A study on comparison of DGEBA/OAPS with DGEBA/4,4＇-diaminodiphenyl sulfone （DDS） ep...Octa（aminophenyl）silsesquioxane （OAPS） was used as the curing agent of diglycidyl ether of bisphenol-A （DGEBA） epoxy resin. A study on comparison of DGEBA/OAPS with DGEBA/4,4＇-diaminodiphenyl sulfone （DDS） epoxy resins was achieved. Differential scanning calorimetry was used to investigate the curing reaction and its kinetics, and the glass transition of DGEBA/OAPS. Thermogravimetric analysis was used to investigate thermal decomposition of the two kinds of epoxy resins. The reactions between amino groups and epoxy groups were investigated using Fourier transform infrared spectroscopy. Scanning electron microscopy was used to observe morphology of the two epoxy resins. The results indicated that OAPS had very good compatibility with DGEBA in molecular level, and could form a transparent DGEBA/OAPS resin. The curing reaction of the DGEBA/OAPS prepolymer could occur under low temperatures compared with DGEBA/DDS. The DGEBA/OAPS resin didn＇t exhibit glass transition, but the DGEBA/DDS did, which meant that the large cage structure of OAPS limited the motion of chains between the cross-linking points. Measurements of the contact angle indicated that the DGEBA/OAPS showed larger angles with water than the DGEBA/DDS resin. Thermogravimetric analysis indicated that the incorporation of OAPS into epoxy system resulted in low mass loss rate and high char yield, but its initial decomposition temperature seemed to be lowered.展开更多
4-（2-Ferrocenylethenyl）-phenyl-POSS Fc-CH=CH-C6H6-（C5H9）7Si8O12 （FEPS, Fc： ferrocene）, containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemi...4-（2-Ferrocenylethenyl）-phenyl-POSS Fc-CH=CH-C6H6-（C5H9）7Si8O12 （FEPS, Fc： ferrocene）, containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, ^1H-, ^13C and ^29Si- NMR.展开更多
A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly(styrene-co-maleic anhydride) (...A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly(styrene-co-maleic anhydride) (SMA). FT-IR spectroscopy confirmed the modification through introduction of peaks characteristic of ester linkages and carboxylic groups. The SMA/S-POSS hybrid membranes were fabricated from different S-POSS contents. The proton conductivity and methanol permeability of the hybrid membranes were studied with changing S-POSS content from 5wt.% to 30wt.%. It was found that the proton conductivity and the methanol permeability were dependent on the S-POSS content. Both of proton conductivity and methanol permeability properties improve with increasing S-POSS content. The proton conductivities of the hybrid membranes are in the range of 10-3-10-2 S·cm-1, and the range of methanol permeabilities was between 10-8 and 10-7 cm2·s-1. The membranes show good thermal properties characterized by thermogravimetric analysis (TGA).展开更多
Polyvinylcarbazole（PVK） composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane（POSS） PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole a...Polyvinylcarbazole（PVK） composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane（POSS） PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature（Tg） in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% （mass fraction）, while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.展开更多
Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the...Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.展开更多
Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octaphenyl silsesquioxane (OPS) in two steps, first nitration to obtain Octa(nitrophenyl)silsesquioxane (ONPS) then reduction by using the stable, inexpensive, ...Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octaphenyl silsesquioxane (OPS) in two steps, first nitration to obtain Octa(nitrophenyl)silsesquioxane (ONPS) then reduction by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent in the presence of Iron(III)Chloride catalyst with a yield of around 87%. Hydrazine is a two-electron reducing agent whereas nitro group is a four-electron reduction process. The activated carbon serves as an adsorbent and electrical conductor enabling the reaction to occur by acting as a mediator between a two-electron reagent and a four-electron process. Adsorption provides a reducing potential and a supply of electrons from many hydrazines making possible the initial four-electron process even though each individual hydrazine is a two-electron donor. The product was characterized by FTIR and 1H NMR. The time period for preparation of ONPS from octaphenyl silsesquioxane was considerably shortened to avoid double nitration of the aromatic rings.展开更多
Inorganic polyhedral oligomeric silsesquioxane （POSS） was used as the core for the synthesis of poly（t- lysine） peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite ...Inorganic polyhedral oligomeric silsesquioxane （POSS） was used as the core for the synthesis of poly（t- lysine） peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.展开更多
＂Click chemistry＂ is, by definition, a general functionalization methodology （GFM） and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis. This paper repor...＂Click chemistry＂ is, by definition, a general functionalization methodology （GFM） and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis. This paper reports the synthesis of a ＂clickable＂ middle-chain azide-functionalized polystyrene （mPS-N3） by anionic polymerization and its application in the preparation of novel shape amphiphiles based on polyhedral oligomeric silsesquioxane （POSS）. The mPS-N3 was synthesized by coupling living poly（styryl）lithium chains （PSLi） with 3-chloropropylmethyldichlorosilane and subsequent nucleophilic substitution of the chloro group in the presence of sodium azide. Excess PSLi was end-capped with ethylene oxide to facilitate its removal by flash chromatography. The raPS-N3 was then derived into a giant lipid-like shape amphiphile in two steps following a sequential ＂click＂ strategy. The copper（I）-catalyzed azide-alkyne cycloaddition between mPS-N3 and alkyne-functionalized vinyl-substituted POSS derivative （VPOSS-alkyne） ensured quantitative ligation to give polystyrene with VPOSS tethered at the middle of the chain （mPS-VPOSS）. The thiol-ene reaction with 1-thioglycerol transforms the vinyl groups on the POSS periphery to hydroxyls, resulting in an amphiphilic shape amphiphile, mPS-DPOSS. This synthetic approach is highly efficient and modular. It demonstrates the ＂click＂ philosophy of facile complex molecule construction from a library of simple building blocks and also suggests that mPS-N3 can be used as a versatile ＂clickable＂ motif in polymer science for the precise synthesis of complex macromolecules.展开更多
基金the National Natural Science Foundation of China(Nos.51603133 and 21774079)National Key R&D Program of China(No.2019YFA0904500)+1 种基金the Program of the Science,Technology Department of Guangzhou,China(No.201803020039)the Fundamental Research Funds for Central Universities.
文摘Although tremendous efforts have been devoted to the structural and functional tailoring of natural polyphenol-functionalized nan oparticles,preparing ultrasmall sized(<6 nm)particles with precisely-defined structures has remained a grand challenge.In this work,we reported the preparation of ultra-small and precisely structured polyhedral oligomeric silsesquioxanes(POSS)-based polyphenol nanopartides(T8^-,T10^-,and T12^-GAPOSS)by accurately functionalizing the POSS surface with plant polyphenol gallic acid units via thiol-Michael"click"reactions.Those polyphenol nanoparticles exhibited strong free radical scavenging capacity,good biocompatibility and ability to resist cell oxidative damage,which dem on strated great potentials in inhibiting oxidative stress in duced pathologies.
基金financially supported by the Zhejiang Provincial Natural Science Foundation(No.LY14E030008)the Commonweal Technology Application Research Project of Zhejiang Province(No.2013C31079)+1 种基金the National Natural Science Foundation of China(No.51353003)the China Postdoctoral Science Foundation(No.2013 M531455)
文摘Ladder-like polyphenylsilsesquioxanes with fairly high regularity were synthesized using an endo-template 1,2-ethylenediamine at mild temperature via direct co-hydrolysis and condensation reactions in the presence of acid catalysts in the mixture of 1,4-dioxane/H20. The features for synthesis of ladder-like polyphenylsilsesquioxanes were investigated in detail. The products obtained were characterized by FTIR, SEC, XRD and NMR.
文摘Layer-by-layer (LBL) self-assembly method was used to fabricate siliceous ultrathin films by using polyhedral oligomeric silsesquioxanes as building blocks. Ammonium salt of octasilsesquioxane acid (OSi8) and poly(diallyldimethylammonium chloride) (PDDA) were alternately assembled onto CaF2 slide to form nanocomposite multilayers. Linear build-up of the LBL films was confirmed by UV-Vis spectroscopy. IR spectrum suggests existence of OSi8 and PDDA in the LBL films. Atomic force microscopic surface topography of the LBL films indicates the OSi8 covers the entire surface of the topmost layer and shows a granular morphology.
基金the National Natural Science Foundation of China(No20772092)the Hubei Province Natural Science Fund for Distinguished Young Scholars(No2007ABB021) for financial support
文摘Two novel and well-defined polyhedral oligomeric silsesquioxanes（POSS） with two same Si_8O_（12） cores and a reactive NH group, namely bridged-POSS（2a and 2b）,have been prepared by the traditional ＇corner-capping＇ reaction.X-ray diffraction demonstrates that those two POSS have the similar T_8 structure.From the thermo-gravimetric analysis,bridged-POSS shows the belter thermal degradation stability than the contrastive POSS.
基金supported by the National Natural Science Foundation(No.20674071)the Special Funds for MajorState Basic Research Projects(No.2005CB623802).
文摘The tetrameric neodymium-silsesquioxane cage complex,{[(i-C_4H_9)_7(Si_7O_(12))Nd])4NaCl},was prepared and used as precursor for the polymerization of isoprene.When activated by AlEt_3 in the presence of TMSCl,this POSS-Nd complex (POSS=polyhedral oligomeric silsesquioxane) shows a moderate activity for the polymerization,and the effects of different ratios of Al/Nd,Cl/Nd and time on the polymerization were investigated.Moreover,The POSS-Nd complex may serve as models for the silica-supported rare earth cat...
基金fnancially supported by the National Natural Science Foundation of China(No.51206009)
文摘Atomic oxygen （AO） found in low earth orbit can cause serious erosion to polyimide （PI） materials, which greatly limits their lifetime. 8-phenyl silsesquioxane （OPPOSS） was synthesized, and OPPOSS/PI composites were pre- pared by physical blending, followed by thermal imidization to enhance the AO erosion resistance of PI materials. The morphology, composition, and structure of the composites were analyzed before and after AO exposure in a ground sim- ulated facility of atomic oxygen. After 16 h AO exposure, the OPPOSS/PI composite with 5wt% OPPOSS addition shows an erosion rate of about 1.4×10-24 cm3/atom with only 48% mass loss of that of PI without OPPOSS addition. The mixture of OPPOSS nano molecules is assembled into a kind of regular square structure and distributed evenly in OPPOSS/PI composites. Some SiO2 particles are formed in the composites during AO exposure, which can act as ＂inert points＂ to reduce the AO erosion rate of OPPOSS/PI composites.
文摘In the selected experimental conditions, firstly, the branched products with functional groups, N-（2-hydroxylpropylphenylether） （3-aminopropyl） triethoxysilane （APES-PGE, containing one hydroxyl group） and N-[di（2-hydroxylpropylphenylether）]（3-aminopropyl） triethoxysilane （APES-PGE2, containing two hydroxyl groups）, were synthesized by reacting 1 mole of （3-aminopropyl）triethoxysilane （APES） with 2 mole of phenylglycidylether （PGE）. Then the hydrolytic condensation of APES-PGE and APES-PGE2 was performed by dissolving 1 g of the corresponding silane in 1.5 ml tetrahydrofuran （THF）, adding water and eventually a catalyst （molar ratios: [H2O]/Si=3, [NaOH]/Si=0.05）, and heating at 50 ℃ for 24 h, allowing continuous evaporation of volatiles. The final products with branches containing hydroxyl groups were polyhedral oligomeric silsesquioxanes （POSS）. The products from two reactions were characterized by standard spectroscopic techniques, gel partition chromatography （GPC）, Fourier-transformed infrared spectroscopy （FTIR） and matrix-assisted ultraviolet laser desorption/ionization time-of-flight mass spectrometry （UV-MALDI-TOF MS）. Additionally, a narrow mass distribution of multifunctionalized POSS was shown by UV-MALDI-TOF MS and assignments of the MS peaks.
文摘Polyhedral oligomeric Silsesquioxanes (POSS) derived from vinyltrimethoxysilane (VMS) and modified with titanium tetrabutoxide (TTBO) (PVT) were prepared by sol-gel process catalyzed by hydrochloric acid (molar ratio: [HCl]/Si=0.05), and heating at 45 ℃ during 3 days. The PVT films (f-PVT) with different TTBO content, 5, 20 and 25wt% TTBO, were prepared by adding the stoichiometric amount of benzoyl peroxide (BPO) to PVT solutions in ethanol, dip-coating over glass substrates, and curing using an appropriate thermal cycle and time. The hardness and elastic modulus of f-PVT were tested by continuous stiffness measurement (CSM) of nanoindentation, and the tribological behaviors were comparatively investigated with a nanoscratch test. The influence of the different TTBO contents on the mechanical properties of f-PVT was discussed. The scratch and friction coefficient profiles of f-PVT were illustrated. As the results of the test, f-PVT with 20% TTBO showed the better scratch resistance and tribological behavior.
基金Sponsored by the Department of Science and Technology, the Government of Heilongjiang Province (Grant No.ZJG0506-02 and GB04A204).
文摘The nonlinear optical （NLO） active chromophore was prepared bv a bridging agent, glyeidyl ether （ AGE）, to connect disperse orange 3 （ DO3 ） and （ γ-Methaerylpropyl）-silsesquioxane （MP-SSO）. A freeradical polymerization was performed to fabricate the methacrylate/Silica hybrid NLO films. Different amounts （ 5-25 wt% ） of （γ-methacrylpropyl） -polyhedral oligomeric silsesquioxanes （POSS） were added as the modifier to improve the degree of cross-linking, density and structure of the NLO matrix. As a result, the modified material properties including coating transmittance, glass transition temperature （ Tg ） , absoption spectra before and after poling, Marker stripes, etc. were presented. The hybrid film containing 15 wt% POSS exhibits the highest T, nonresonant second-order nonlinearity （d33 = 92 pro/V） and temporal stability among the others.
基金the National Key Research and Development Program of China(No.2016YFB0600501)Natural Science Foundation of China(Nos.51425405 and 21377130)China Scholarship Council(No.201804910753)。
文摘In membrane distillation(MD),complicated feed water with amphiphilic contaminants induces fouling/wetting of the MD membrane and can even lead to process failure.This study reports a facile approach to fabricate robust and self-healing hybrid amphiphobic membranes for anti-surfactant-wetting MD based on the ultra-low surface energy of fluorinated polyhedral oligomeric silsesquioxanes(F-POSS)and its thermal induced motivation and rotation.The thermal treatment makes the membranes achieving amphiphobicity at a very low cost of F-POSS(13.04 wt.%),which is about 1/3 of without thermal treatment.The prepared membrane exhibits excellent amphiphobicity,i.e.ethanol contact angle of 120.3°,without using environmentally toxic fluorinated nanoparticles.Robust MD performance was observed for the amphiphobic membrane in concentrated sodium dodecyl sulfate(SDS)feed solutions.Furthermore,the fabricated membrane exhibited stable amphiphobicity even in extreme environments,including strong acid or alkaline solutions.In the event of a damaged or abraded membrane surface where the F-POSS can be removed,the amphiphobic membrane exhibits self-healing ability with additional thermal treatment.This simple approach without the use of nanoparticles provides an environmentally friendly way for fabrication of amphiphobic membranes for anti-surfactant-wetting membrane distillation.
基金financially supported by the Natural Science Foundation of Guangdong Province(No.2014A030313379)the National Natural Science Foundation of China(Nos.81171459 and 31400824)
文摘Herein, we present a novel way for the production of self-healing hydrogels with stretch beyond 4200% than their initial length and relatively high tensile strength （0.1-0.25 MPa）. Furthermore, the hydrogel was insensitive to notch. Even for the samples containing V-notches, a stretch of 2300% was demonstrated. The hydrogels were developed by in situ crosslinking of the self-assembled colloidal poly（acrylic acid） （PAA）/functionalized polyhedral oligomeric silsesquioxane （POSS） micelles. This was achieved by the addition of functionalized polyhedral oligomeric silsesquioxane with tertiary amines and hydroxyls （POSS-AH） into the PAA reaction solution. The POSS-AH led to micellar growth, then the dual- crosslinked network was constructed. One type of crosslink was formed by hydrogen-bonding and ionic interactions between PAA chains and POSS-AH, the other type of crosslink was formed by covalent bonds between PAA and bis（N,N＇-methylene- bis-acrylamide）.
文摘Octa（aminophenyl）silsesquioxane （OAPS） was used as the curing agent of diglycidyl ether of bisphenol-A （DGEBA） epoxy resin. A study on comparison of DGEBA/OAPS with DGEBA/4,4＇-diaminodiphenyl sulfone （DDS） epoxy resins was achieved. Differential scanning calorimetry was used to investigate the curing reaction and its kinetics, and the glass transition of DGEBA/OAPS. Thermogravimetric analysis was used to investigate thermal decomposition of the two kinds of epoxy resins. The reactions between amino groups and epoxy groups were investigated using Fourier transform infrared spectroscopy. Scanning electron microscopy was used to observe morphology of the two epoxy resins. The results indicated that OAPS had very good compatibility with DGEBA in molecular level, and could form a transparent DGEBA/OAPS resin. The curing reaction of the DGEBA/OAPS prepolymer could occur under low temperatures compared with DGEBA/DDS. The DGEBA/OAPS resin didn＇t exhibit glass transition, but the DGEBA/DDS did, which meant that the large cage structure of OAPS limited the motion of chains between the cross-linking points. Measurements of the contact angle indicated that the DGEBA/OAPS showed larger angles with water than the DGEBA/DDS resin. Thermogravimetric analysis indicated that the incorporation of OAPS into epoxy system resulted in low mass loss rate and high char yield, but its initial decomposition temperature seemed to be lowered.
基金We gratefully acknowledge the financial support of the National Natural Science Foundation of China(Project No.CN-20374007 and CN-50203002)Key Project of Science and Technology Foundation of Ministry of Education(03023).
文摘4-（2-Ferrocenylethenyl）-phenyl-POSS Fc-CH=CH-C6H6-（C5H9）7Si8O12 （FEPS, Fc： ferrocene）, containing metal and C=C double bond, was firstly synthesized as a mixture of E/Z isomers by the Wittig reaction. The chemical structure of FEPS was characterized by FTIR, ^1H-, ^13C and ^29Si- NMR.
文摘A novel sulfonated polyhedral oligomeric silsesquioxane(S-POSS) monomer was synthesized successfully in this article. S-POSS acted as a donor of sulfonic acid group and reacted with poly(styrene-co-maleic anhydride) (SMA). FT-IR spectroscopy confirmed the modification through introduction of peaks characteristic of ester linkages and carboxylic groups. The SMA/S-POSS hybrid membranes were fabricated from different S-POSS contents. The proton conductivity and methanol permeability of the hybrid membranes were studied with changing S-POSS content from 5wt.% to 30wt.%. It was found that the proton conductivity and the methanol permeability were dependent on the S-POSS content. Both of proton conductivity and methanol permeability properties improve with increasing S-POSS content. The proton conductivities of the hybrid membranes are in the range of 10-3-10-2 S·cm-1, and the range of methanol permeabilities was between 10-8 and 10-7 cm2·s-1. The membranes show good thermal properties characterized by thermogravimetric analysis (TGA).
基金Beijing Natural Science Foundation(No.2072015)the National High Technology Research and Development Program of China(No.2006AA032563).
文摘Polyvinylcarbazole（PVK） composites containing organic-inorganic hybrid polyhedral oligomeric silse-squioxane（POSS） PVK-POSS were prepared by free radical polymerization. POSS monomers reacted with vinylcarbazole and were completely dispersed at molecular level in PVK matrix and PVK-POSS nanocomposites display higher glass transition temperature（Tg） in comparison with neat PVK. Optical properties of PVK/POSS nanocomposites were investigated by UV-spectrum and PL-spectrum and the results show that the PVK-POSS nanoparticles have a good interface effect and improve color purity effectively. The maximum absorption wavelength bathochromically shifts gradually with the increasing of the content of POSS. The luminescent intensity becomes higher and higher with the increase of POSS content, and reaches its maximum luminescent intensity when the POSS content is 3% （mass fraction）, while some POSS-rich nanoparticles are present in matrix when contents of POSS are beyond 5%.
基金supported by the National Key Research and Development Program of China(Nos.2021YFA1601003,2017YFA0206002,2017YFA0403400)the National Natural Science Foundation of China(No.11775291)。
文摘Evaluating the comprehensive characteristics of extreme ultraviolet(EUV)photoresists is crucial for their application in EUV lithography,a key process in modern technology.This paper highlights the capabilities of the Shanghai Synchrotron Radiation Facility(SSRF)08U1B beamline in advancing this field.Specifically,it demonstrates how this beamline can create fringe patterns with a 15-nm half-pitch on a resist using synchrotron-based EUV lithography.This achievement is vital for evaluating EUV photoresists at the advanced 5-nm node.We provide a detailed introduction to the methods and experimental setup used at the SSRF 08U1B beamline to assess an EUV photoresist.A significant part of this research involved the fabrication of high-resolution hydrogen silsesquioxane mask gratings.These gratings,with an aspect ratio of approximately 3,were created using electron beam lithography on an innovative mask framework.This framework was crucial in eliminating the impact of zeroth-order light on interference patterns.The proposed framework propose offers a new approach to mask fabrication,particularly beneficial for achromatic Talbot lithography and multicoherent-beam interference applications.
文摘Octa(aminophenyl)silsesquioxane (OAPS) was prepared from octaphenyl silsesquioxane (OPS) in two steps, first nitration to obtain Octa(nitrophenyl)silsesquioxane (ONPS) then reduction by using the stable, inexpensive, and readily available hydrazine hydrate as the reducing agent in the presence of Iron(III)Chloride catalyst with a yield of around 87%. Hydrazine is a two-electron reducing agent whereas nitro group is a four-electron reduction process. The activated carbon serves as an adsorbent and electrical conductor enabling the reaction to occur by acting as a mediator between a two-electron reagent and a four-electron process. Adsorption provides a reducing potential and a supply of electrons from many hydrazines making possible the initial four-electron process even though each individual hydrazine is a two-electron donor. The product was characterized by FTIR and 1H NMR. The time period for preparation of ONPS from octaphenyl silsesquioxane was considerably shortened to avoid double nitration of the aromatic rings.
基金supported by the National Basic Research Program of China(National 973 program,No.2011CB606206)National Science Foundation of China(NSFC,Nos.31170921,51133004)+1 种基金the National Science Foundation for Excellent Young Scholars(No.51222304)Program for Changjiang Scholars and Innovative Research Team in University(No.IRT1163)
文摘Inorganic polyhedral oligomeric silsesquioxane （POSS） was used as the core for the synthesis of poly（t- lysine） peptide dendrimer via copper-catalyzed azide-alkyne click chemistry. The inorganic/organic composite dendrimer was characterized by MS, 1H NMR, FTIR, GPC and DLS.
文摘＂Click chemistry＂ is, by definition, a general functionalization methodology （GFM） and its marriage with living anionic polymerization is particularly powerful in precise macromolecular synthesis. This paper reports the synthesis of a ＂clickable＂ middle-chain azide-functionalized polystyrene （mPS-N3） by anionic polymerization and its application in the preparation of novel shape amphiphiles based on polyhedral oligomeric silsesquioxane （POSS）. The mPS-N3 was synthesized by coupling living poly（styryl）lithium chains （PSLi） with 3-chloropropylmethyldichlorosilane and subsequent nucleophilic substitution of the chloro group in the presence of sodium azide. Excess PSLi was end-capped with ethylene oxide to facilitate its removal by flash chromatography. The raPS-N3 was then derived into a giant lipid-like shape amphiphile in two steps following a sequential ＂click＂ strategy. The copper（I）-catalyzed azide-alkyne cycloaddition between mPS-N3 and alkyne-functionalized vinyl-substituted POSS derivative （VPOSS-alkyne） ensured quantitative ligation to give polystyrene with VPOSS tethered at the middle of the chain （mPS-VPOSS）. The thiol-ene reaction with 1-thioglycerol transforms the vinyl groups on the POSS periphery to hydroxyls, resulting in an amphiphilic shape amphiphile, mPS-DPOSS. This synthetic approach is highly efficient and modular. It demonstrates the ＂click＂ philosophy of facile complex molecule construction from a library of simple building blocks and also suggests that mPS-N3 can be used as a versatile ＂clickable＂ motif in polymer science for the precise synthesis of complex macromolecules.
