Polyolefin-b-poly(ethylene oxide)(PEO)represents the most widely investigated amphiphilic block copolymers.So far,one-pot continuous synthesis of such hybrid block copolymers has only been fulfilled by anionic polymeriz...Polyolefin-b-poly(ethylene oxide)(PEO)represents the most widely investigated amphiphilic block copolymers.So far,one-pot continuous synthesis of such hybrid block copolymers has only been fulfilled by anionic polymerization through sequen-tial addition of vinyl monomers and ethylene oxide(EO).It still remains challenging to achieve altogether high block efficiency,high polymerization efficiency,and high molar mass for PEO.Here,we report a one-pot hybrid block copolymerization approach to polyisoprene/polystyrene(PI/PS)-b-PEO,in which PI/PS are formed by sBuLi-initiated anionic vinyl-addition polymerization,then in situ employed as macroinitiators for the anionic ring-opening polymerization(ROP)of EO aided by an organic Lewis pair.The cooperative(dual-ion-complexing)catalytic effect of organobase and triethylborane is proven,for thefirst time,effective for lithium alkoxide initiator system,allowing to achieve at room temperature high ROP activity(complete EO conversion and PEO of 3–64 kg/mol reached in 1–6 h),narrow molar mass distribution,controlled block lengths and composition.Density functional the-ory calculation shows that phosphazene bases are particularly effective,compared with N-heterocyclic bases,for complexing with Li+and enhancing the nucleophilic-ity of oxyanion.The rate of ROP is also affected by Li+-induced aggregation of the chain-end ion pairs,which though can be offset by adequate catalyst loadings.The versatility of this approach is further demonstrated in the one-pot synthesis of tri-/tetrablock ter-/quaterpolymers constituted by PI,PS,PEO,and poly(propylene oxide).Of great interest,PS-b-PI-b-PEO triblock terpolymer with a specific com-position is found to form internally microphase-separated micellar aggregates when dispersed in water.展开更多
We consider the inverse problem of finding guiding pattern shapes that result in desired self-assembly morphologies of block copolymer melts.Specifically,we model polymer selfassembly using the self-consistent field t...We consider the inverse problem of finding guiding pattern shapes that result in desired self-assembly morphologies of block copolymer melts.Specifically,we model polymer selfassembly using the self-consistent field theory and derive,in a non-parametric setting,the sensitivity of the dissimilarity between the desired and the actual morphologies to arbitrary perturbations in the guiding pattern shape.The sensitivity is then used for the optimization of the confining pattern shapes such that the dissimilarity between the desired and the actual morphologies is minimized.The efficiency and robustness of the proposed gradient-based algorithm are demonstrated in a number of examples related to templating vertical interconnect accesses(VIA).展开更多
Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein...Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.展开更多
A new kind of high performance composite resin matrix PEEK/PES, PEEKK/PES block copolymers have been prepared from the corresponding oligomers via a nucleophilic aromatic substitution reaction. The different propertie...A new kind of high performance composite resin matrix PEEK/PES, PEEKK/PES block copolymers have been prepared from the corresponding oligomers via a nucleophilic aromatic substitution reaction. The different properties of the copolymers are investigated by differential scanning calorimetry (d. s. c), thermogravimetric analysis (t. g. a) and dynamic mechanical analysis (d. m. a). The results show that the relationship between Tg and the compositions of the copolymers approximately follows the formula 1/Tg=W1/Tg1 +W2/Tg2 for PEEKK/PES block copolymers, and Tg=Tg1W1 +Tg2W2 for PEEK/PES block copolymers. The PES content and the segment length of the copolymers have a significant influence on their melting point. The thermal properties and dynamic mechanical behaviour of the copolymers are also studied. The introduction of PES segment into the molecular main chain increases the glass transition temperature of poly aryl ether ketones and decreases their melting temperature, that is to say it decreases their melting processing temperature. The block copolymers keep the high temperature stability and solvent resistance of poly aryl ether ketones. They are expected to be a new kind of high performance composite resin matrix.展开更多
A series of new amphiphilic poly[methyl（3,3,3-trifluoropropyl）siloxane]-b-poly（ethylene oxide） （PMTFPS-b-PEO） diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared ...A series of new amphiphilic poly[methyl（3,3,3-trifluoropropyl）siloxane]-b-poly（ethylene oxide） （PMTFPS-b-PEO） diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end-functlonal PMTFPS and PEO homopolymers. Copolymers were shown to be well defined and narrow molecular weight distribution （MWD） （1.07-1.3） by characterizations such as gel permeation chromatography （GPC） and ^1H-nudear magnetic resonance （^1H-NMR）.展开更多
Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure ...Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure and property of ESIS were characterized by Fourier transform infrared（FT-IR） spectroscopy,gel permeation chromatography（GPC）,thermogravimetric/differential thermogravimetric（TG/DTG）,melt flow rate（MFR） and dynamic mechanical analysis（DMA）,and the reaction mechanism in the process of epoxidation was analyzed.The results showed that C=C double bonds of 1,4-structure were more active than that of 3,4-structure in polyisoprene chains.With epoxidation reaction proceeding,the whole tendency of molecular weight increased and molecular weight distribution widened,and MFR firstly increased and latterly decreased.The heat resistance of ESIS was superior to that of SIS.When SIS was changed into ESIS with 15.3% of mass fraction of epoxide groups,Tg of polyisoprene chains increased from-45.3 ℃ to 10.9 ℃.In the earlier period of epoxidation,some molecular chains ruptured and new substances with low molecular weight formed.However,in the latter period,crosslinking reaction between molecular chains which was initiated by epoxide groups or C=C double bonds occurred and crosslinked insoluble substances came into being.展开更多
H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene ox...H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.展开更多
Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macr...Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.展开更多
The synthesis and characterization of amphiphilic copolymers of poly（dimethyl siloxane）(PDMS),poly（ethylene oxide）(PEO), and heparin（Hep） were investigated. These multiblock copolymers wereidentified using;H-NMR...The synthesis and characterization of amphiphilic copolymers of poly（dimethyl siloxane）(PDMS),poly（ethylene oxide）(PEO), and heparin（Hep） were investigated. These multiblock copolymers wereidentified using;H-NMR, FTIR, end group analysis, and sulfur elemental analysis. The multiblockcopolymers were characterized by using DSC and X-ray diffractometry. The glass transition temperature,crystalline melting characteristics, annealing effect, and cold crystallization of the block copolymers weredetermined by DSC. The crystallinity of the block copolymers was also determined by X-ray diffractionmethod.展开更多
The morphology of the film of polystyrene-block-poly（methyl methacrylate）（PS-b-PMMA） block copolymer having polystyrene（PS） cylinder forming composition spin-coated on a neutral brush modified silicon substrate ...The morphology of the film of polystyrene-block-poly（methyl methacrylate）（PS-b-PMMA） block copolymer having polystyrene（PS） cylinder forming composition spin-coated on a neutral brush modified silicon substrate has been investigated in this report. A mushroom-shaped morphology formed in the film with one period to two periods（L0--2L0） in thickness, which was spin-coated under a low humidity condition（RH ca.13%） and then thermally annealed at an extreme high temperature（230 ℃）. The results suggest that the spin-coating condition together with the confinement conditions plays a crucial role in the interesting morphology formation.展开更多
A series of H-shaped （PS）2PEG（PS）2 block copolymers with different PS chain lengths were prepared. The influence of different confinements active on the crystallization and self-nucleation （SN） behavior of the P...A series of H-shaped （PS）2PEG（PS）2 block copolymers with different PS chain lengths were prepared. The influence of different confinements active on the crystallization and self-nucleation （SN） behavior of the PEG blocks was investigated by differential scanning calorimetry （DSC）. When the content of the crystalline block was high, a classical SN behavior was obtained. The block copolymer with PEG content of 49% （by weight） showed a classical SN behavior with a narrow self-nucleation domain and had bimodal crystallization exotherms. When the PEG dispersed as separated microdomains in the block copolymer, the self-nucleation domain disappeared and only annealing was observed.展开更多
The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the co...The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the copolymer film. A kind of lamellae and an ordered bicontinuous double-diamond morphology are observed clearly. The lamellar morphology reveals a larger period of about 400 nm.展开更多
Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile...Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.展开更多
The design and synthesis of novel dendritic-linear block copolymers were described. The copolymers were synthesized by atom transfer radical polymerization (ATRP) using dendritic polyarylether 2-bromoisobutyrate macr...The design and synthesis of novel dendritic-linear block copolymers were described. The copolymers were synthesized by atom transfer radical polymerization (ATRP) using dendritic polyarylether 2-bromoisobutyrate macroinitiator. ATRP carried out in bulk with CuBr/bipy catalyst at 120癈, yielded well-defined block copolymers with polydispersities less than 1.36.展开更多
Novel double hydrophilic block copolymers with amine pendant chains were synthesized by polymerization of 4-vinyl benzylamine hydrochloric salt using 4,4′-azo-bis[4-cyanopentanoate poly（ethylene glycol） ester] as m...Novel double hydrophilic block copolymers with amine pendant chains were synthesized by polymerization of 4-vinyl benzylamine hydrochloric salt using 4,4′-azo-bis[4-cyanopentanoate poly（ethylene glycol） ester] as macroazoinitiator. The structures of the copolymers were characterized by ^1H NMR, FTIR spectra and acid-base titration, GPC-MALS techniques.展开更多
Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes a...Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.展开更多
Directed self-assembly(DSA)emerges as one of the most promising new patterning techniques for single digit miniaturization and next generation lithography.DSA achieves high-resolution patterning by molecular assembly ...Directed self-assembly(DSA)emerges as one of the most promising new patterning techniques for single digit miniaturization and next generation lithography.DSA achieves high-resolution patterning by molecular assembly that circumvents the diffraction limit of conventional photolithography.Recently,the International Roadmap for Devices and Systems listed DSA as one of the advanced lithography techniques for the fabrication of 3-5 nm technology node devices.DSA can be combined with other lithography techniques,such as extreme ultra violet(EUV)and 193 nm immersion(193i),to further enhance the patterning resolution and the device density.So far,DSA has demonstrated its superior ability for the fabrication of nanoscale devices,such as fin field effect transistor and bit pattern media,offering a variety of configurations for high-density integration and low-cost manufacturing.Over 1 T in-2 device density can be achieved either by direct templating or coupled with nanoimprinting to improve the throughput.The development of high x block copolymer further enhances the patterning resolution of DSA.In addition to its superiority in high-resolution patterning,the implementation ofDSA on a 300 mm pivot line fully demonstrates its potential for large-scale,high-throughput,and cost-effective manufacturing in industrial environment.展开更多
We investigated phase transitions in a diblock copolymer–homopolymer hybrid system blended with nanorods(NRs)by using the time-dependent Ginzburg–Landau theory.We systematically studied the effects of the number,len...We investigated phase transitions in a diblock copolymer–homopolymer hybrid system blended with nanorods(NRs)by using the time-dependent Ginzburg–Landau theory.We systematically studied the effects of the number,length and infiltration properties of the NRs on the self-assembly of the composites and the phase transitions occurring in the material.An analysis of the phase diagram was carried out to obtain the formation conditions of sea island structure nanorodbased aggregate,sea island structure nanorod-based dispersion,lamellar structure nanorod-based multilayer arrangement and nanowire structure.Further analysis of the evolution of the domain sizes and the distribution of the nanorod angle microphase structure was performed.Our simulation provides theoretical guidance for the preparation of ordered nanowire structures and a reference to improve the function of a polymer nanocomposite material.展开更多
The lithium-sulfur(Li-S)battery is one of the most promising substitutes for current energy storage systems because of its low cost,high theoretical capacity,and high energy density.However,the high solubility of inte...The lithium-sulfur(Li-S)battery is one of the most promising substitutes for current energy storage systems because of its low cost,high theoretical capacity,and high energy density.However,the high solubility of intermediate products(i.e.,lithium polysulfides)and the resultant shuttle effect lead to rapidly fading capacity and a low coulombic efficiency,which hinder the practical application of Li-S batteries.In this study,block copolymers are constructed with both an ethylene oxide unit and a styrene unit and then used as binders for Li-S batteries.Electrochemical performance improvements are attributed to the synergistic effects contributed by the different units of the block copolymer.The ethylene oxide unit traps polysulfide,which bonds strongly with the intermediate lithium polysulfide,and enhances the transport of lithium ions to reach high capacity.Meanwhile,the styrene unit maintains cathode integrity by improving the mechanical properties and elasticity of the constructed block copolymer to accommodate the large volume changes.By enabling multiple functions via different units in the polymer chain,high sulfur utilization is achieved,polysulfide diffusion is confined,and the shuttle effect is suppressed during the cycle life of Li-S batteries,as revealed by operando ultraviolet-visible spectroscopy and S Kedge X-ray absorption spectroscopy.展开更多
Fluorine substitution was applied to the donor and acceptor segments of block copolymers to understand the impact of molecular structure on photovoltaic block copolymers and explore efficient materials for single-comp...Fluorine substitution was applied to the donor and acceptor segments of block copolymers to understand the impact of molecular structure on photovoltaic block copolymers and explore efficient materials for single-component organic solar cells(SCOSCs).Along this line,three fluorinated block copolymers,namely PBDB-T-b-PTYF6,PM6-b-PTY6,and PM6-bPTYF6,derived from PBDB-T-b-PTY6 were designed and synthesized.The UV-Vis absorption,energy level,and thin-film morphology of these block copolymers were systematically characterized.All fluorinated block copolymers show narrow bandgap and improved crystallinity.An enhanced open-circuit voltage was observed in the SCOSC based on PM6-b-PTY6.However,SCOSCs based on all fluorinated block copolymers exhibited low short-circuit current due to energy level mismatch and therefore had low power conversion efficiency at around 4%.By contrast,the SCOSCs based on control block copolymer PBDB-T-b-PTY6 exhibited the highest power conversion efficiency approaching 10%,with a high short-circuit current of 18.57 mA/cm~2.Our study was the first to perform fluorination on photovoltaic block copolymers and provides insight into precisely controlling the polymer structure and understanding the structure-property relationship in SCOSCs based on block copolymers.展开更多
基金National Natural Science Foundation of China,Grant/Award Number:52022031Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates,Grant/Award Number:2023B1212060003Hunan Provincial Natural Science Foundation of China,Grant/Award Number:2023JJ40620。
文摘Polyolefin-b-poly(ethylene oxide)(PEO)represents the most widely investigated amphiphilic block copolymers.So far,one-pot continuous synthesis of such hybrid block copolymers has only been fulfilled by anionic polymerization through sequen-tial addition of vinyl monomers and ethylene oxide(EO).It still remains challenging to achieve altogether high block efficiency,high polymerization efficiency,and high molar mass for PEO.Here,we report a one-pot hybrid block copolymerization approach to polyisoprene/polystyrene(PI/PS)-b-PEO,in which PI/PS are formed by sBuLi-initiated anionic vinyl-addition polymerization,then in situ employed as macroinitiators for the anionic ring-opening polymerization(ROP)of EO aided by an organic Lewis pair.The cooperative(dual-ion-complexing)catalytic effect of organobase and triethylborane is proven,for thefirst time,effective for lithium alkoxide initiator system,allowing to achieve at room temperature high ROP activity(complete EO conversion and PEO of 3–64 kg/mol reached in 1–6 h),narrow molar mass distribution,controlled block lengths and composition.Density functional the-ory calculation shows that phosphazene bases are particularly effective,compared with N-heterocyclic bases,for complexing with Li+and enhancing the nucleophilic-ity of oxyanion.The rate of ROP is also affected by Li+-induced aggregation of the chain-end ion pairs,which though can be offset by adequate catalyst loadings.The versatility of this approach is further demonstrated in the one-pot synthesis of tri-/tetrablock ter-/quaterpolymers constituted by PI,PS,PEO,and poly(propylene oxide).Of great interest,PS-b-PI-b-PEO triblock terpolymer with a specific com-position is found to form internally microphase-separated micellar aggregates when dispersed in water.
文摘We consider the inverse problem of finding guiding pattern shapes that result in desired self-assembly morphologies of block copolymer melts.Specifically,we model polymer selfassembly using the self-consistent field theory and derive,in a non-parametric setting,the sensitivity of the dissimilarity between the desired and the actual morphologies to arbitrary perturbations in the guiding pattern shape.The sensitivity is then used for the optimization of the confining pattern shapes such that the dissimilarity between the desired and the actual morphologies is minimized.The efficiency and robustness of the proposed gradient-based algorithm are demonstrated in a number of examples related to templating vertical interconnect accesses(VIA).
基金Supported by the National Natural Science Foundation of China(21776126)the National Basic Research Program of China(2015CB655301)+1 种基金the Natural Science Foundation of Jiangsu Province(BK20150063)partially supported by the Open Fund of State Key Laboratory of Separation Membranes and Membrane Processes(M1-201702).
文摘Fouling resistance of ultrafiltration(UF) membranes is critical for their long-term usages in terms of stable performance, so convenient approaches to prepare fouling-resistant membranes are always anticipated. Herein, we demonstrate the facile fabrication of antifouling polysulfone-block-poly(ethylene glycol)(PSF-b-PEG, SFEG)composite membranes. SFEG layer was coated onto macroporous supports and cavitated by immerging them in acetone/n-propanol following the mechanism of selective swelling induced pore generation. Thus-produced SFEG membranes possessed high permeance and excellent mechanical strength. Meanwhile, the structures and separation performances of the SFEG layers can be continuously tuned through simply changing swelling durations. More importantly, the hydrophilic PEG chains were spontaneously enriched onto the pore walls through swelling treatment, endowing intrinsic antifouling property to the SFEG membranes. Bovine serum albumin(BSA)/humic acid(HA) fouling tests proved the prominent fouling resistance of SFEG membranes, and the fouling resistance is expected to be long-standing because of the firm connection between PEG chains and PSF matrix by covalent bonding.
文摘A new kind of high performance composite resin matrix PEEK/PES, PEEKK/PES block copolymers have been prepared from the corresponding oligomers via a nucleophilic aromatic substitution reaction. The different properties of the copolymers are investigated by differential scanning calorimetry (d. s. c), thermogravimetric analysis (t. g. a) and dynamic mechanical analysis (d. m. a). The results show that the relationship between Tg and the compositions of the copolymers approximately follows the formula 1/Tg=W1/Tg1 +W2/Tg2 for PEEKK/PES block copolymers, and Tg=Tg1W1 +Tg2W2 for PEEK/PES block copolymers. The PES content and the segment length of the copolymers have a significant influence on their melting point. The thermal properties and dynamic mechanical behaviour of the copolymers are also studied. The introduction of PES segment into the molecular main chain increases the glass transition temperature of poly aryl ether ketones and decreases their melting temperature, that is to say it decreases their melting processing temperature. The block copolymers keep the high temperature stability and solvent resistance of poly aryl ether ketones. They are expected to be a new kind of high performance composite resin matrix.
基金the National Natural Science Foundation of China (No. 20606029)the Postdoctoral Science Foundation of China (No. 20070420230)
文摘A series of new amphiphilic poly[methyl（3,3,3-trifluoropropyl）siloxane]-b-poly（ethylene oxide） （PMTFPS-b-PEO） diblock copolymers with different ratios of hydrophobic segment to hydrophilic segment were prepared by coupling reactions of end-functlonal PMTFPS and PEO homopolymers. Copolymers were shown to be well defined and narrow molecular weight distribution （MWD） （1.07-1.3） by characterizations such as gel permeation chromatography （GPC） and ^1H-nudear magnetic resonance （^1H-NMR）.
文摘Styrene-isoprene-styrene（SIS） block copolymer was modified into epoxidized styrene-isoprene-styrene（ESIS） block copolymer with performic acid generated in situ from hydrogen peroxide and formic acid.The structure and property of ESIS were characterized by Fourier transform infrared（FT-IR） spectroscopy,gel permeation chromatography（GPC）,thermogravimetric/differential thermogravimetric（TG/DTG）,melt flow rate（MFR） and dynamic mechanical analysis（DMA）,and the reaction mechanism in the process of epoxidation was analyzed.The results showed that C=C double bonds of 1,4-structure were more active than that of 3,4-structure in polyisoprene chains.With epoxidation reaction proceeding,the whole tendency of molecular weight increased and molecular weight distribution widened,and MFR firstly increased and latterly decreased.The heat resistance of ESIS was superior to that of SIS.When SIS was changed into ESIS with 15.3% of mass fraction of epoxide groups,Tg of polyisoprene chains increased from-45.3 ℃ to 10.9 ℃.In the earlier period of epoxidation,some molecular chains ruptured and new substances with low molecular weight formed.However,in the latter period,crosslinking reaction between molecular chains which was initiated by epoxide groups or C=C double bonds occurred and crosslinked insoluble substances came into being.
基金financial support from the National Natural Science Foundation of China(No.20134020)the Science Research Fund of the Chinese Ministry of Education(No.104005)the Science Research Fund of Shandong Provincial Education Department of China(No.105D11).
文摘H-type amphiphilic liquid crystalline block copolymers containing azobenzene were synthesized by atom transfer radical polymerization （ATRP）. Macroinitiators prepared by the esterification between poly（ethylene oxide） （PEG） and 2,2-dichloroacetyl chloride were utilized to initiate the polymerization of 6-[4-（4-ethoxyphenylazo）phenoxy]hexyl rnethacrylate （M6C）. The resulting macroinitiators and block copolymers were characterized by ^1H NMR, gel permeation chromatography （GPC）. Polarizing optical microscopy （POM） and differential scanning calorimetry （DSC） preliminarily revealed the liquid crystalline property of these block copolymers. This series of liquid crystalline block copolymers are promising in some areas, such as optical data storage, optical switch, and molecular devices.
基金support from the National Natural Science Foundation of China(No. 20134020)the Visiting Scholar Project of Shandong Province of China(No.20081001)the Science Research Fund of Shandong Jiaotong University of China(No.Z200802)
文摘Novel Y-shaped block copolymers of poly（ethylene glycol） and poly（N-isopropylacrylamide）, PEG-b-（PNIPAM）2, were successfully synthesized through atom transfer radical polymerization （ATRP）. A difunctional macroinitiator was prepared by esterification of 2,2-dichloroacetyl chloride with poly（ethylene glycol） monomethyl ether （PEG）. The copolymers were obtained via the ATRP ofN-isopropylacrylamide （NIPAM） at 30℃ with CuCl/Me6TREN as a catalyst system and DMF/H2O （v/v = 3：1） mixture as solvent. The resulting copolymers were characterized by gel permeation chromatography （GPC） and ^1H NMR. These block copolymers show controllable molecular weights and narrow molecular weight distributions （PDI 〈 1.15）. Their phase transition temperatures and the corresponding enthalpy changes in aqueous solution were measured by differential scanning calorimetry （DSC）. As a result, the phase transition temperature of PEG45-b-（PNIPAM55）2 is higher than that of PNIPAM, however, the corresponding enthalpy change is much lower, indicating the significant influence of the macromolecular composition and architecture on the phase transition.
文摘The synthesis and characterization of amphiphilic copolymers of poly（dimethyl siloxane）(PDMS),poly（ethylene oxide）(PEO), and heparin（Hep） were investigated. These multiblock copolymers wereidentified using;H-NMR, FTIR, end group analysis, and sulfur elemental analysis. The multiblockcopolymers were characterized by using DSC and X-ray diffractometry. The glass transition temperature,crystalline melting characteristics, annealing effect, and cold crystallization of the block copolymers weredetermined by DSC. The crystallinity of the block copolymers was also determined by X-ray diffractionmethod.
基金Supported by the Liaoning Provincial Foundation for Doctors(China)(No910502)
文摘The morphology of the film of polystyrene-block-poly（methyl methacrylate）（PS-b-PMMA） block copolymer having polystyrene（PS） cylinder forming composition spin-coated on a neutral brush modified silicon substrate has been investigated in this report. A mushroom-shaped morphology formed in the film with one period to two periods（L0--2L0） in thickness, which was spin-coated under a low humidity condition（RH ca.13%） and then thermally annealed at an extreme high temperature（230 ℃）. The results suggest that the spin-coating condition together with the confinement conditions plays a crucial role in the interesting morphology formation.
基金supported by the National Natural Science Foundation of China(No.50503022)Programs and the Fund for Creative Research Groups(No.50621302)
文摘A series of H-shaped （PS）2PEG（PS）2 block copolymers with different PS chain lengths were prepared. The influence of different confinements active on the crystallization and self-nucleation （SN） behavior of the PEG blocks was investigated by differential scanning calorimetry （DSC）. When the content of the crystalline block was high, a classical SN behavior was obtained. The block copolymer with PEG content of 49% （by weight） showed a classical SN behavior with a narrow self-nucleation domain and had bimodal crystallization exotherms. When the PEG dispersed as separated microdomains in the block copolymer, the self-nucleation domain disappeared and only annealing was observed.
文摘The phase behavior of a well-defined poly(methyl methacrylate)- b- polystyrene block copolymer was studied by transmission electron microscope. The results show that a microphase transition may have occurred in the copolymer film. A kind of lamellae and an ordered bicontinuous double-diamond morphology are observed clearly. The lamellar morphology reveals a larger period of about 400 nm.
文摘Block copolymers with different backbone compositions have been prepared by the condensation of dimethylamino terminated poly（dimethylsiloxane） （PDMS） and hydroquinone terminated poly（phthalazinone ether nitrile） （PPEN） in the presence of chlorobenzcne/N-methyl pyrrolidone （NMP） as solvents. The products were characterized by FTIR, ^1H NMR and gel permeation chromatography. Differential scanning calorimetry analysis indicated that the block copolymers showed separated microphase.
文摘The design and synthesis of novel dendritic-linear block copolymers were described. The copolymers were synthesized by atom transfer radical polymerization (ATRP) using dendritic polyarylether 2-bromoisobutyrate macroinitiator. ATRP carried out in bulk with CuBr/bipy catalyst at 120癈, yielded well-defined block copolymers with polydispersities less than 1.36.
文摘Novel double hydrophilic block copolymers with amine pendant chains were synthesized by polymerization of 4-vinyl benzylamine hydrochloric salt using 4,4′-azo-bis[4-cyanopentanoate poly（ethylene glycol） ester] as macroazoinitiator. The structures of the copolymers were characterized by ^1H NMR, FTIR spectra and acid-base titration, GPC-MALS techniques.
基金supported financially by the National Key R&D Program of China (Grant No. 2018YFB0104300)Beijing Natural Science Foundation (JQ19003, KZ201910005002 and L182009)+1 种基金National Natural Science Foundation of China (Grants 21875007, 51622202, and 21974007)the Project of Youth Talent Plan of Beijing Municipal Education Commission (CIT&TCD201804013)。
文摘Solid polymer electrolytes have been considered as the promising candidates to improve the safety and stability of high-energy lithium metal batteries.However,the practical applications of solid polymer electrolytes are still limited by the low ionic conductivity,poor interfacial contact with electrodes,narrow electrochemical window and weak mechanical strength.Here,a series of novel block copolymer electrolytes with three-dimensional networks are designed by cross-linked copolymerization of the polyethylene glycol soft segments and hexamethylene diisocyanate trimer hard segments.Their ionic migration performances and interface compatibilities with Li metal anode have been optimized delicately by tailoring the ratio of these functional units.The optimized block copolymer electrolyte has shown an amorphous crystalline structure,a high ionic conductivity of ~5.7×10^(-4)S cm^(-1),high lithium ion transference number(~0.49),wide electrochemical window up to ~4.65 V(vs.Li+/Li) and favorable mechanical strength at 55℃.Furthermore,the enhanced interface compatibility can well support the normal operations of lithium metal batteries using both LiFePO4 and LiNi0.8Co0.15Al0.05O2 cathodes.This study not only paves a new way to develop solid polymer electrolyte with optimizing functional units,but also provides a polymer electrolyte design strategy for the application demand of lithium metal battery.
文摘Directed self-assembly(DSA)emerges as one of the most promising new patterning techniques for single digit miniaturization and next generation lithography.DSA achieves high-resolution patterning by molecular assembly that circumvents the diffraction limit of conventional photolithography.Recently,the International Roadmap for Devices and Systems listed DSA as one of the advanced lithography techniques for the fabrication of 3-5 nm technology node devices.DSA can be combined with other lithography techniques,such as extreme ultra violet(EUV)and 193 nm immersion(193i),to further enhance the patterning resolution and the device density.So far,DSA has demonstrated its superior ability for the fabrication of nanoscale devices,such as fin field effect transistor and bit pattern media,offering a variety of configurations for high-density integration and low-cost manufacturing.Over 1 T in-2 device density can be achieved either by direct templating or coupled with nanoimprinting to improve the throughput.The development of high x block copolymer further enhances the patterning resolution of DSA.In addition to its superiority in high-resolution patterning,the implementation ofDSA on a 300 mm pivot line fully demonstrates its potential for large-scale,high-throughput,and cost-effective manufacturing in industrial environment.
基金Project supported by the National Natural Science Foundation of China(Grant No.21373131)the Provincial Natural Science Foundation of Shanxi,China(Grant No.2015011004)the Research Foundation for Excellent Talents of Shanxi Provincial Department of Human Resources and Social Security,China
文摘We investigated phase transitions in a diblock copolymer–homopolymer hybrid system blended with nanorods(NRs)by using the time-dependent Ginzburg–Landau theory.We systematically studied the effects of the number,length and infiltration properties of the NRs on the self-assembly of the composites and the phase transitions occurring in the material.An analysis of the phase diagram was carried out to obtain the formation conditions of sea island structure nanorodbased aggregate,sea island structure nanorod-based dispersion,lamellar structure nanorod-based multilayer arrangement and nanowire structure.Further analysis of the evolution of the domain sizes and the distribution of the nanorod angle microphase structure was performed.Our simulation provides theoretical guidance for the preparation of ordered nanowire structures and a reference to improve the function of a polymer nanocomposite material.
基金supported by the Assistant Secretary for Energy Efficiency and Renewable Energy,Vehicle Technologies Office,under the Advanced Battery Materials Research(BMR)Program of the U.S.Department of Energy under Contract No.DE-AC02-05CH11231support by the U.S.Department of Energy under Contract No.106298-001+2 种基金the funding from Polish Ministry of Science and Higher Education No.1670/MOB/V/2017/0funding support of SUSTechthe resources of the National Energy Research Scientific Computing Center(NERSC)that is supported by the Office of Science of the U.S.Department of Energy。
文摘The lithium-sulfur(Li-S)battery is one of the most promising substitutes for current energy storage systems because of its low cost,high theoretical capacity,and high energy density.However,the high solubility of intermediate products(i.e.,lithium polysulfides)and the resultant shuttle effect lead to rapidly fading capacity and a low coulombic efficiency,which hinder the practical application of Li-S batteries.In this study,block copolymers are constructed with both an ethylene oxide unit and a styrene unit and then used as binders for Li-S batteries.Electrochemical performance improvements are attributed to the synergistic effects contributed by the different units of the block copolymer.The ethylene oxide unit traps polysulfide,which bonds strongly with the intermediate lithium polysulfide,and enhances the transport of lithium ions to reach high capacity.Meanwhile,the styrene unit maintains cathode integrity by improving the mechanical properties and elasticity of the constructed block copolymer to accommodate the large volume changes.By enabling multiple functions via different units in the polymer chain,high sulfur utilization is achieved,polysulfide diffusion is confined,and the shuttle effect is suppressed during the cycle life of Li-S batteries,as revealed by operando ultraviolet-visible spectroscopy and S Kedge X-ray absorption spectroscopy.
基金supported by the National Natural Science Foundation of China(No.52073198)Science Foundation of Jiangsu Province(BK20211598)+1 种基金“111”project,the China Postdoctoral Science Foundation(No.2021T140495),Collaborative Innovation Center of Suzhou Nano Science and Technology,Soochow Universitythe Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘Fluorine substitution was applied to the donor and acceptor segments of block copolymers to understand the impact of molecular structure on photovoltaic block copolymers and explore efficient materials for single-component organic solar cells(SCOSCs).Along this line,three fluorinated block copolymers,namely PBDB-T-b-PTYF6,PM6-b-PTY6,and PM6-bPTYF6,derived from PBDB-T-b-PTY6 were designed and synthesized.The UV-Vis absorption,energy level,and thin-film morphology of these block copolymers were systematically characterized.All fluorinated block copolymers show narrow bandgap and improved crystallinity.An enhanced open-circuit voltage was observed in the SCOSC based on PM6-b-PTY6.However,SCOSCs based on all fluorinated block copolymers exhibited low short-circuit current due to energy level mismatch and therefore had low power conversion efficiency at around 4%.By contrast,the SCOSCs based on control block copolymer PBDB-T-b-PTY6 exhibited the highest power conversion efficiency approaching 10%,with a high short-circuit current of 18.57 mA/cm~2.Our study was the first to perform fluorination on photovoltaic block copolymers and provides insight into precisely controlling the polymer structure and understanding the structure-property relationship in SCOSCs based on block copolymers.
