A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The su...A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray （EDAX） show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.展开更多
A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through ...A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine （UTM） curves and alternating current （AC） impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope （FE-SEM） and atomic force microscope （AFM）. Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity （RH）. In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.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
A series of diblock copolymers composed of methyl methacrylate and 2-perfluorooctylethyl methacry-late(PMMA144-b-PFMAn) with various PFMA block lengths were prepared by atom transfer radical po-lymerization(ATRP).The ...A series of diblock copolymers composed of methyl methacrylate and 2-perfluorooctylethyl methacry-late(PMMA144-b-PFMAn) with various PFMA block lengths were prepared by atom transfer radical po-lymerization(ATRP).The surface structures and properties of these polymers in the solid state and in solution were investigated using contact angle measurement,X-ray photoelectron spectroscopy(XPS),sum frequency generation(SFG) vibrational spectroscopy,surface tension and dynamic laser light scattering(DLS).It was found that with increasing PFMA block length,water and oil repellency de-creased,the ratio of F/C increased with increasing film depth,and the degree of ordered packing of the perfluoroalkyl side chains at the surface decreased.When the number of PFMA block units reached 10,PMMA segments were detected at the copolymer surface,which was attributed to the PFMA block length affecting molecular aggregation structure of the copolymer in the solution and the interfacial structure at the air/liquid interface,which in turn affects surface structure formation during solution solidification.The results suggest that copolymer solution properties play an important role in struc-ture formation on the solid surface.展开更多
A novel fluorinated triblock copolymer incorporating 2-ethylhexyl methacrylate （EHMA）, tert-butyl methacrylate （tBMA） and 1H,1H,2H,2H-perfluorodecyl acrylate （FA） （PEHMA-b-PtBMA-b-PFA） was first synthesized us...A novel fluorinated triblock copolymer incorporating 2-ethylhexyl methacrylate （EHMA）, tert-butyl methacrylate （tBMA） and 1H,1H,2H,2H-perfluorodecyl acrylate （FA） （PEHMA-b-PtBMA-b-PFA） was first synthesized using three successive reversible addition fragmentation chain transfer （RAFT） polymerization and the subsequent hydrolyzing at acidic condition. The as-fabricated triblock copolymer exhibited an interesting morphology evolution from the multi-compartment rod-like structure to spherical structure along with the addition of a selective solution. At the same time, a visible phase separation domain could be seen in the core area due to the existence of fluorocarbon segments. Furthermore, the self- assembly behavior of the triphilic copolymer at different pH was also verified by transmission electron microscopy, as well as the dynamic light scattering. These stimuli-responsive multi-compartment nanostructures may have potential applications in drug delivery.展开更多
Fluorinated block copolymers composed of a polystyrene(Sx) first block and a polyacrylate second block carrying hydrophobic/lipophobic perfluorohexyl side chains(AF) were prepared by atom transfer radical polymerizati...Fluorinated block copolymers composed of a polystyrene(Sx) first block and a polyacrylate second block carrying hydrophobic/lipophobic perfluorohexyl side chains(AF) were prepared by atom transfer radical polymerization(ATRP). Fluorescence emission properties were imparted to the copolymers by incorporation in the second block of a julolidine-based fluorescent molecular rotor(JCBF). The synthesized block copolymers were used as the fluorescent low-surface energy thin top-layer onto a polystyrene bottom-layer to produce novel two-layer film vapochromic sensors. Contact angle and X-ray photoelectron spectroscopy(XPS) measurements revealed that the two-layer film surfaces were hydrophobic and lipophobic at the same time and highly enriched in fluorine content as a result of the effective segregation of the perfluorinated tails to the polymer-air interface.The fluorescence intensity of the two-layer films decreased significantly when they were exposed to vapours of organic solvents,including tetrahydrofurane, chloroform, and trifluorotoluene. However, an AF content-dependent sensing behaviour was also observed, with the two-layer films containing the copolymer with the shorter fluorinated block giving a more rapid and almost quantitative decrease in fluorescence variation. Fluorescence emission of the films was also proved to vary with temperature.Both the vapochromic and thermochromic responses were reversible after successive solicitation cycles. The fluorescence variation of the two-layer films was much more marked than that of the corresponding PS/JCBF blend, thus providing a system potentially applicable as highly sensitive volatile organic compound(VOC) sensor, thanks to the active role of the fluorinated block in promoting the migration of the fluorophore to the outermost surface layers.展开更多
The diblock copolymers of methyl acrylate and perfluoroalkyl ethyl acrylate(FAEA) were synthesized by atom transfer radical polymerization (ATRP).GPC, 1H-NMR and fluorine-elementary analysis (F-EA) were used to study ...The diblock copolymers of methyl acrylate and perfluoroalkyl ethyl acrylate(FAEA) were synthesized by atom transfer radical polymerization (ATRP).GPC, 1H-NMR and fluorine-elementary analysis (F-EA) were used to study the structure of the block copolymers.To combine GPC with NMR and to combine GPC with F-EA were used to calculate the block length.It was found interestingly that the results of 1H-NMR showed a “temperature-dependent" feature.It means the relative ratios of MA block to FAEA block calculated from NMR were changed with measuring temperature.It might be caused by the formation of molecular association.Temperature and solvents can affect the degree of association.Therefore, 1H-NMR and GPC can’t be used in quantitative analysis of the fluorinated diblock copolymer.To combine GPC with F-EA is suitable for the characterization of fluorinated diblock copolymers.展开更多
基金This work was partly supported by the National Natural Science Foundation of China (No. 50273008)Qingdao Municipal Science and Technology Commission.
文摘A series of copolymers comprising butylmethacrylate, styrene, butylacrylate, hydroxypropyl acrylate and perfluoroalkyl methacrylate were synthesized by the free radical polymerization using BPO as an initiator. The surface property of the copolymer films was subsequently characterized. The contact angle measurements and energy dispersive analysis of X-ray （EDAX） show that the length and content of perfluoroalkyl side chains in the copolymers are crucial for the preparation of the film with low surface energy. At a given content of fluorinated monomers in the copolymers, the longer the perfluoroalkyl side chain, the larger the water contact angle of the copolymer films will be. On the other hand, the higher the content of fluorinated monomers, the lower the surface energy is. The water contact angle increases with the increase of the fluorinated monomer content and reaches a plateau at 3 wt% of fluorinated monomer content.
基金supported by the Korea Institute of Energy Technology Evaluation and Planning(KETEP)the Ministry of Trade,Industry&Energy(MOTIE)of the Republic of Korea(No.20164030201070)supported by Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT and future Planning(NRF-2017R1A2B4005230)
文摘A ternary hybrid membrane architecture consisting of sulfonated fluorinated multi-block copolymer （SFMC）, sulfonated （poly ether ether ketone） （SPEEK） and I or 5 wt% graphene oxide （GO） was fabricated through a facile solution casting approach. The simple, but effective monomer sulfonation was performed for SFMC to create compact and rigid hydrophobic backbone structures, while conventional random sulfonation was carried-out for SPEEK. Hydrophilic-hydrophobic-hydrophilic structure of SFMC enhances the compatibility with SPEEK and GO and allows for an unprecedented approach to alter me- chanical strength and proton conductivity of ternary hybrid membrane, as verified from universal test machine （UTM） curves and alternating current （AC） impedance plots. The impact of GO integration on the morphology and roughness of hybrid membrane was scrutinized using field emission scanning electron microscope （FE-SEM） and atomic force microscope （AFM）. Ternary hybrid showed uniform intercalation of GO nanosheets throughout the entire surface of membrane with an increased surface roughness of 8.91 nm. The constructed ternary hybrid membrane revealed excellent water absorption, ion exchange capacity and gas barrier properties, while retaining reasonable dimensional stability. The well-optimized ternary hybrid membrane containing 5 wt% GO revealed a maximum proton conductivity of 111.9 mS/cm, which is higher by a factor of two-fold with respect to that of bare SFMC membrane. The maximum PEMFC power density of 528.07mW/cm2 was yielded by ternary hybrid membrane at a load current density of 1321.1 mA/cm2 when operating the cell at 70 ℃ under 100% relative humidity （RH）. In comparison, a maximum power density of only 182.06 mW/cm2 was exhibited by the bare SFMC membrane at a load current density of 455.56 mA/cm2 under same operating conditions.
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.
基金Supported by the National Natural Science Foundation of China(Grant Nos. 50573069 and 20704038)Program for Changjiang Scholars and Innovative Research Team in University (Grant No.IRT 0654)
文摘A series of diblock copolymers composed of methyl methacrylate and 2-perfluorooctylethyl methacry-late(PMMA144-b-PFMAn) with various PFMA block lengths were prepared by atom transfer radical po-lymerization(ATRP).The surface structures and properties of these polymers in the solid state and in solution were investigated using contact angle measurement,X-ray photoelectron spectroscopy(XPS),sum frequency generation(SFG) vibrational spectroscopy,surface tension and dynamic laser light scattering(DLS).It was found that with increasing PFMA block length,water and oil repellency de-creased,the ratio of F/C increased with increasing film depth,and the degree of ordered packing of the perfluoroalkyl side chains at the surface decreased.When the number of PFMA block units reached 10,PMMA segments were detected at the copolymer surface,which was attributed to the PFMA block length affecting molecular aggregation structure of the copolymer in the solution and the interfacial structure at the air/liquid interface,which in turn affects surface structure formation during solution solidification.The results suggest that copolymer solution properties play an important role in struc-ture formation on the solid surface.
基金financially supported by the National Natural Science Foundation of China(Nos.51622301 and 51573046)Fundamental Research Funds for the Central Universities(Nos.B14018,WD1616010 and 222201717001)
文摘A novel fluorinated triblock copolymer incorporating 2-ethylhexyl methacrylate （EHMA）, tert-butyl methacrylate （tBMA） and 1H,1H,2H,2H-perfluorodecyl acrylate （FA） （PEHMA-b-PtBMA-b-PFA） was first synthesized using three successive reversible addition fragmentation chain transfer （RAFT） polymerization and the subsequent hydrolyzing at acidic condition. The as-fabricated triblock copolymer exhibited an interesting morphology evolution from the multi-compartment rod-like structure to spherical structure along with the addition of a selective solution. At the same time, a visible phase separation domain could be seen in the core area due to the existence of fluorocarbon segments. Furthermore, the self- assembly behavior of the triphilic copolymer at different pH was also verified by transmission electron microscopy, as well as the dynamic light scattering. These stimuli-responsive multi-compartment nanostructures may have potential applications in drug delivery.
基金supported by the University of Pisa (fondi Progetti di Ricerca di Ateneo, PRA_2017_28)
文摘Fluorinated block copolymers composed of a polystyrene(Sx) first block and a polyacrylate second block carrying hydrophobic/lipophobic perfluorohexyl side chains(AF) were prepared by atom transfer radical polymerization(ATRP). Fluorescence emission properties were imparted to the copolymers by incorporation in the second block of a julolidine-based fluorescent molecular rotor(JCBF). The synthesized block copolymers were used as the fluorescent low-surface energy thin top-layer onto a polystyrene bottom-layer to produce novel two-layer film vapochromic sensors. Contact angle and X-ray photoelectron spectroscopy(XPS) measurements revealed that the two-layer film surfaces were hydrophobic and lipophobic at the same time and highly enriched in fluorine content as a result of the effective segregation of the perfluorinated tails to the polymer-air interface.The fluorescence intensity of the two-layer films decreased significantly when they were exposed to vapours of organic solvents,including tetrahydrofurane, chloroform, and trifluorotoluene. However, an AF content-dependent sensing behaviour was also observed, with the two-layer films containing the copolymer with the shorter fluorinated block giving a more rapid and almost quantitative decrease in fluorescence variation. Fluorescence emission of the films was also proved to vary with temperature.Both the vapochromic and thermochromic responses were reversible after successive solicitation cycles. The fluorescence variation of the two-layer films was much more marked than that of the corresponding PS/JCBF blend, thus providing a system potentially applicable as highly sensitive volatile organic compound(VOC) sensor, thanks to the active role of the fluorinated block in promoting the migration of the fluorophore to the outermost surface layers.
文摘The diblock copolymers of methyl acrylate and perfluoroalkyl ethyl acrylate(FAEA) were synthesized by atom transfer radical polymerization (ATRP).GPC, 1H-NMR and fluorine-elementary analysis (F-EA) were used to study the structure of the block copolymers.To combine GPC with NMR and to combine GPC with F-EA were used to calculate the block length.It was found interestingly that the results of 1H-NMR showed a “temperature-dependent" feature.It means the relative ratios of MA block to FAEA block calculated from NMR were changed with measuring temperature.It might be caused by the formation of molecular association.Temperature and solvents can affect the degree of association.Therefore, 1H-NMR and GPC can’t be used in quantitative analysis of the fluorinated diblock copolymer.To combine GPC with F-EA is suitable for the characterization of fluorinated diblock copolymers.
