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
Most research on copolymers with fluorinated monomers has focused on the relationship between fluorinated monomer content and the corresponding surface structure. However,the influence of the non-fluorinated block on ...Most research on copolymers with fluorinated monomers has focused on the relationship between fluorinated monomer content and the corresponding surface structure. However,the influence of the non-fluorinated block on the surface structure of the copolymer film is unknown. Various molecular weight poly(butyl methacrylates) (PBMA) end-capped with 2-perfluorooctylethyl methacrylate (FMA) units (PBMA-ec-FMA) have been synthesized by atom transfer radical polymerization (ATRP). The effect of the PBMA block length on the surface structure and properties of the polymers both in the solid state and in solution was investigated using various techniques. X-ray photoelectron spectroscopy (XPS),sum frequency generation (SFG) vibrational spectroscopy and X-ray diffraction (XRD) analyses indicated that longer PBMA blocks enhanced both the enrichment of the fluorinated moieties and the order of the packing orientation of the perfluoroalkyl side chains on the surface. This enhancement was attributed mainly to the molecular aggregate structure of the end-capped polymers with long PBMA blocks in the solution and to the interfacial structure at the air/liquid interface,which favors the -(CF2)7CF3 moieties self-assembling on the polymer surface during film formation. This observation suggests that the polyacrylate block structure in fluorinated diblock copolymers,in addition to the fluorinated monomer content,plays an important role in structure formation on the solid surface.展开更多
Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excelle...Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excellent solubility and good thermal stability.The structure of the polymer was confirmed by FT-IR and 1H NMR spectrum.The calculated degree of branching of our product was 52%.By exploring the influence of several different solvent systems,the yield of the polymer increased in the solvent system of DMAc/LiCl.Two kinds of metal complexes were obtained by chelation of the polyamide with Cu2+ and Ni2+,and the metal contents of the complexes were determined by complexometric titration.The magnetic behaviors of the complexes were examined as a function of magnetic field strength at 5 K,and as a function of temperature (5–300 K) at a magnetic field strength of 2.4 × 106 A/m.The results indicated that the complexes were soft ferromagnetic materials with Curie-Weiss temperature at 102 K and 53 K,respectively.展开更多
The surface chemical structure development in solution-cast styrene(S)/butadiene(B) block copolymer films as a function of solvent evaporation time was investigated using sum frequency generation vibrational spectrosc...The surface chemical structure development in solution-cast styrene(S)/butadiene(B) block copolymer films as a function of solvent evaporation time was investigated using sum frequency generation vibrational spectroscopy(SFG).The surface structure formation of the styrene(S)/butadien(B) block copolymer(30 wt% PS) films during the solution-to-film process was found to be controlled mainly by dynamic factors,such as the mobility of the PB block in solution.For SB diblock copolymers,a pure PB surface layer was formed only when the film was cast by dilute toluene solution.With increasing concentration of casting solution,PB and PS components were found to coexist on the film surface,and the morphology of the PB component on the film surface changed from cylindrical rods to spheres.For SBS triblock copolymers,a small amount of PS component existed on the surface even if the film was cast by 1.0 wt% toluene solution.In addition,PS components at the outermost layer of the film increased and the length of PB cylindrical rods on the surface decreased with increasing concentration of casting solution.展开更多
Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic ...Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic poly（ethylene glycol）（PEG） blocks were precisely synthesized by a combination of ring-opening polymerization（ROP）, atom transfer radical polymerization（ATRP） and ＂click＂ reaction. Such star copolymers could self-assemble into ＂core-shell-corona＂ micelles and ＂multi-layer＂ vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly（acrylic acidXPAA） blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates m response to pH values.展开更多
The catalyst system composed of lanthanide Schiff-base complexes with [3,5-tBu2-2-（O）C6H2CH=NC6Hs]3Ln（THF）（Ln（Salen）3, Ln = Sc, Y, La, Nd, Sm, Gd, Yb） and triisobutyl aluminum shows high activity for n-octylox...The catalyst system composed of lanthanide Schiff-base complexes with [3,5-tBu2-2-（O）C6H2CH=NC6Hs]3Ln（THF）（Ln（Salen）3, Ln = Sc, Y, La, Nd, Sm, Gd, Yb） and triisobutyl aluminum shows high activity for n-octyloxyallene （A） homopolymerization with narrow molecular weight distribution （MWD）. The influences of reaction conditions on polymerization behavior are in- vestigated, and poly（n-octyloxyallene） has a weight average molecular weight （Mw） of 20.6 ~ 103 with MWD of 1.39 and 100% yield is obtained under the optimum conditions： [A1]/[Y] = 50 mol/mol, [A]/[Y] = 100 mol/mol, with polymerization at 80 ~C for 16 h in bulk. The kinetic studies of n-octyloxyallene homopolymerization indicate that the polymerization rate is first-order with respect to the monomer concentration and shows some controlled polymerization characteristics. Random co- polymer of n-octyloxyallene with styrene is obtained by using the same binary catalyst system; the reactivity ratios of the comonomer determined by Kelen-Ttld/Ss method are rA = 1.20 and rst = 0.35, respectively, the ratio of each segment and Mw of the resulting copolymer could be controlled by varying the feed ratio of each monomer. Determined by differential scanning calorimetry, the copolymers obtained show only one glass transition temperature, which increases gradually with the increase of styrene content in the copolymer.展开更多
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Supported by the National Natural Science Foundation of China (Grant Nos. 50573069 & 20704038) Program for Changjiang Scholars and Innovative Re-search Team in University (Grant No. IRT 0654)
文摘Most research on copolymers with fluorinated monomers has focused on the relationship between fluorinated monomer content and the corresponding surface structure. However,the influence of the non-fluorinated block on the surface structure of the copolymer film is unknown. Various molecular weight poly(butyl methacrylates) (PBMA) end-capped with 2-perfluorooctylethyl methacrylate (FMA) units (PBMA-ec-FMA) have been synthesized by atom transfer radical polymerization (ATRP). The effect of the PBMA block length on the surface structure and properties of the polymers both in the solid state and in solution was investigated using various techniques. X-ray photoelectron spectroscopy (XPS),sum frequency generation (SFG) vibrational spectroscopy and X-ray diffraction (XRD) analyses indicated that longer PBMA blocks enhanced both the enrichment of the fluorinated moieties and the order of the packing orientation of the perfluoroalkyl side chains on the surface. This enhancement was attributed mainly to the molecular aggregate structure of the end-capped polymers with long PBMA blocks in the solution and to the interfacial structure at the air/liquid interface,which favors the -(CF2)7CF3 moieties self-assembling on the polymer surface during film formation. This observation suggests that the polyacrylate block structure in fluorinated diblock copolymers,in addition to the fluorinated monomer content,plays an important role in structure formation on the solid surface.
基金supported by the National Natural Science Foundation of China (20674071)the National Basic Research Program of China (973 Program,2005CB623800)
文摘Based on the polycondensation of bifunctional 2,2′-diamino-4,4′-bithiazole(DABT) and trifunctional 1,3,5-benzenetricarbonyl trichloride (BTC),a novel hyperbranched aromatic polyamide PBD was synthesized with excellent solubility and good thermal stability.The structure of the polymer was confirmed by FT-IR and 1H NMR spectrum.The calculated degree of branching of our product was 52%.By exploring the influence of several different solvent systems,the yield of the polymer increased in the solvent system of DMAc/LiCl.Two kinds of metal complexes were obtained by chelation of the polyamide with Cu2+ and Ni2+,and the metal contents of the complexes were determined by complexometric titration.The magnetic behaviors of the complexes were examined as a function of magnetic field strength at 5 K,and as a function of temperature (5–300 K) at a magnetic field strength of 2.4 × 106 A/m.The results indicated that the complexes were soft ferromagnetic materials with Curie-Weiss temperature at 102 K and 53 K,respectively.
基金support from the National Natural Science Foundation of China (20874089)the Graduate Research Foundation of Zhejiang Province (YK2010056)
文摘The surface chemical structure development in solution-cast styrene(S)/butadiene(B) block copolymer films as a function of solvent evaporation time was investigated using sum frequency generation vibrational spectroscopy(SFG).The surface structure formation of the styrene(S)/butadien(B) block copolymer(30 wt% PS) films during the solution-to-film process was found to be controlled mainly by dynamic factors,such as the mobility of the PB block in solution.For SB diblock copolymers,a pure PB surface layer was formed only when the film was cast by dilute toluene solution.With increasing concentration of casting solution,PB and PS components were found to coexist on the film surface,and the morphology of the PB component on the film surface changed from cylindrical rods to spheres.For SBS triblock copolymers,a small amount of PS component existed on the surface even if the film was cast by 1.0 wt% toluene solution.In addition,PS components at the outermost layer of the film increased and the length of PB cylindrical rods on the surface decreased with increasing concentration of casting solution.
基金Supported by the Distinguished Young Investigator Fund of Zhejiang Province, China（No.LR18B040001）, the National Natural Science Foundation of China（No.51603180）, the Fundamental Research Funds for the Central Universities, China （No.2017QNA4038） and the China Postdoctoral Science Foundation（No.2015M580517）.
文摘Well-defined amphiphilic seven-arm star triblock copolymers containing hydrophobic crystalline poly（e-caprolactoneXPCL） blocks, hydrophobic non-crystalline poly（tert-butyl acrylate）（PtBA） blocks and hydrophilic poly（ethylene glycol）（PEG） blocks were precisely synthesized by a combination of ring-opening polymerization（ROP）, atom transfer radical polymerization（ATRP） and ＂click＂ reaction. Such star copolymers could self-assemble into ＂core-shell-corona＂ micelles and ＂multi-layer＂ vesicles depending on the fraction of each block. Meanwhile, the selective hydrolysis of middle PtBA blocks into the poly（acrylic acidXPAA） blocks allowed the star block copolymers to further change their morphologies of aqueous aggregates m response to pH values.
基金the financial support of the National Natural Science Foundation of China (21174121)the Special Funds for Major Basic Research Projects (G2011CB606001)Zhejiang Provincial Top Key Discipline of New Materials and Process Engineering(20110926)
文摘The catalyst system composed of lanthanide Schiff-base complexes with [3,5-tBu2-2-（O）C6H2CH=NC6Hs]3Ln（THF）（Ln（Salen）3, Ln = Sc, Y, La, Nd, Sm, Gd, Yb） and triisobutyl aluminum shows high activity for n-octyloxyallene （A） homopolymerization with narrow molecular weight distribution （MWD）. The influences of reaction conditions on polymerization behavior are in- vestigated, and poly（n-octyloxyallene） has a weight average molecular weight （Mw） of 20.6 ~ 103 with MWD of 1.39 and 100% yield is obtained under the optimum conditions： [A1]/[Y] = 50 mol/mol, [A]/[Y] = 100 mol/mol, with polymerization at 80 ~C for 16 h in bulk. The kinetic studies of n-octyloxyallene homopolymerization indicate that the polymerization rate is first-order with respect to the monomer concentration and shows some controlled polymerization characteristics. Random co- polymer of n-octyloxyallene with styrene is obtained by using the same binary catalyst system; the reactivity ratios of the comonomer determined by Kelen-Ttld/Ss method are rA = 1.20 and rst = 0.35, respectively, the ratio of each segment and Mw of the resulting copolymer could be controlled by varying the feed ratio of each monomer. Determined by differential scanning calorimetry, the copolymers obtained show only one glass transition temperature, which increases gradually with the increase of styrene content in the copolymer.
