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2017 Volume 35 Issue 4
2017, 35(4): 455-479
doi: 10.1007/s10118-017-1907-8
Abstract:
Controlled synthesis of amphiphilic block copolymer nanoparticles in a convenient way is an important and interest topic in polymer science. In this review, three formulations of polymerization-induced self-assembly to in situ synthesize block copolymer nanoparticles are briefly introduced, which perform by reversible addition-fragmentation chain transfer (RAFT) polymerization under heterogeneous conditions, e.g., aqueous emulsion RAFT polymerization, dispersion RAFT polymerization and especially the recently proposed seeded RAFT polymerization. The latest developments in several selected areas on the synthesis of block copolymer nano-assemblies are highlighted.
Controlled synthesis of amphiphilic block copolymer nanoparticles in a convenient way is an important and interest topic in polymer science. In this review, three formulations of polymerization-induced self-assembly to in situ synthesize block copolymer nanoparticles are briefly introduced, which perform by reversible addition-fragmentation chain transfer (RAFT) polymerization under heterogeneous conditions, e.g., aqueous emulsion RAFT polymerization, dispersion RAFT polymerization and especially the recently proposed seeded RAFT polymerization. The latest developments in several selected areas on the synthesis of block copolymer nano-assemblies are highlighted.
2017, 35(4): 480-489
doi: 10.1007/s10118-017-1885-x
Abstract:
Three acceptor-donor-acceptor (A-D-A) conjugated oligomers, i.e., O1, O2 and O3, have been synthesized using diketopyrrolopyrrole (DPP) as an electron-acceptor unit, and naphtho[1, 2-b:5, 6-b']dithiophene (NDT), anthra[1, 2-b:5, 6-b']dithiophene (ADT) or dithieno[3, 2-b:3', 2'-b']naphtho[1, 2-b:5, 6-b']dithiophene (DTNDT) as electron-donor unit. These oligomers exhibit identical highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, which were ca.-5.1 and-3.3 eV, respectively. Upon thermal annealing, all three oligomers formed thin films with ordered microstructures, and their organic thin film transistors (OTFTs) exhibited p-type transport behavior. The mobility was increased with an extension of the size of D-units. O3 showed the best OTFT performance with the mobility of up to 0.20 cm2·V-1·s-1. The film quality of O3 was improved by adding 1 wt% poly (methylmethacrylate) (PMMA). In consequence, the mobility of the O3-based devices was further enhanced to 0.30 cm2·V-1·s-1.
Three acceptor-donor-acceptor (A-D-A) conjugated oligomers, i.e., O1, O2 and O3, have been synthesized using diketopyrrolopyrrole (DPP) as an electron-acceptor unit, and naphtho[1, 2-b:5, 6-b']dithiophene (NDT), anthra[1, 2-b:5, 6-b']dithiophene (ADT) or dithieno[3, 2-b:3', 2'-b']naphtho[1, 2-b:5, 6-b']dithiophene (DTNDT) as electron-donor unit. These oligomers exhibit identical highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels, which were ca.-5.1 and-3.3 eV, respectively. Upon thermal annealing, all three oligomers formed thin films with ordered microstructures, and their organic thin film transistors (OTFTs) exhibited p-type transport behavior. The mobility was increased with an extension of the size of D-units. O3 showed the best OTFT performance with the mobility of up to 0.20 cm2·V-1·s-1. The film quality of O3 was improved by adding 1 wt% poly (methylmethacrylate) (PMMA). In consequence, the mobility of the O3-based devices was further enhanced to 0.30 cm2·V-1·s-1.
2017, 35(4): 490-502
doi: 10.1007/s10118-017-1881-1
Abstract:
A series of novel hyperbranched polymers (HBPs) consisting of a 2, 7-subsituted 9-(heptadecan-9-yl)-9H-carbazole unit (A2+A2') and a tetra-substituted green thermally activated delayed fluorescence (TADF) dye of 2, 3, 5, 6-tetra (9H-carbazol-9-yl)-4-pyridinecarbonitrile (4CzCNPy, B4) have been synthesized via Suzuki cross-coupling reaction following an "A2+A2'+B4" method. The polymers are named according to the polymerization ratio of 4CzCNPy monomer (5 mol%, 10 mol% and 15 mol% for HBPs of P2-P4 respectively, and 0 mol% for the control linear polymer P1). Their thermal, optoelectronic and electrochemical properties have been characterized by a combination of techniques. All the polymers exhibit high thermal stability with the decomposition temperatures (Td) above 400℃ and glass transition temperatures (Tg) up to 98℃. Unfortunately, the incorporation of TADF moiety into these HBP materials induced non-TADF characteristics. However, when the HBPs functionalized as the host for our previously developed 4CzCNPy TADF dopant in solution processed devices, maximum external quantum efficiency of 5.7% and current efficiency of 17.9 cd/A have been achieved in P3-based device, which is significantly higher than those of 1.5% and 4.2 cd/A for the linear polymer P1.
A series of novel hyperbranched polymers (HBPs) consisting of a 2, 7-subsituted 9-(heptadecan-9-yl)-9H-carbazole unit (A2+A2') and a tetra-substituted green thermally activated delayed fluorescence (TADF) dye of 2, 3, 5, 6-tetra (9H-carbazol-9-yl)-4-pyridinecarbonitrile (4CzCNPy, B4) have been synthesized via Suzuki cross-coupling reaction following an "A2+A2'+B4" method. The polymers are named according to the polymerization ratio of 4CzCNPy monomer (5 mol%, 10 mol% and 15 mol% for HBPs of P2-P4 respectively, and 0 mol% for the control linear polymer P1). Their thermal, optoelectronic and electrochemical properties have been characterized by a combination of techniques. All the polymers exhibit high thermal stability with the decomposition temperatures (Td) above 400℃ and glass transition temperatures (Tg) up to 98℃. Unfortunately, the incorporation of TADF moiety into these HBP materials induced non-TADF characteristics. However, when the HBPs functionalized as the host for our previously developed 4CzCNPy TADF dopant in solution processed devices, maximum external quantum efficiency of 5.7% and current efficiency of 17.9 cd/A have been achieved in P3-based device, which is significantly higher than those of 1.5% and 4.2 cd/A for the linear polymer P1.
2017, 35(4): 503-514
doi: 10.1007/s10118-017-1899-4
Abstract:
A series of sphere-rod shape amphiphiles were designed and synthesized by connecting the rod-like oligofluorenes with different lengths (OFn) to the different positions of the spherical[60]fullerene (C60) through a rigid linkage. The conjugates were characterized by 1H-NMR, 13C-NMR, FTIR, EA and MALDI-TOF mass spectrometry. The optical and electronic properties of the conjugates were studied by UV-Vis absorption spectroscopy, fluorescence spectrometry, and cyclic voltammetry. The results from UV-Vis absorption spectroscopy and cyclic voltammetry indicated that the energy profiles of C60 and OFn remained unchanged when different lengths of OFn were attached to C60. The electron affinities of the OFn-C60 conjugates were close to that of C60, while slight electronic interaction was found between the two individual chromophores (C60 and OFn) in their ground states. The fluorescence spectra exhibited a complete fluorescence quenching in the toluene solution, suggesting an effective energy transfer from OFn to C60. It presents a systematic study on the self-assembly, structure-property relationship, and potential technical applications of the conjugates.
A series of sphere-rod shape amphiphiles were designed and synthesized by connecting the rod-like oligofluorenes with different lengths (OFn) to the different positions of the spherical[60]fullerene (C60) through a rigid linkage. The conjugates were characterized by 1H-NMR, 13C-NMR, FTIR, EA and MALDI-TOF mass spectrometry. The optical and electronic properties of the conjugates were studied by UV-Vis absorption spectroscopy, fluorescence spectrometry, and cyclic voltammetry. The results from UV-Vis absorption spectroscopy and cyclic voltammetry indicated that the energy profiles of C60 and OFn remained unchanged when different lengths of OFn were attached to C60. The electron affinities of the OFn-C60 conjugates were close to that of C60, while slight electronic interaction was found between the two individual chromophores (C60 and OFn) in their ground states. The fluorescence spectra exhibited a complete fluorescence quenching in the toluene solution, suggesting an effective energy transfer from OFn to C60. It presents a systematic study on the self-assembly, structure-property relationship, and potential technical applications of the conjugates.
2017, 35(4): 515-523
doi: 10.1007/s10118-017-1910-0
Abstract:
A simple and facile synthetic methodology for fabricating the regenerated silk fibroin (RSF)-based hydrogel which consisted of the in situ generated magnetic ferriferous oxide (Fe3O4) was developed. Using the co-precipitation of Fe2+ and Fe3+ within the RSF-based hydrogel with 90% RSF and 10% HPMC (hydroxypropyl methyl cellulose), the as-prepared RSF/Fe3O4 hydrogel not only showed high strength of saturation magnetization, but also exhibited excellent catalytic activities. For example, with the assistant of 3, 3', 5, 5'-tetramethylbenzidine (TMB), the RSF/Fe3O4 hydrogel could detect H2O2 at a concentration as low as 1×10-6 mol·L-1. In addition, the catalytic activities were able to be maintained for a long term under various conditions. These findings suggest that the RSF-based materials can be endowed with interesting properties, and have great potential for the applications in the fields of biotechnology and environmental chemistry.
A simple and facile synthetic methodology for fabricating the regenerated silk fibroin (RSF)-based hydrogel which consisted of the in situ generated magnetic ferriferous oxide (Fe3O4) was developed. Using the co-precipitation of Fe2+ and Fe3+ within the RSF-based hydrogel with 90% RSF and 10% HPMC (hydroxypropyl methyl cellulose), the as-prepared RSF/Fe3O4 hydrogel not only showed high strength of saturation magnetization, but also exhibited excellent catalytic activities. For example, with the assistant of 3, 3', 5, 5'-tetramethylbenzidine (TMB), the RSF/Fe3O4 hydrogel could detect H2O2 at a concentration as low as 1×10-6 mol·L-1. In addition, the catalytic activities were able to be maintained for a long term under various conditions. These findings suggest that the RSF-based materials can be endowed with interesting properties, and have great potential for the applications in the fields of biotechnology and environmental chemistry.
2017, 35(4): 524-533
doi: 10.1007/s10118-017-1883-z
Abstract:
The gel-spun ultra-high molecular weight polyethylene (UHMWPE) fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length ( < Lshish >) and shish misorientation (Bϕ) of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.
The gel-spun ultra-high molecular weight polyethylene (UHMWPE) fibers were prepared at the industrial production line with different gel solution concentrations of 15 wt%, 18 wt% and 24 wt%. The difference in ultimate structure and mechanical properties of UHMWPE fibers for different gel solution concentrations were analyzed by tensile testing, differential scanning calorimetry (DSC), wide angle X-ray diffraction (WAXD) and small angle X-ray scattering (SAXS). With the increase of gel solution concentration, the ultimate mechanical properties of UHMWPE fibers were decreased and the crystallization and orientation of UHMWPE fibers became inferior. Besides, both the average shish length ( < Lshish >) and shish misorientation (Bϕ) of UHMWPE fibers were decreased with the increase of gel solution concentration. In addition, the appropriate increase of spinning temperature led to the further optimization of the ultimate structure and mechanical properties of UHMWPE fibers.
2017, 35(4): 534-546
doi: 10.1007/s10118-017-1916-7
Abstract:
Stimuli-responsive polymers have undoubtedly been of great interest in the past decades due to a variety of their potential applications in biomedical territory. However, their non-degradability limits their in vivo applications. Herein, we report a novel pH and temperature dual-stimuli responsive-poly (β-amino ester). The pH/temperature sensitivities are interrelated and can be easily tuned by changing PEG-diacrylate chain length and the percentage of biamines in the feed ratio. These dual-responsive polymers are very useful in drug delivery. Reaction of methyl ether poly (ethylene glycol) (MPEG) and poly (β-amino ester) resulted in an amphiphilic MPEG-PBAE block copolymer which could form nanoparticles by self-assembly. A hydrophobic drug (DOX) was loaded in the self-assembled nanoparticles at low temperature without using organic solvents. The loaded drug was released very slowly and steadily at 37℃ under physiological conditions (pH 7.4), but rapidly released from the micelles in weakly acidic environments (pH 6.4 and 5.0) for intracellular drug release. Thus, these poly (β-amino ester) polymers constitute ideal drug carriers since their thermal sensitivity allows the drug loadings without using organic solvent and their pH sensitivity permits fast intracellular drug release.
Stimuli-responsive polymers have undoubtedly been of great interest in the past decades due to a variety of their potential applications in biomedical territory. However, their non-degradability limits their in vivo applications. Herein, we report a novel pH and temperature dual-stimuli responsive-poly (β-amino ester). The pH/temperature sensitivities are interrelated and can be easily tuned by changing PEG-diacrylate chain length and the percentage of biamines in the feed ratio. These dual-responsive polymers are very useful in drug delivery. Reaction of methyl ether poly (ethylene glycol) (MPEG) and poly (β-amino ester) resulted in an amphiphilic MPEG-PBAE block copolymer which could form nanoparticles by self-assembly. A hydrophobic drug (DOX) was loaded in the self-assembled nanoparticles at low temperature without using organic solvents. The loaded drug was released very slowly and steadily at 37℃ under physiological conditions (pH 7.4), but rapidly released from the micelles in weakly acidic environments (pH 6.4 and 5.0) for intracellular drug release. Thus, these poly (β-amino ester) polymers constitute ideal drug carriers since their thermal sensitivity allows the drug loadings without using organic solvent and their pH sensitivity permits fast intracellular drug release.
2017, 35(4): 547-557
doi: 10.1007/s10118-017-1901-1
Abstract:
Three types of organic compounds-two carboxylic acids and an anhydride, were used as additives for polyketone (PK). The effect of the additive structure and their feed ratios on the melting temperature, crystallization temperature, and crystallization rate of PK were studied. We found that the crystallization temperature could be reduced significantly by introducing a small quantity of organic additive, in particular, an anhydride. On addition of 1 phr of anhydride, the crystallization temperature was reduced by 10.7¦. Therefore, the non-isothermal crystallization kinetics of aliphatic PK/anhydride blends with various feed ratios was investigated using DSC. The results were analyzed by various theoretical models, such as Avrami, Ozawa and combined Avrami-Ozawa models.
Three types of organic compounds-two carboxylic acids and an anhydride, were used as additives for polyketone (PK). The effect of the additive structure and their feed ratios on the melting temperature, crystallization temperature, and crystallization rate of PK were studied. We found that the crystallization temperature could be reduced significantly by introducing a small quantity of organic additive, in particular, an anhydride. On addition of 1 phr of anhydride, the crystallization temperature was reduced by 10.7¦. Therefore, the non-isothermal crystallization kinetics of aliphatic PK/anhydride blends with various feed ratios was investigated using DSC. The results were analyzed by various theoretical models, such as Avrami, Ozawa and combined Avrami-Ozawa models.
2017, 35(4): 558-568
doi: 10.1007/s10118-017-1917-6
Abstract:
Zinc phenylphosphonate (PPZn), a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly (ethylene adipate) (PEA) to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.
Zinc phenylphosphonate (PPZn), a benign and biocompatible nucleating agent, was prepared and incorporated into the biodegradable poly (ethylene adipate) (PEA) to investigate its effect on the crystallization behavior, crystallization kinetics and spherulite morphology of PEA. Upon addition of PPZn, the crystallization temperature and crystallinity of PEA in the non-isothermal crystallization process increased significantly. Analysis of crystallization kinetics by Avrami equation suggests that the crystallization time shortened greatly and crystallization rate increased markedly after addition of PPZn. In the presence of PPZn, the spherulite size decreased and spherulite density increased significantly. It suggests that PPZn is an efficient nucleating agent for the crystallization of PEA. The accelerated crystallization in the presence of PPZn is mainly attributed to the epitaxial nucleation of PEA crystals on the surface of PPZn crystals, that is, a perfect lattice matching between PEA crystal and PPZn crystal occurs.
2017, 35(4): 569-580
doi: 10.1007/s10118-017-1900-2
Abstract:
The polypropylene-graft-polyisoprene (PP-g-PIP) copolymers with different side chain length were synthesized by the combination of solid phase graft and anionic polymerization. The copolymers were characterized by nuclear magnetic resonance spectrum (1H-NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Five PP/PP-g-PIP blends with PP-g-PIP as a flexibilizer to toughen PP were prepared and characterized by scanning electron microscope (SEM), dynamic mechanical analysis (DMA), DSC, wide-angle X-ray diffraction (WAXD). Their morphologies, glass transition temperatures, crystallinity and mechanical properties were investigated. All the results pointed out that the covalent bonding of PP and PIP increased the compatibility and interfacial adhesion, which led to PIP well dispersed in the system and small size PIP particles in the binary blends. In addition, the toughness of PP was improved while its tensile strength slightly decreased.
The polypropylene-graft-polyisoprene (PP-g-PIP) copolymers with different side chain length were synthesized by the combination of solid phase graft and anionic polymerization. The copolymers were characterized by nuclear magnetic resonance spectrum (1H-NMR), gel permeation chromatography (GPC) and differential scanning calorimetry (DSC). Five PP/PP-g-PIP blends with PP-g-PIP as a flexibilizer to toughen PP were prepared and characterized by scanning electron microscope (SEM), dynamic mechanical analysis (DMA), DSC, wide-angle X-ray diffraction (WAXD). Their morphologies, glass transition temperatures, crystallinity and mechanical properties were investigated. All the results pointed out that the covalent bonding of PP and PIP increased the compatibility and interfacial adhesion, which led to PIP well dispersed in the system and small size PIP particles in the binary blends. In addition, the toughness of PP was improved while its tensile strength slightly decreased.
