Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the ...Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ^(31)p NMR,~1H NMR,^(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated.The...展开更多
Polyphosphazene with phenoxy or 4-ester phenoxy as pendent groups are demonstrated as both ligands and host matrices for CsPbBr_(3) perovskite nanocrystals(NCs). These polymers produced fiexible nanocomposite films wi...Polyphosphazene with phenoxy or 4-ester phenoxy as pendent groups are demonstrated as both ligands and host matrices for CsPbBr_(3) perovskite nanocrystals(NCs). These polymers produced fiexible nanocomposite films with excellent NCs dispersion, optical transparency and stability in various extreme conditions. Both films remained stable even after 30 days of air storage. CsPbBr_(3) /poly[bis(phenoxy phosphazene)](PBPP) delivered better air and light stability, and CsPbBr_(3) /poly[bis(4-esterphenoxy)phosphazene](PBEPP) exhibited superior water and heat resistance. CsPbBr_(3) /PBEPP showed a greater increase in fiuorescence intensity under 365 nm UV light and demonstrated a 10% luminescence increase after 96 h of water immersion and even at high temperature(150℃). These findings thus provide new insight into fiexible luminescent CsPbBr_(3) films with high stability in optoelectronic applications.展开更多
A novel series of polyphosphazene-grafl-polystyrene （PP-g-PS） copolymers were successfully prepared by atom transfer radical polymerization （ATRP） of styrene monomers and brominated poly（bis（4-methylphenoxy）pho...A novel series of polyphosphazene-grafl-polystyrene （PP-g-PS） copolymers were successfully prepared by atom transfer radical polymerization （ATRP） of styrene monomers and brominated poly（bis（4-methylphenoxy）phosphazene） macroinitiator. The graft density and the graft length could be regulated by changing the bromination degree of the macroinitiator and the ATRP reaction time, respectively. The PP-g-PS copolymers readily underwent a regioselective sulfonation reaction, which occurred preferentially at the polystyrene sites, producing the sulfonated PP-g-PS copolymers with a range of ion exchange capacities. The resulting sulfonated PP-g-PS membranes prepared by solution casting showed high water uptake, low water swelling and considerable proton conductivity. They also exhibited good oxidative stability and high resistance to methanol crossover. Morphological studies of the membranes by transmission electron microscopy showed clear nanophase-separated structures resulted from hydrophobic polyphosphazene backbone and hydrophilic polystyrene sulfonic acid segments, indicating the formation of proton transferring tunnels. Therefore, these sulfonated copolymers may be candidate materials for proton exchange membranes in direct methanol fuel cell （DMFC） applications.展开更多
基金the National Natural Foundation of China(No. 20364002)the Natural Science Foundation of Yunnan Province(No.2005B0027 M),China
文摘Two novel biodegradable thermosensitive polyphosphazenes with lactic acid ester and methoxyethoxyethoxy side groups were synthesized via the macromolecular substitution reactions of poly(dichlorophosphazene) with the sodium salt of lactic acid ester and sodium methoxyethoxyethoxide.Their structures were confirmed by ^(31)p NMR,~1H NMR,^(13)C NMR,IR,DSC,and elemental analysis.The lower critical solution temperature(LCST) behavior in water and in vitro degradation property of the polymers was investigated.The...
基金supported by the National Science Foundation (NSF) of China (No. 51773010)the Weifang Science and Technology Development Plan Program (No. 2023GX005)。
文摘Polyphosphazene with phenoxy or 4-ester phenoxy as pendent groups are demonstrated as both ligands and host matrices for CsPbBr_(3) perovskite nanocrystals(NCs). These polymers produced fiexible nanocomposite films with excellent NCs dispersion, optical transparency and stability in various extreme conditions. Both films remained stable even after 30 days of air storage. CsPbBr_(3) /poly[bis(phenoxy phosphazene)](PBPP) delivered better air and light stability, and CsPbBr_(3) /poly[bis(4-esterphenoxy)phosphazene](PBEPP) exhibited superior water and heat resistance. CsPbBr_(3) /PBEPP showed a greater increase in fiuorescence intensity under 365 nm UV light and demonstrated a 10% luminescence increase after 96 h of water immersion and even at high temperature(150℃). These findings thus provide new insight into fiexible luminescent CsPbBr_(3) films with high stability in optoelectronic applications.
基金financially supported by the National Natural Science Foundation of China(No.51103012)
文摘A novel series of polyphosphazene-grafl-polystyrene （PP-g-PS） copolymers were successfully prepared by atom transfer radical polymerization （ATRP） of styrene monomers and brominated poly（bis（4-methylphenoxy）phosphazene） macroinitiator. The graft density and the graft length could be regulated by changing the bromination degree of the macroinitiator and the ATRP reaction time, respectively. The PP-g-PS copolymers readily underwent a regioselective sulfonation reaction, which occurred preferentially at the polystyrene sites, producing the sulfonated PP-g-PS copolymers with a range of ion exchange capacities. The resulting sulfonated PP-g-PS membranes prepared by solution casting showed high water uptake, low water swelling and considerable proton conductivity. They also exhibited good oxidative stability and high resistance to methanol crossover. Morphological studies of the membranes by transmission electron microscopy showed clear nanophase-separated structures resulted from hydrophobic polyphosphazene backbone and hydrophilic polystyrene sulfonic acid segments, indicating the formation of proton transferring tunnels. Therefore, these sulfonated copolymers may be candidate materials for proton exchange membranes in direct methanol fuel cell （DMFC） applications.
