Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bendi...Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.展开更多
Two-dimensional(2D)hybrid perovskites with the Ruddlesden-Popper lattice(A')_(2)(A)_(n-1)M_(n)X_(3n+1)are emerging as the promising optoelectronic candidates,both the inorganic and organic ingredients of which can...Two-dimensional(2D)hybrid perovskites with the Ruddlesden-Popper lattice(A')_(2)(A)_(n-1)M_(n)X_(3n+1)are emerging as the promising optoelectronic candidates,both the inorganic and organic ingredients of which can be tailored to modulate the physical properties.Nevertheless,there is a scarcity of 2D multilayered motifs with the A-site large-size cations occupying perovskite cavities.Here,by rational mixedcation alloying,we present a new 2D hybrid perovskite,(4-TFBMA)_(2)(DMA)Pb_(2)I_(7)(1),in which the secondary cation of CH_(3)NH_(2)CH_(3)^(+)(DMA)is located inside the perovskite cage while the aromatic 4-(trifluoromethyl)benzylammonium(4-TFBMA)cation acts as a spacer moiety.Benefiting from the quantum structure of alternating organic spacers and inorganic networks,crystal-array detectors of 1 show fascinating in-plane photodetection responses of large detectivity(~2.95×10^(12)Jones)and responsivity(~1.97AW^(-1)),comparable to those of some inorganic 2D counterparts.In addition,a fast response rate(~264μs)and a low dark current are also realized,related to the high crystalline quality and suppression of the hopping barrier due to the insulating organic spacing layers.This result sheds light on the further exploration of new 2D hybrid perovskites toward high-performance photodetector applications.展开更多
基金supported by the National Natural Science Foundation of China (50333020 & 50773070)National Basic Research Program of China ((973 Program,2009CB930104)+1 种基金China Postdoctoral Science Foundation (20100480085)Grand Science and Technology Special Project of Zhejiang Province (2008C11087)
文摘Chitosan (CS) is one promising material as a temporary mechanical supporter for bone fracture internal fixation.In our previous work,we successfully fabricated CS rods through one in situ precipitation route.But bending strength and bending modulus of CS rods need to be improved to match the commercially available devices used for bone fracture internal fixation.In this research,CS rods were reinforced effectively through cross-linking reaction by using glutaraldehyde as the coupling reagent.Schiff’s base was detected by FTIR due to the chemical reaction between amino groups and aldehyde groups.Crystal plane space of CS rods became small during the formation of network structure.Microstructure was observed by SEM,indicating that layer-by-layer structure became much tighter after cross-linking reaction,and cracks in one layer turned around when they reached another layer to absorb energy.Bending strength and bending modulus of cross-linked CS rods could reach 186.3 MPa and 5.17 GPa,respectively.Compared with uncross-linked CS rods,they are increased by 101.6% and 26.1%,respectively.As a result,mechanical properties of CS rods are equivalent to the commercially available biodegradable devices.CS rods with excellent mechanical properties are a good candidate for bone fracture internal fixation.
基金supported by the National Natural Science Foundation of China(21875251,21833010,21525104,22075285 and 21921001)the Key Research Program of Frontier Sciences of the Chinese Academy of Sciences(ZDBS-LY-SLH024)+3 种基金Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(2021ZR126)the Natural Science Foundation of Fujian Province(2018H0047 and 2020J01112)the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB20010200)the Youth Innovation Promotion of the Chinese Academy of Sciences(2019301 and 2020307).
文摘Two-dimensional(2D)hybrid perovskites with the Ruddlesden-Popper lattice(A')_(2)(A)_(n-1)M_(n)X_(3n+1)are emerging as the promising optoelectronic candidates,both the inorganic and organic ingredients of which can be tailored to modulate the physical properties.Nevertheless,there is a scarcity of 2D multilayered motifs with the A-site large-size cations occupying perovskite cavities.Here,by rational mixedcation alloying,we present a new 2D hybrid perovskite,(4-TFBMA)_(2)(DMA)Pb_(2)I_(7)(1),in which the secondary cation of CH_(3)NH_(2)CH_(3)^(+)(DMA)is located inside the perovskite cage while the aromatic 4-(trifluoromethyl)benzylammonium(4-TFBMA)cation acts as a spacer moiety.Benefiting from the quantum structure of alternating organic spacers and inorganic networks,crystal-array detectors of 1 show fascinating in-plane photodetection responses of large detectivity(~2.95×10^(12)Jones)and responsivity(~1.97AW^(-1)),comparable to those of some inorganic 2D counterparts.In addition,a fast response rate(~264μs)and a low dark current are also realized,related to the high crystalline quality and suppression of the hopping barrier due to the insulating organic spacing layers.This result sheds light on the further exploration of new 2D hybrid perovskites toward high-performance photodetector applications.
