A new complex, [Ni2（L）4（H2O）8]（1, L1 = 4-（1H-imidazol-4-yl）benzoic acid）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. C...A new complex, [Ni2（L）4（H2O）8]（1, L1 = 4-（1H-imidazol-4-yl）benzoic acid）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in monoclinic, space group P21/c with α = 22.281（2）, b = 7.3959（7）, c = 24.978（3） ？, β = 90.876（10）, V = 4115.6（7） ？3, Z = 8, C20H22N4O8Ni, Mr = 505.13, Dc = 1.630 g/cm3, μ = 1.001 mm-1, S = 1.080, F（000） = 2096, the final R = 0.452 and wR = 0.1152 for 9380 observed reflections （I 〉 2σ（I））. The result of X-ray diffraction analysis revealed three different kinds of Ni（II） centre mononuclear molecules in the asymmetric unit. The independent mononuclear units are bridged to form a three-dimensional supramolecular polymer by extensive hydrogen bonds and C–H… non-covalent bonding interactions.展开更多
Thermal softening is an inevitable process in the physical network.Polyurethane(PU),a typical commercial material,is constructed by physical networks,which undergoes the serious thermal decay on mechanical properties ...Thermal softening is an inevitable process in the physical network.Polyurethane(PU),a typical commercial material,is constructed by physical networks,which undergoes the serious thermal decay on mechanical properties at high temperature.Herein,a physically cross-linked PU with a unique thermal stiffening behavior has been developed by incorporating B–N coordination with reversible B–O bonds.The B–N coordination can significantly improve the mechanical properties of the PU.The reversible B–O bonds(temperature dependent reversible transformation between B–OH and B–O–B)are conducive to constructing more multicoordination macromolecular crosslinking points and more stable B–N coordination bonds at high temperature,endowing the PU with the special thermal stiffening behavior for the first time.Such thermal stiffening behavior compensates for the bond breakage and the network destruction caused by heat,significantly expands the rubbery plateau and delays the entire chain motion of the thermoplastic PU.As a result,the terminal flow occurs at a higher temperature up to 200°C.The modulus retention ratio of the materials is up to 87%even at 145oC,which is much higher than that of the existing PU elastomer with the physical network and even some covalent cross-link PU.Simultaneously,the physical network ensures the recyclability of the PU,and the thermal stiffening behavior is still obtained in recycled PU.This work provides a simple strategy to impart thermal stiffening behavior to the physically crosslinked PU,thereby significantly extending the operating temperature range of thermoplastic PU,which can potentially expand the scopes of PU in applications under harsh conditions.展开更多
Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of...Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of CQDs-based memristors is improved by utilizing nitrogen-doping. In contrast, nitrogen-doped CQDs (N-CQDs)-based optoelectronic memristors can be driven with smaller programming voltages (−0.6 to 0.7 V) and exhibit lower powers (78 nW/0.29 µW). The physical mechanism can be attributed to the reversible transition between C–N and C=N with lower binding energy induced by the electric field and the generation of photogenerated carriers by ultraviolet light irradiation, which adjusts the conductivity of the initial N-CQDs to implement resistance switching. Importantly, the convolutional image processing based on various cross kernels is efficiently demonstrated by stable multi-level storage properties. An N-CQDs-based optoelectronic reservoir computing implements impressively high accuracy in both no noise and various noise modes when recognizing the Modified National Institute of Standards and Technology (MNIST) dataset. It illustrates that N-CQDs-based memristors provide a novel strategy for developing artificial vision system with integrated in-memory sensor and computing.展开更多
The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self...The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions.Herein,we design a new hydrogel electrolyte(AF/SH-Hydrogel)with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules,dynamic chemical bonding(disulfide bond),and supramolecular interaction(multi-hydrogen bond)into the polyacrylamide molecular chain.Thanks to the exceptional freeze resistance(84%capacity retention at-20℃)and intrinsic self-healing capabilities(95%capacity retention after 5 cutting/self-healing cycles),the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications.The Zn||AF/SH-Hydrogel||MnO_(2)device offers a near-theoretical specific capacity of 285 m A h g^(-1)at 0.1 A g^(-1)(Coulombic efficiency≈100%),as well as good self-healing capability and mechanical flexibility in an ice bath.This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.展开更多
The exploitation of new green polymerization avenues for the effective synthesis of polymers by reversible-deactivation radical polymerization plays a critical role in pursuing the development of polymeric materials.I...The exploitation of new green polymerization avenues for the effective synthesis of polymers by reversible-deactivation radical polymerization plays a critical role in pursuing the development of polymeric materials.In this work,serials of deep eutectic solvents(DES)with intermolecular-hydrogen-bonding interaction were constructed as catalysts and medium for actuating reversible complexation-mediated polymerization(RCMP)for the first time,yielding methacrylate polymers with high monomer conversion and narrow dispersion molecular weight in both water and oil systems.The mechanism and elementary reaction of RCMP were explored deeply,revealing that the complexation of initiator with DES to generate radicals was a ratecontrolling step and intermolecular-hydrogen-bond was primary factor to influence polymerization rate.Moreover,the insights of density functional theory calculations revealed that negative electrostatic potential ensured nucleophilic capacity.This investigation demonstrated the considerable potential of DES for RCMP,which is anticipated for other polymerization applications as a novel medium mode.展开更多
基金supported by the National Natural Science Foundation of China(Nos.21171040 and 21302019)
文摘A new complex, [Ni2（L）4（H2O）8]（1, L1 = 4-（1H-imidazol-4-yl）benzoic acid）, has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis and PXRD. Complex 1 crystallizes in monoclinic, space group P21/c with α = 22.281（2）, b = 7.3959（7）, c = 24.978（3） ？, β = 90.876（10）, V = 4115.6（7） ？3, Z = 8, C20H22N4O8Ni, Mr = 505.13, Dc = 1.630 g/cm3, μ = 1.001 mm-1, S = 1.080, F（000） = 2096, the final R = 0.452 and wR = 0.1152 for 9380 observed reflections （I 〉 2σ（I））. The result of X-ray diffraction analysis revealed three different kinds of Ni（II） centre mononuclear molecules in the asymmetric unit. The independent mononuclear units are bridged to form a three-dimensional supramolecular polymer by extensive hydrogen bonds and C–H… non-covalent bonding interactions.
基金supported by the National Natural Science Foundation of China(52203064 and 52373061)the China Postdoctoral Science Foundation(2023M732415)+1 种基金the Fundamental Research Funds for the Central Universities(2022SCU12011)the State Key Laboratory of Polymer Materials Engineering,Sichuan University。
文摘Thermal softening is an inevitable process in the physical network.Polyurethane(PU),a typical commercial material,is constructed by physical networks,which undergoes the serious thermal decay on mechanical properties at high temperature.Herein,a physically cross-linked PU with a unique thermal stiffening behavior has been developed by incorporating B–N coordination with reversible B–O bonds.The B–N coordination can significantly improve the mechanical properties of the PU.The reversible B–O bonds(temperature dependent reversible transformation between B–OH and B–O–B)are conducive to constructing more multicoordination macromolecular crosslinking points and more stable B–N coordination bonds at high temperature,endowing the PU with the special thermal stiffening behavior for the first time.Such thermal stiffening behavior compensates for the bond breakage and the network destruction caused by heat,significantly expands the rubbery plateau and delays the entire chain motion of the thermoplastic PU.As a result,the terminal flow occurs at a higher temperature up to 200°C.The modulus retention ratio of the materials is up to 87%even at 145oC,which is much higher than that of the existing PU elastomer with the physical network and even some covalent cross-link PU.Simultaneously,the physical network ensures the recyclability of the PU,and the thermal stiffening behavior is still obtained in recycled PU.This work provides a simple strategy to impart thermal stiffening behavior to the physically crosslinked PU,thereby significantly extending the operating temperature range of thermoplastic PU,which can potentially expand the scopes of PU in applications under harsh conditions.
基金financially supported by the National Key Research and Development Program of China(No.2022YFE0139100)International cooperative research project of Jiangsu province(No.BZ2022008)+3 种基金the National Natural Science Foundation Project of China(No.62175028)Program 111_2.0 in China(No.BP0719013)Leading Technology of Jiangsu Basic Research Plan(No.BK20192003)Postgraduate Research & Practice Innovation Program of Jiangsu Province,the Fundamental Research Funds for the Central Universities(No.KYCX23_0254).
文摘Carbon quantum dots (CQDs) have been used in memristors due to their attractive optical and electronic properties, which are considered candidates for brain-inspired computing devices. In this work, the performance of CQDs-based memristors is improved by utilizing nitrogen-doping. In contrast, nitrogen-doped CQDs (N-CQDs)-based optoelectronic memristors can be driven with smaller programming voltages (−0.6 to 0.7 V) and exhibit lower powers (78 nW/0.29 µW). The physical mechanism can be attributed to the reversible transition between C–N and C=N with lower binding energy induced by the electric field and the generation of photogenerated carriers by ultraviolet light irradiation, which adjusts the conductivity of the initial N-CQDs to implement resistance switching. Importantly, the convolutional image processing based on various cross kernels is efficiently demonstrated by stable multi-level storage properties. An N-CQDs-based optoelectronic reservoir computing implements impressively high accuracy in both no noise and various noise modes when recognizing the Modified National Institute of Standards and Technology (MNIST) dataset. It illustrates that N-CQDs-based memristors provide a novel strategy for developing artificial vision system with integrated in-memory sensor and computing.
基金supported by the link project of the National Natural Science Foundation of China(52002052 and 22209020)the Key Research and Development Project of Science and Technology Department of Sichuan Province(2022YFSY0004)+2 种基金the Opening project of the State Key Laboratory of New Textile Materials and Advanced Processing Technology(FZ2021009)the Natural Science Foundation of Sichuan Province(2023NSFSC0995)the Natural Science Foundation of Hunan Province(2022JJ30227)。
文摘The anti-freezing strategy of hydrogels and their self-healing structure are often contradictory,it is vital to break through the molecular structure to design and construct hydrogels with intrinsic anti-freezing/self-healing for meeting the rapid development of flexible and wearable devices in diverse service conditions.Herein,we design a new hydrogel electrolyte(AF/SH-Hydrogel)with intrinsic anti-freezing/self-healing capabilities by introducing ethylene glycol molecules,dynamic chemical bonding(disulfide bond),and supramolecular interaction(multi-hydrogen bond)into the polyacrylamide molecular chain.Thanks to the exceptional freeze resistance(84%capacity retention at-20℃)and intrinsic self-healing capabilities(95%capacity retention after 5 cutting/self-healing cycles),the obtained AF/SH-Hydrogel makes the zinc||manganese dioxide cell an economically feasible battery for the state-of-the-art applications.The Zn||AF/SH-Hydrogel||MnO_(2)device offers a near-theoretical specific capacity of 285 m A h g^(-1)at 0.1 A g^(-1)(Coulombic efficiency≈100%),as well as good self-healing capability and mechanical flexibility in an ice bath.This work provides insight that can be utilized to develop multifunctional hydrogel electrolytes for application in next generation of self-healable and freeze-resistance smart aqueous energy storage devices.
基金financially supported by the State Key Program of National Natural Science Foundation of China(U21A20313)the Key Program of Qingyuan Innovation Laboratory(00221003)+2 种基金the“111”Program of Fuzhou Universitythe Natural Science Foundation of Fujian Province(2019J05040)the China Postdoctoral Science Foundation(2022M20739)。
文摘The exploitation of new green polymerization avenues for the effective synthesis of polymers by reversible-deactivation radical polymerization plays a critical role in pursuing the development of polymeric materials.In this work,serials of deep eutectic solvents(DES)with intermolecular-hydrogen-bonding interaction were constructed as catalysts and medium for actuating reversible complexation-mediated polymerization(RCMP)for the first time,yielding methacrylate polymers with high monomer conversion and narrow dispersion molecular weight in both water and oil systems.The mechanism and elementary reaction of RCMP were explored deeply,revealing that the complexation of initiator with DES to generate radicals was a ratecontrolling step and intermolecular-hydrogen-bond was primary factor to influence polymerization rate.Moreover,the insights of density functional theory calculations revealed that negative electrostatic potential ensured nucleophilic capacity.This investigation demonstrated the considerable potential of DES for RCMP,which is anticipated for other polymerization applications as a novel medium mode.
