Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this ...Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this study,novel poly(ε-caprolactone)(PCL)-poly(2-vinyl)ethylene glycol(PVEG)copolymers bearing multi-pendant vinyl groups is synthesized by branched-selective allylic etherification polymerization of vinylethylene carbonate(VEC)with linear and tetra-arm PCLs under a synergistic catalysis of palladium complex and boron reagent.Facile thiol-ene photo-click reaction of PCL-PVEG copolymers with multifunctional thiols can rapidly access a serious crosslinked SMPs with high shape memory performance.The thermal properties,mechanical properties and response temperature of the obtained SMPs are tunable by the variation of PCL prepolymers,vinyl contents and functionality of thiols.Moreover,high elastic modulus in the rubbery plateau region can be maintained effectively owing to high-density topological networks of the PCL materials.In addition,the utility of the present SMPs is further demonstrated by the post-functionalization via thiol-ene photo-click chemistry.展开更多
Reconfigurable metamaterials significantly expand the application scenarios and operating frequency range of metamaterials,making them promising candidates for use in smart tunable device.Here,we propose and experimen...Reconfigurable metamaterials significantly expand the application scenarios and operating frequency range of metamaterials,making them promising candidates for use in smart tunable device.Here,we propose and experimentally demonstrate that integrating metamaterial design principles with the intrinsic features of natural materials can engineer thermal smart metadevices.Tunable extraordinary optical transmission like(EOT-like)phenomena have been achieved in the microwave regime using shape memory alloy(SMA).The strongly localized fields generated by designed metadevices,combined with the intense interference of incident waves,enhance transmission through subwavelength apertures.Leveraging the temperature-responsive properties of SMA,the morphology of the metadevice can be recontructed,thereby modifying its response to electromagnetic waves.The experiments demonstrated control over the operating frequency and transmission amplitude of EOT-like behavior,achieving a maximum transmission enhancement factor of 126.Furthermore,the metadevices with modular design enable the realization of multiple functions with independent control have been demonstrated.The proposed SMA-based metamaterials offer advantages in terms of miniaturization,easy processing,and high design flexibility.They may have potential applications in microwave devices requiring temperature control,such as sensing and monitoring.展开更多
Shape memory polymers,with intrinsic enhanced strength and high thermal stability,are highly demanded in aerospace,engineering manufacturing,and spatial structures.In this paper,we develop a series of thermoplastic sh...Shape memory polymers,with intrinsic enhanced strength and high thermal stability,are highly demanded in aerospace,engineering manufacturing,and spatial structures.In this paper,we develop a series of thermoplastic shape memory poly(ether ether ketone)s(PEEKs)for the first time,achieving an excellent shape memory ability,high strength,and great thermal stability via a condensation polymerization.Through tuning the proportion of different bisphenol monomers,the flexibility of molecular main chains is adjusted,resulting in the regulation of transition temperature and mechanical performances.Synthesized PEEKs possess the tunable T_(g) from 143.3°C to 178.6°C,the enhanced tensile strength from 48.4 to 65.1 MPa,and Young’s modulus from 0.45 to 1.8 GPa,in addition to the excellent heat-triggered shape memory effect,as indicated by high recovery ratio(94%–98.9%)and fixity ratio(over 99.5%).Furthermore,after incorporating the magnetocaloric Fe_(3)O_(4) particles,the composites exhibit remotely noncontact magnetic-triggered shape memory behaviors(Fe_(3)O_(4) content over 10 wt%).These synthesized T_(g) tunable shape memory PEEKs and the composites have wide utilization potential in fields of engineering and aerospace structures,owing to the excellent mechanical properties,thermal stability,unique programmable deformation ability,and remote actuation.展开更多
Thermoresponsive luminescent organic materials have great potential for intelligent optical devices,but their applicability remains limited due to formidable challenges in achieving tunable response temperature and di...Thermoresponsive luminescent organic materials have great potential for intelligent optical devices,but their applicability remains limited due to formidable challenges in achieving tunable response temperature and different colors.In this study,we developed a thermoresponsive polymer/lanthanide ion(Ln^(3+))complex system,enabling precise regulation of luminescence color and response temperature.The polymer was synthesized via copolymerization of acrylamide(Am)with 6-(3-(2-(methacryloyloxy)ethyl)ureido)picolinate(MAUP).The MAUP unit incorporates ligands capable of coordinating with Ln^(3+)and functions as an“antenna”,absorbing incident light and efficiently transferring energy to Ln^(3+),leading to diverse luminescent emissions.The thermoresponsive property of the poly(Am-co-MAUP)/Ln^(3+)complexes,based on the synergy of ionic coordination and hydrogen bonding,imparts the precise regulation of luminescence with temperature.The response temperature of the poly(Amco-MAUP)/Ln^(3+)complexes can be finely tuned by various factors synergistically,including polymer composition and Ln^(3+)concentrations.Moreover,these thermoresponsive luminescent complexes enable potential applications in multi-level information encryption and visual temperature sensing.展开更多
Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limi...Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limited their wide applications.This work reports a novel composite hydrogel consisting of hydroxypropyl cellulose,polyacrylic acid,and carbon quantum dots with intriguing features of tunable transition temperature and enhanced switching speed.The composite hydrogel demonstrated flexible tunability in transition temperature by controlling the hydrogen ion concentration and a fast response speed by dopping with carbon dots for efficient photothermal conversion.The building energy simulation was carried out to investigate the impacts of transition temperature variations and solar regulations on the space cooling/heating loads under different climate conditions,revealing the necessity of tunability of both transition temperature and solar transmittance in thermochromic smart windows.This novel design of thermochromic composite hydrogel provides insight into theoretical and experimental support for future adaptive building envelopes.展开更多
基金financially supported by the National Natural Science Foundation of China(No.22171182)Sichuan Tianfu Emei Plan.
文摘Control crosslink network and chain connectivity are essential to develop shape memory polymers(SMPs)with high shape memory capabilities,adjustable response temperature,and satisfying mechanistical properties.In this study,novel poly(ε-caprolactone)(PCL)-poly(2-vinyl)ethylene glycol(PVEG)copolymers bearing multi-pendant vinyl groups is synthesized by branched-selective allylic etherification polymerization of vinylethylene carbonate(VEC)with linear and tetra-arm PCLs under a synergistic catalysis of palladium complex and boron reagent.Facile thiol-ene photo-click reaction of PCL-PVEG copolymers with multifunctional thiols can rapidly access a serious crosslinked SMPs with high shape memory performance.The thermal properties,mechanical properties and response temperature of the obtained SMPs are tunable by the variation of PCL prepolymers,vinyl contents and functionality of thiols.Moreover,high elastic modulus in the rubbery plateau region can be maintained effectively owing to high-density topological networks of the PCL materials.In addition,the utility of the present SMPs is further demonstrated by the post-functionalization via thiol-ene photo-click chemistry.
基金the financial support from the National Key R&D Program of China (Nos. 2023YFB3811400, 2022YFB3806000)the National Natural Science Foundation of China (Nos. 12074314, 52202370, 52332006)+3 种基金the Aeronautical Science Foundation of China (No. 20230018053007)the Science and Technology New Star Program of Shaanxi Province (No. 2023KJXX-148)the Fundamental Research Funds for the Central UniversitiesChina Postdoctoral Science Foundation (No. 2023T160359)
文摘Reconfigurable metamaterials significantly expand the application scenarios and operating frequency range of metamaterials,making them promising candidates for use in smart tunable device.Here,we propose and experimentally demonstrate that integrating metamaterial design principles with the intrinsic features of natural materials can engineer thermal smart metadevices.Tunable extraordinary optical transmission like(EOT-like)phenomena have been achieved in the microwave regime using shape memory alloy(SMA).The strongly localized fields generated by designed metadevices,combined with the intense interference of incident waves,enhance transmission through subwavelength apertures.Leveraging the temperature-responsive properties of SMA,the morphology of the metadevice can be recontructed,thereby modifying its response to electromagnetic waves.The experiments demonstrated control over the operating frequency and transmission amplitude of EOT-like behavior,achieving a maximum transmission enhancement factor of 126.Furthermore,the metadevices with modular design enable the realization of multiple functions with independent control have been demonstrated.The proposed SMA-based metamaterials offer advantages in terms of miniaturization,easy processing,and high design flexibility.They may have potential applications in microwave devices requiring temperature control,such as sensing and monitoring.
基金supported by the Heilongjiang Touyan Innovation Team Program。
文摘Shape memory polymers,with intrinsic enhanced strength and high thermal stability,are highly demanded in aerospace,engineering manufacturing,and spatial structures.In this paper,we develop a series of thermoplastic shape memory poly(ether ether ketone)s(PEEKs)for the first time,achieving an excellent shape memory ability,high strength,and great thermal stability via a condensation polymerization.Through tuning the proportion of different bisphenol monomers,the flexibility of molecular main chains is adjusted,resulting in the regulation of transition temperature and mechanical performances.Synthesized PEEKs possess the tunable T_(g) from 143.3°C to 178.6°C,the enhanced tensile strength from 48.4 to 65.1 MPa,and Young’s modulus from 0.45 to 1.8 GPa,in addition to the excellent heat-triggered shape memory effect,as indicated by high recovery ratio(94%–98.9%)and fixity ratio(over 99.5%).Furthermore,after incorporating the magnetocaloric Fe_(3)O_(4) particles,the composites exhibit remotely noncontact magnetic-triggered shape memory behaviors(Fe_(3)O_(4) content over 10 wt%).These synthesized T_(g) tunable shape memory PEEKs and the composites have wide utilization potential in fields of engineering and aerospace structures,owing to the excellent mechanical properties,thermal stability,unique programmable deformation ability,and remote actuation.
基金supported by the Ningbo Youth Leading Talent Project(2024QL020)the National Natural Science Foundation of China(52373118 and 22075154)+1 种基金the“Mechanics+”Interdisciplinary Top Innovative Youth Fund Project of Ningbo University(LJ2024006)the Ningbo Major Science and Technology Project(2024Z205)。
文摘Thermoresponsive luminescent organic materials have great potential for intelligent optical devices,but their applicability remains limited due to formidable challenges in achieving tunable response temperature and different colors.In this study,we developed a thermoresponsive polymer/lanthanide ion(Ln^(3+))complex system,enabling precise regulation of luminescence color and response temperature.The polymer was synthesized via copolymerization of acrylamide(Am)with 6-(3-(2-(methacryloyloxy)ethyl)ureido)picolinate(MAUP).The MAUP unit incorporates ligands capable of coordinating with Ln^(3+)and functions as an“antenna”,absorbing incident light and efficiently transferring energy to Ln^(3+),leading to diverse luminescent emissions.The thermoresponsive property of the poly(Am-co-MAUP)/Ln^(3+)complexes,based on the synergy of ionic coordination and hydrogen bonding,imparts the precise regulation of luminescence with temperature.The response temperature of the poly(Amco-MAUP)/Ln^(3+)complexes can be finely tuned by various factors synergistically,including polymer composition and Ln^(3+)concentrations.Moreover,these thermoresponsive luminescent complexes enable potential applications in multi-level information encryption and visual temperature sensing.
基金supported by the National Key Research and Development Program of China(2023YFC3806300)the Postgraduate Research&Practice Innovation Program of Jiangsu Province(KYCX23_1485)
文摘Thermoresponsive hydrogels have been designed for smart windows to dynamically modulate solar radiation,but their inherent drawbacks of long response time and imperfectly matched phase transition temperature have limited their wide applications.This work reports a novel composite hydrogel consisting of hydroxypropyl cellulose,polyacrylic acid,and carbon quantum dots with intriguing features of tunable transition temperature and enhanced switching speed.The composite hydrogel demonstrated flexible tunability in transition temperature by controlling the hydrogen ion concentration and a fast response speed by dopping with carbon dots for efficient photothermal conversion.The building energy simulation was carried out to investigate the impacts of transition temperature variations and solar regulations on the space cooling/heating loads under different climate conditions,revealing the necessity of tunability of both transition temperature and solar transmittance in thermochromic smart windows.This novel design of thermochromic composite hydrogel provides insight into theoretical and experimental support for future adaptive building envelopes.
