'Stepwise-coupling polymerization' (SCP) is a very useful approach for preparing microstructure-controllable ordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular pol...'Stepwise-coupling polymerization' (SCP) is a very useful approach for preparing microstructure-controllable ordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular polymers (TP), and two-dimensional sieve-plate polymers. The novel reactive LPs are important precursors of micro-structure controllable polymers such as 'fishbone-' or 'rowboat-' like mesomorphic polymers and their metal complexes as well as tubular polymers (TPs). They are full of great potential for use as advanced materials.展开更多
Three-arm and four-arm star-like polybutadienes （PBds） were synthesized via the combination of living anionic polymerization and the click coupling method. Kinetic study showed that the click reaction between the az...Three-arm and four-arm star-like polybutadienes （PBds） were synthesized via the combination of living anionic polymerization and the click coupling method. Kinetic study showed that the click reaction between the azido group terminated PBd-t-N3 and the alkyne-containing multifunctional linking reagent was fast and highly efficient. All coupling reactions were fully accomplished within 40 min at 50 ℃ in toluene in the presence of the reducing agent Cu（0）, proven by 1H-NMR, FTIR and GPC measurements. For the coupling reactions between the PBd-t-N3 polymer and dialkyne-containing compound, the final conversion of the coupled PBd-PBd polymer was ca. 97.0%. When a PBd-t-N3 polymer was reacted with trialkyne-containing or tetraalkyne-containing compound, the conversion of three-arm or four-arm PBd was around 95.5% or 87.0%, respectively. Several factors influencing the coupling efficiency were studied, including the molecular weight of the initial PBd-t-N3, arm numbers and the molar ratio of the azido group to the alkynyl group. The results indicated that the conversion of the target products would be promoted when the molecular weight of the PBd-t-N3 was low and the molar ratio of the azido to alkynyl groups was close to 1.展开更多
Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue lig...Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue light after beating at 150 ℃ in air for 24 h, no red-shifted emission was observed by fluorescence spectroscopy.展开更多
The oxidative coupling polymerization of p alkoxyphenols with Mn(acac)2ethylenediamine catalysts was carried out. The polymerization of pmethoxyphenol with the manganese(II) acetylacetonate [Mn(acac)2]N,N’diethylethy...The oxidative coupling polymerization of p alkoxyphenols with Mn(acac)2ethylenediamine catalysts was carried out. The polymerization of pmethoxyphenol with the manganese(II) acetylacetonate [Mn(acac)2]N,N’diethylethylene diamine catalyst in CH2Cl2 at room temperature under an O2 atmosphere afforded a polymer, which mainly consists of the mphenylene unit, whereas the polymer obtained with Mn(acac)2 was rich in the oxyphenylene structure. The polymer yield and regioselectivity were significantly affected by the monomer and catalyst structures. The former catalyst system was also used for the coupling reaction of 2methoxy 4methylphenol. The corresponding carboncar bon coupling product was isolated with a regioselectivity of 95%.展开更多
Soluble green light-emitting poly(9,9-dihexylfluorene-co-fluorenone)was synthesized by solvent-free oxidative coupling polymerization of 9,9-dihexylfluorene in a facile one-step reaction.The polymers were characterize...Soluble green light-emitting poly(9,9-dihexylfluorene-co-fluorenone)was synthesized by solvent-free oxidative coupling polymerization of 9,9-dihexylfluorene in a facile one-step reaction.The polymers were characterized by FT-IR,^1H NMR,^13C NMR,UV-Vis and fluorescence spectroscopy.The region-regular structure of the polymer linking at 2,7'-position on the fluorene moieties was obtained.The FT-IR spectra of the polymers showed fluorenone vibration.The fluorescence spectra of the solid thin film of the polymers displayed green light-emitting,which was emitted from fluorenone moieties produced in the polymerization process.展开更多
An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Su...An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.展开更多
As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by ...As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.展开更多
A kind of novel electroluminescence polymer has been prepared by oxidative-coupling polymerization of N-alkyl carbazole and trans-stilbene. The structure of the copolymers was characterized by elemental analysis, UV-v...A kind of novel electroluminescence polymer has been prepared by oxidative-coupling polymerization of N-alkyl carbazole and trans-stilbene. The structure of the copolymers was characterized by elemental analysis, UV-vis and FTIR spectra. The copolymers have good solubility in chloroform and acetone. Fluorescence spectra showed that these polymers are blue-light emitting materials.展开更多
Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium di...Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium dioxide particles, the titanium dioxide particles were surface-modified with a silicane coupling agent, methacryloylpropyltrimethoxysilicane. Polymer encapsulation in the presence of either modified-titanium dioxide particles or unmodified-titanium dioxide particles was carried out by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrroliclone as stabilizer, and 2, 2＇-azobis（isobutyronitrile） as initiator. The modified-titanium dioxide was analyzed with Fourier-transform infrared spectroscopy（FTIR）, UV-Vis spectrophotometer, thermo-gravimetric analysis and transmission microscope. The polymer encapsulation of modified-titanium dioxide and unmodified-titanium dioxide particles was confirmed with FTIR and transmission electron microscope. Results show that compared with unmodified-titanium dioxide, modified-titanium dioxide is more suitable for preparing inorganic core/orclanic shell composites.展开更多
All-polymer solar cells(all-PSCs)comprising polymer donors and polymer acceptors have attracted considerable attention due to their superior photo-thermal stability and mechanical stretchability[1-3].However,the early...All-polymer solar cells(all-PSCs)comprising polymer donors and polymer acceptors have attracted considerable attention due to their superior photo-thermal stability and mechanical stretchability[1-3].However,the early polymer acceptors exhibit weak absorption coefficients in the longer wavelength region(600-900 nm),limiting the photovoltaic performances of all-PSCs[4-8].In order to address this issue,polymerization of the state-of-the-art A-D-A smallmolecule acceptors(SMAs)viaπ-linkers was proposed to develop new polymer acceptors[9].The polymerized SMAs(PSMAs)can not only inherit the strong near-infrared absorption from the corresponding SMAs,but also have tunable electronic energy levels,thus greatly improving the photovoltaic performances of all-PSCs[10-20].Particularly,the power conversion efficiencies(PCEs)have even surpassed 19%for the all-PSCs based on the Y-series PSMAs and suitable polymer donors[21-24].展开更多
We present here the thermodynamic investigation of in situ cascade polycondensation-coupling ring-opening polymerization(PROP)for three cyclic aromatic ester monomers,i.e.,cyclic oligo(2-methyl-1,3-propylene terephtha...We present here the thermodynamic investigation of in situ cascade polycondensation-coupling ring-opening polymerization(PROP)for three cyclic aromatic ester monomers,i.e.,cyclic oligo(2-methyl-1,3-propylene terephthalate)s(COMPTs),cyclic oligo(neopentylene terephthalate)s(CONTs)and cyclic oligo(2-methyl-2-propyl-1,3-propylene terephthalate)s(COMPPTs).The equibrium monomer to polymer weight ratio in bulk at different polymerization temperatures for each monomer was estimated by the size exclusion chromatography(SEC),and the thermodynamic parameters were estimated by Dainton equation.Quite different from the thermodynamics of aliphatic lactones polymerization,which is an exothermic process with entropy reduction,our results showed the polymerization thermodynamics for three cyclic aromatic ester monomers was a weak exothermic process with slight entropy increment,i.e.,a both enthalpy and entropy driving process.Among them,CONTs showed the largest value of enthalpy change,due to its symmetric dimethyl substitution onβ-position of propandiol segments.展开更多
Highly regioregular, head-to-tail coupled poly（3-octylesterthiophene） was synthesized by the Pd-catalysed oxidative C--H/C--H coupling polycondensation. The regioregularity of polymer products was confirmed by the 1...Highly regioregular, head-to-tail coupled poly（3-octylesterthiophene） was synthesized by the Pd-catalysed oxidative C--H/C--H coupling polycondensation. The regioregularity of polymer products was confirmed by the 1H-NMR technique. Furthermore, the effects of various reaction factors including polymerization temperature, solvents and catalysts etc. on the yield, molecular weight and structural regioregularity of the resultant polymers were systematically studied. The optical, electrochemical and crystallization properties of the resultant P3OET with different HT regioregularities in solution and film state were studied by UV-Vis and fluorescent spectroscopy, cyclic voltammetry and X-ray diffraction （XRD）, resepectively.展开更多
Metamaterials have exotic physical properties that rely on the construction of their underlying architecture.However,the physical properties of conventional mechanical metamaterials are permanently programmed into the...Metamaterials have exotic physical properties that rely on the construction of their underlying architecture.However,the physical properties of conventional mechanical metamaterials are permanently programmed into their periodic interconnect configurations,resulting in their lack of modularity,scalable fabrication,and programmability.Mechanical metamaterials typically exhibit a single extraordinary mechanical property or multiple extraordinary properties coupled together,making it difficult to realize multiple independent extraordinary mechanical properties.Here,the pixel mechanics metamaterials(PMMs)with multifunctional and reprogrammable properties are developed by arraying uncoupled constrained individual modular mechanics pixels(MPs).The MPs enable controlled conversion between two extraordinary mechanical properties(multistability and compression-torsion coupling deformation).Each MP exhibits 32 independent and reversible room temperature programming configurations.In addition,the programmability of metamaterials is further enhanced by shape memory polymer(SMP)and 4D printing,greatly enriching the design freedom.For the PMM consisting of m×n MPs,it has 32(m×n)independent room temperature programming configurations.The application prospects of metamaterials in the vibration isolation device and energy absorption device with programmable performance have been demonstrated.The vibration isolation frequencies of the MP before and after programming were[0 Hz-5.86 Hz],[0 Hz-13.67 Hz and 306.64 Hz-365.23 Hz].The total energy absorption of the developed PMM can be adjusted controllably in the range of 1.01 J-3.91 J.Six standard digital logic gates that do not require sustained external force are designed by controlling the closure between the modules.This design paradigm will facilitate the further development of multifunctional and reprogrammable metamaterials.展开更多
An investigation was made into polystyrene （PS） grafted onto nanometre silicon carbide （SIC） particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency （RF） inductively c...An investigation was made into polystyrene （PS） grafted onto nanometre silicon carbide （SIC） particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency （RF） inductively coupled plasma （ICP） treatment of the nanometre powder. FTIR （Fourier transform infrared spectrum） and XPS （X-ray photoelectron spectroscopy） results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.展开更多
The objective of this paper is to model the size-dependent thermo-mechanical behaviors of a shape memory polymer (SMP) microbeam.Size-dependent constitutive equations,which can capture the size effect of the SMP,are p...The objective of this paper is to model the size-dependent thermo-mechanical behaviors of a shape memory polymer (SMP) microbeam.Size-dependent constitutive equations,which can capture the size effect of the SMP,are proposed based on the modified couple stress theory (MCST).The deformation energy expression of the SMP microbeam is obtained by employing the proposed size-dependent constitutive equation and Bernoulli-Euler beam theory.An SMP microbeam model,which includes the formulations of deflection,strain,curvature,stress and couple stress,is developed by using the principle of minimum potential energy and the separation of variables together.The sizedependent thermo-mechanical and shape memory behaviors of the SMP microbeam and the influence of the Poisson ratio are numerically investigated according to the developed SMP microbeam model.Results show that the size effects of the SMP microbeam are significant when the dimensionless height is small enough.However,they are too slight to be necessarily considered when the dimensionless height is large enough.The bending flexibility and stress level of the SMP microbeam rise with the increasing dimensionless height,while the couple stress level declines with the increasing dimensionless height.The larger the dimensionless height is,the more obvious the viscous property and shape memory effect of the SMP microbeam are.The Poisson ratio has obvious influence on the size-dependent behaviors of the SMP microbeam.The paper provides a theoretical basis and a quantitatively analyzing tool for the design and analysis of SMP micro-structures in the field of biological medicine,microelectronic devices and micro-electro-mechanical system (MEMS) self-assembling.展开更多
文摘'Stepwise-coupling polymerization' (SCP) is a very useful approach for preparing microstructure-controllable ordered network polymers, including soluble one-dimensional ladderlike polymers (LP) and tubular polymers (TP), and two-dimensional sieve-plate polymers. The novel reactive LPs are important precursors of micro-structure controllable polymers such as 'fishbone-' or 'rowboat-' like mesomorphic polymers and their metal complexes as well as tubular polymers (TPs). They are full of great potential for use as advanced materials.
基金financially supported by the National Natural Science Foundation of China(Nos.51233005,21004060 and 51073149)
文摘Three-arm and four-arm star-like polybutadienes （PBds） were synthesized via the combination of living anionic polymerization and the click coupling method. Kinetic study showed that the click reaction between the azido group terminated PBd-t-N3 and the alkyne-containing multifunctional linking reagent was fast and highly efficient. All coupling reactions were fully accomplished within 40 min at 50 ℃ in toluene in the presence of the reducing agent Cu（0）, proven by 1H-NMR, FTIR and GPC measurements. For the coupling reactions between the PBd-t-N3 polymer and dialkyne-containing compound, the final conversion of the coupled PBd-PBd polymer was ca. 97.0%. When a PBd-t-N3 polymer was reacted with trialkyne-containing or tetraalkyne-containing compound, the conversion of three-arm or four-arm PBd was around 95.5% or 87.0%, respectively. Several factors influencing the coupling efficiency were studied, including the molecular weight of the initial PBd-t-N3, arm numbers and the molar ratio of the azido group to the alkynyl group. The results indicated that the conversion of the target products would be promoted when the molecular weight of the PBd-t-N3 was low and the molar ratio of the azido to alkynyl groups was close to 1.
文摘Dihexylfluorene and N-butylcarbazole were copolymerized by solid-state oxidative coupling polymerization in the presence of anhydrous FeCl3 at room temperature. The solid-state films of the copolymers emitted blue light after beating at 150 ℃ in air for 24 h, no red-shifted emission was observed by fluorescence spectroscopy.
文摘The oxidative coupling polymerization of p alkoxyphenols with Mn(acac)2ethylenediamine catalysts was carried out. The polymerization of pmethoxyphenol with the manganese(II) acetylacetonate [Mn(acac)2]N,N’diethylethylene diamine catalyst in CH2Cl2 at room temperature under an O2 atmosphere afforded a polymer, which mainly consists of the mphenylene unit, whereas the polymer obtained with Mn(acac)2 was rich in the oxyphenylene structure. The polymer yield and regioselectivity were significantly affected by the monomer and catalyst structures. The former catalyst system was also used for the coupling reaction of 2methoxy 4methylphenol. The corresponding carboncar bon coupling product was isolated with a regioselectivity of 95%.
基金Supported by the National Natural Science Foundation of China(20274031)
文摘Soluble green light-emitting poly(9,9-dihexylfluorene-co-fluorenone)was synthesized by solvent-free oxidative coupling polymerization of 9,9-dihexylfluorene in a facile one-step reaction.The polymers were characterized by FT-IR,^1H NMR,^13C NMR,UV-Vis and fluorescence spectroscopy.The region-regular structure of the polymer linking at 2,7'-position on the fluorene moieties was obtained.The FT-IR spectra of the polymers showed fluorenone vibration.The fluorescence spectra of the solid thin film of the polymers displayed green light-emitting,which was emitted from fluorenone moieties produced in the polymerization process.
基金supported by the National Natural Foundation of China(21422306,21203165,21403193)the Fundamental Research Funds for the Central Universities(2015XZZX004-04)~~
文摘An efficient catalyst system based on a Pd-metalated porous organic polymer bearing phenanthroline ligands was designed and synthesized.This catalyst was applied to various C–C bond-forming reactions,including the Suzuki,Heck and Sonogashira couplings,and afforded the corresponding products while exhibiting excellent activities and selectivities.More importantly,this catalyst can be readily recycled.These features show that such catalysts have significant potential applications in the future.
基金the National Natural Science Foundation of China(No.51773046)the Fundamental Research Funds for the Central Universities,the School of Materials Science and Engineering,Shaanxi Normal Universitythe Project of Key Laboratory of Organic Synthesis of Jiangsu Province,College of Chemistry Chemical Engineering and Materials Science,Soochow University。
文摘As the high calibre candidate of lightweight and flexible solar cells,polymer solar cells(PSCs)have made tremendous progress in recent years.However,the active photovoltaic materials in PSCs are mainly synthesized by metal-mediated coupling reaction requiring harsh reaction conditions,multiple-step synthesis,and cumbersome purification,which is not cost-efficient and may bring toxicity concerns.It is not favorable to the production of photovoltaic polymers and PSC devices on a large scale,and therefore unsuitable for the PSCs industrialization.Direct arylation coupling reaction via aromatic C―H bonds activation enables the synthesis of conjugated polymers under mild conditions and simultaneously reduces synthetic steps,difficulty,and toxic reaction byproducts.This review provides an overview of the history of preparing representative photovoltaic polymers utilized in PSCs through direct arylation reactions and discusses the activity and selectivity of C―H bonds in typical building blocks under different reaction conditions.Especially,the impact of direct arylation condition on defect formation and photovoltaic performance of the photovoltaic polymers is addressed and compared with conventional Stille coupling methods.
基金National Natural Science Foundation of ChinaEducation Ministry of China.
文摘A kind of novel electroluminescence polymer has been prepared by oxidative-coupling polymerization of N-alkyl carbazole and trans-stilbene. The structure of the copolymers was characterized by elemental analysis, UV-vis and FTIR spectra. The copolymers have good solubility in chloroform and acetone. Fluorescence spectra showed that these polymers are blue-light emitting materials.
基金Supported by National High Technology Research and Development Program of China (863 Program) (No. 2004AA302010) and Natural Science Foundation of Tianjin (No. 043186411) .
文摘Surface modification of nanometer titanium dioxide particles and effect of preparing TiO2/P （St-co-DVB） composites by dispersion polymerization are described. To introduce vinyl group onto the surface of titanium dioxide particles, the titanium dioxide particles were surface-modified with a silicane coupling agent, methacryloylpropyltrimethoxysilicane. Polymer encapsulation in the presence of either modified-titanium dioxide particles or unmodified-titanium dioxide particles was carried out by dispersion polymerization of styrene, divinylbenzene in ethanol medium with polyvinylpyrroliclone as stabilizer, and 2, 2＇-azobis（isobutyronitrile） as initiator. The modified-titanium dioxide was analyzed with Fourier-transform infrared spectroscopy（FTIR）, UV-Vis spectrophotometer, thermo-gravimetric analysis and transmission microscope. The polymer encapsulation of modified-titanium dioxide and unmodified-titanium dioxide particles was confirmed with FTIR and transmission electron microscope. Results show that compared with unmodified-titanium dioxide, modified-titanium dioxide is more suitable for preparing inorganic core/orclanic shell composites.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB0520102)the National Key R&D Program of China(2024YFA1209600)+1 种基金the National Natural Science Foundation of China(22173108)the Youth Innovation Promotion Association CAS(2023037).
文摘All-polymer solar cells(all-PSCs)comprising polymer donors and polymer acceptors have attracted considerable attention due to their superior photo-thermal stability and mechanical stretchability[1-3].However,the early polymer acceptors exhibit weak absorption coefficients in the longer wavelength region(600-900 nm),limiting the photovoltaic performances of all-PSCs[4-8].In order to address this issue,polymerization of the state-of-the-art A-D-A smallmolecule acceptors(SMAs)viaπ-linkers was proposed to develop new polymer acceptors[9].The polymerized SMAs(PSMAs)can not only inherit the strong near-infrared absorption from the corresponding SMAs,but also have tunable electronic energy levels,thus greatly improving the photovoltaic performances of all-PSCs[10-20].Particularly,the power conversion efficiencies(PCEs)have even surpassed 19%for the all-PSCs based on the Y-series PSMAs and suitable polymer donors[21-24].
基金financially supported by the National Natural Science Foundation of China (Nos. 21474067, 21774090)Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘We present here the thermodynamic investigation of in situ cascade polycondensation-coupling ring-opening polymerization(PROP)for three cyclic aromatic ester monomers,i.e.,cyclic oligo(2-methyl-1,3-propylene terephthalate)s(COMPTs),cyclic oligo(neopentylene terephthalate)s(CONTs)and cyclic oligo(2-methyl-2-propyl-1,3-propylene terephthalate)s(COMPPTs).The equibrium monomer to polymer weight ratio in bulk at different polymerization temperatures for each monomer was estimated by the size exclusion chromatography(SEC),and the thermodynamic parameters were estimated by Dainton equation.Quite different from the thermodynamics of aliphatic lactones polymerization,which is an exothermic process with entropy reduction,our results showed the polymerization thermodynamics for three cyclic aromatic ester monomers was a weak exothermic process with slight entropy increment,i.e.,a both enthalpy and entropy driving process.Among them,CONTs showed the largest value of enthalpy change,due to its symmetric dimethyl substitution onβ-position of propandiol segments.
基金financially supported by the National Natural Science Foundation of China(Nos.21604063 and 51373122)China Postdoctoral Science Foundation(No.2016M591392)
文摘Highly regioregular, head-to-tail coupled poly（3-octylesterthiophene） was synthesized by the Pd-catalysed oxidative C--H/C--H coupling polycondensation. The regioregularity of polymer products was confirmed by the 1H-NMR technique. Furthermore, the effects of various reaction factors including polymerization temperature, solvents and catalysts etc. on the yield, molecular weight and structural regioregularity of the resultant polymers were systematically studied. The optical, electrochemical and crystallization properties of the resultant P3OET with different HT regioregularities in solution and film state were studied by UV-Vis and fluorescent spectroscopy, cyclic voltammetry and X-ray diffraction （XRD）, resepectively.
基金the financial support provided by the National Key R&D Program of China(2022YFB3805700)the National Natural Science Foundation of China(Grant Nos.12072094 and 12172106)+2 种基金the China Postdoctoral Science Foundation(Grant No.2023M730869)the Heilongjiang Natural Science Foundation Joint Guidance Project(Grant No.LH2023A004)the Postdoctoral Fellowship Program of CPSF(Grant No.GZB20230959)。
文摘Metamaterials have exotic physical properties that rely on the construction of their underlying architecture.However,the physical properties of conventional mechanical metamaterials are permanently programmed into their periodic interconnect configurations,resulting in their lack of modularity,scalable fabrication,and programmability.Mechanical metamaterials typically exhibit a single extraordinary mechanical property or multiple extraordinary properties coupled together,making it difficult to realize multiple independent extraordinary mechanical properties.Here,the pixel mechanics metamaterials(PMMs)with multifunctional and reprogrammable properties are developed by arraying uncoupled constrained individual modular mechanics pixels(MPs).The MPs enable controlled conversion between two extraordinary mechanical properties(multistability and compression-torsion coupling deformation).Each MP exhibits 32 independent and reversible room temperature programming configurations.In addition,the programmability of metamaterials is further enhanced by shape memory polymer(SMP)and 4D printing,greatly enriching the design freedom.For the PMM consisting of m×n MPs,it has 32(m×n)independent room temperature programming configurations.The application prospects of metamaterials in the vibration isolation device and energy absorption device with programmable performance have been demonstrated.The vibration isolation frequencies of the MP before and after programming were[0 Hz-5.86 Hz],[0 Hz-13.67 Hz and 306.64 Hz-365.23 Hz].The total energy absorption of the developed PMM can be adjusted controllably in the range of 1.01 J-3.91 J.Six standard digital logic gates that do not require sustained external force are designed by controlling the closure between the modules.This design paradigm will facilitate the further development of multifunctional and reprogrammable metamaterials.
文摘An investigation was made into polystyrene （PS） grafted onto nanometre silicon carbide （SIC） particles. In our experiment, the grafting polymerization reaction was induced by a radio frequency （RF） inductively coupled plasma （ICP） treatment of the nanometre powder. FTIR （Fourier transform infrared spectrum） and XPS （X-ray photoelectron spectroscopy） results reveal that PS is grafted onto the surface of silicon carbide powder. An analysis is presented on the effectiveness of this approach as a function of plasma operating variables including the plasma treating power, treating time, and grafting reaction temperature and time.
基金Project supported by the National Key Research and Development Program of China(No.2017YFC0307604)the Talent Foundation of China University of Petroleum(No.Y1215042)the Graduate Innovation Program of China University of Petroleum(East China)(No.YCX2019084)
文摘The objective of this paper is to model the size-dependent thermo-mechanical behaviors of a shape memory polymer (SMP) microbeam.Size-dependent constitutive equations,which can capture the size effect of the SMP,are proposed based on the modified couple stress theory (MCST).The deformation energy expression of the SMP microbeam is obtained by employing the proposed size-dependent constitutive equation and Bernoulli-Euler beam theory.An SMP microbeam model,which includes the formulations of deflection,strain,curvature,stress and couple stress,is developed by using the principle of minimum potential energy and the separation of variables together.The sizedependent thermo-mechanical and shape memory behaviors of the SMP microbeam and the influence of the Poisson ratio are numerically investigated according to the developed SMP microbeam model.Results show that the size effects of the SMP microbeam are significant when the dimensionless height is small enough.However,they are too slight to be necessarily considered when the dimensionless height is large enough.The bending flexibility and stress level of the SMP microbeam rise with the increasing dimensionless height,while the couple stress level declines with the increasing dimensionless height.The larger the dimensionless height is,the more obvious the viscous property and shape memory effect of the SMP microbeam are.The Poisson ratio has obvious influence on the size-dependent behaviors of the SMP microbeam.The paper provides a theoretical basis and a quantitatively analyzing tool for the design and analysis of SMP micro-structures in the field of biological medicine,microelectronic devices and micro-electro-mechanical system (MEMS) self-assembling.
