To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.Howeve...To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.展开更多
An effective design strategy for preparing highly transparent polyimide film with low dielectric constant is presented.The key to the strategy is to simultaneously introduce meta-substituted structure and trifluoromet...An effective design strategy for preparing highly transparent polyimide film with low dielectric constant is presented.The key to the strategy is to simultaneously introduce meta-substituted structure and trifluoromethyl in polymer chains.By using this design strategy,a highly transparent polyimide film with low-k was synthesized from 3,5-diaminobenzotrifluoride(m-TFPDA)and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)through a two-step method.The obtained m-TFPDA/6FDA(CPI)film(~30 pm)possesses high optical transparency(λ_(cutoff)=334 nm,T_(450nm)=85.26%,Haze=0.31)and is close to colorless(L^(*)=96.03,a^(*)=-0.34,b^(*)=2.12,yellow index=3.96).The intrinsic k and dielectric loss value of the film are 2.27 and 0.0013 at 10 kHz,respectively.More importantly,such low dielectric performance could remain stable up to 280℃,and the film shows a low moisture rate(~0.51%),which helps to maintain the low-k property stability in different humid environments.Meanwhile,the film also shows good thermal stability and mechanical properties,with a glass transition temperature(T_(g))of 296℃and the 5 wt%decomposition temperature(T_(d,s%))of 522℃under N_(2).The tensile strength and tensile modulus of the film are 85.1 MPa and 1.96 GPa,respectively.In addition,the film is soluble in common solvents,which allows simple solution processing and low-cost,continuous roll-to-roll processes.This design strategy is beneficial to improving the transparency,lightening yellow color,lowering the dielectric constant and meanwhile maintaining the comprehensive properties of polyimide films,which is mainly due to the introduced meta-substituted and trifluoromethyl structures effectively inhibiting the transfer of charge transfer complex(CTC)effects and increasing the free volume of film.This design strategy could also be extended to other high-performance polymer systems.展开更多
The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinat...The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinated colorless polyimides(CPIs)materials using 2,5-substituted m-phenylenediamine diamine monomers and 1,2,4,5-cyclohexanetetracarboxylic dianhydride(CHDA).We systematically studied the effects of fluorinated group substitutions on the thermal,mechanical,optical and dielectric properties of CPI films.The introduction of alicyclic CHDA dianhydride affords high transparency and low yellowness,while the 2,5-substituted m-phenylenediamine diamines offer the CPIs with quite low birefringence as well as high glass transition temperatures.A particular CHDA/o3FBDA film with simple chemical structure stands out,exhibiting well-balanced overall properties.展开更多
A series of transparent crosslinked colorless polyimide(CPI)films are prepared from 3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA),2,2'-bis(trifluoro-methyl)benzidine(TFMB),and 4,4'-oxydianiline(O...A series of transparent crosslinked colorless polyimide(CPI)films are prepared from 3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA),2,2'-bis(trifluoro-methyl)benzidine(TFMB),and 4,4'-oxydianiline(ODA)by thermal imidization,incorporating varying contents of 2,2'-(1,3-phenylene)bis(2-oxazoline)(1,3-PBO)as the crosslinking agent.Following the incorporation of the crosslinking structure,the CPI films show good optical transparency(approximately 85%winthin visible light range),enhanced glass transition temperature(from 325℃to 341℃),and improved thermal stability,and tensile strength.Notably,compared with the pristine uncrosslinked CPI,these crosslinked CPI films significantly increase in elongation at break(from 5.4%to 44.2%).Furthermore,the new approach ensures that crosslinked CPIs improve heat resistance and mechanical properties,while avoiding the embrittlement of materials.This study also offeres straightforward preparation methods for optically transparent crosslinked polyimides without additional processing steps.All these results make this approach can effectively improve the competitive performance of the CPI films for potential applications in microelectronic and optoelectronic fields.展开更多
Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the t...Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.展开更多
In this paper, a new wireless measuring method for colorless liquid level measurement was presented, based on latest CLC100 liquid level sensor and Powercast wireless sensor development kit. The wireless system is div...In this paper, a new wireless measuring method for colorless liquid level measurement was presented, based on latest CLC100 liquid level sensor and Powercast wireless sensor development kit. The wireless system is divided into two parts, level measurement and data transmission part as well as data receiving and display part. First part included the capacitive liquid level sensor CLC100 and the wireless senor board. CLC100 sensor was used for liquid level measurement. Wireless sensor kit from Powercast Corporation included one wireless sensor board, which was used for signal transmission. A built-in PIC microcontroller was embedded in the transmission module, for the purpose of processing and data transmitting. Due to CLC100 sensor’s output voltage exceeding the sensor board’s input limitation, a voltage convertor was designed to connect the sensor and the wireless sensor board. The final results were voltages corresponding to the liquid level, and were processed by an independent PIC development board, and then sent to PC’s hyper terminal via serial-port by this PIC microcontroller. Experiments showed that this wireless sensor node prototype worked well.展开更多
Energy loss through windows significantly contributes to building energy consumption,highlighting the demand for transparent thermal-insulating materials.Colorless,transparent polyimide(PI)aerogels are a promising cla...Energy loss through windows significantly contributes to building energy consumption,highlighting the demand for transparent thermal-insulating materials.Colorless,transparent polyimide(PI)aerogels are a promising class of candidate materials,but their development has been hindered by the challenging balance among optical transparency,color quality,and thermomechanical properties.Herein,we report a colorless and transparent PI aerogel through molecular engineering of the polymer network.Optimized aerogel(PI-2)with exceptional combined properties has been fabricated via copolymerization of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA),4,4′-oxydianiline(ODA),and p-phenylenediamine(p-PDA),cross-linked with 1,3,5-tris(4-aminophenoxy)benzene(TAB)and processed via supercritical drying.The introduction of p-PDA enhances molecular chain rigidity and optimizes the nanoporous structure(peak pore size of 19.1 nm),simultaneously reducing light scattering and suppressing heat transfer.Compared to control samples without p-PDA(PI-1)or with 2,2′-dimethyl-4,4′-diaminobiphenyl(DMBZ,PI-3),PI-2 achieves colorlessness and high optical transmittance(57.1%at 800 nm)while maintaining superior thermal and mechanical performance.This work provides a strategy for developing colorless,transparent PI aerogels with potential applications for energy-efficient windows and optoelectronic devices.展开更多
The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and ...The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.展开更多
聚酰亚胺(PI)因其卓越的力学性能、热稳定性及易加工性,在空间太阳能电池柔性盖片领域展现出巨大的应用潜力。然而,PI分子间及分子内存在的电荷转移络合物(CTC)效应限制了其光学透过率的进一步提升。作者采用化学亚胺法成功合成了PI,并...聚酰亚胺(PI)因其卓越的力学性能、热稳定性及易加工性,在空间太阳能电池柔性盖片领域展现出巨大的应用潜力。然而,PI分子间及分子内存在的电荷转移络合物(CTC)效应限制了其光学透过率的进一步提升。作者采用化学亚胺法成功合成了PI,并进一步利用电子束蒸镀技术,通过光学匹配减少界面反射,制备了高透明PI复合薄膜(nAR/CPI)。该复合薄膜经过能量分别为1 MeV和100 ke V,注量分别为6.7×10^(14)e·cm^(-2)和2×10^(15)e·cm^(-2)的电子辐照后,其光学、力学及热学性能未见明显衰退,表现出优异的耐辐照性能,在空间太阳电池柔性盖片领域展现出良好的应用前景。展开更多
Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorles...Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorless aesthetic.It resembles clothing that has come from the future.The secret behind this captivating design lies in"SOLAMENTR■"developed by Sumitomo Metal Mining Co.,Ltd.展开更多
基金supported by the National Natural Science Foundation of China(No.22276139)the Shanghai’s Municipal State-owned Assets Supervision and Administration Commission(No.2022028).
文摘To better understand the migration behavior of plastic fragments in the environment,development of rapid non-destructive methods for in-situ identification and characterization of plastic fragments is necessary.However,most of the studies had focused only on colored plastic fragments,ignoring colorless plastic fragments and the effects of different environmental media(backgrounds),thus underestimating their abundance.To address this issue,the present study used near-infrared spectroscopy to compare the identification of colored and colorless plastic fragments based on partial least squares-discriminant analysis(PLS-DA),extreme gradient boost,support vector machine and random forest classifier.The effects of polymer color,type,thickness,and background on the plastic fragments classification were evaluated.PLS-DA presented the best and most stable outcome,with higher robustness and lower misclassification rate.All models frequently misinterpreted colorless plastic fragments and its background when the fragment thickness was less than 0.1mm.A two-stage modeling method,which first distinguishes the plastic types and then identifies colorless plastic fragments that had been misclassified as background,was proposed.The method presented an accuracy higher than 99%in different backgrounds.In summary,this study developed a novel method for rapid and synchronous identification of colored and colorless plastic fragments under complex environmental backgrounds.
基金supported by the Scientific Research Inn ovation Plan of Sha nghai Education Commission(No.2019-01-07-00-03-E0001)the National Natural Science Foundation of China(Nos.21774019,21975040,51903038)+2 种基金the Program of Shanghai Academic Research Leader(No.18XD1400100)the Natural Science Foundation of Shanghai(No.18ZR1400600)the DHU Distinguished Young Professor Program.
文摘An effective design strategy for preparing highly transparent polyimide film with low dielectric constant is presented.The key to the strategy is to simultaneously introduce meta-substituted structure and trifluoromethyl in polymer chains.By using this design strategy,a highly transparent polyimide film with low-k was synthesized from 3,5-diaminobenzotrifluoride(m-TFPDA)and 4,4'-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)through a two-step method.The obtained m-TFPDA/6FDA(CPI)film(~30 pm)possesses high optical transparency(λ_(cutoff)=334 nm,T_(450nm)=85.26%,Haze=0.31)and is close to colorless(L^(*)=96.03,a^(*)=-0.34,b^(*)=2.12,yellow index=3.96).The intrinsic k and dielectric loss value of the film are 2.27 and 0.0013 at 10 kHz,respectively.More importantly,such low dielectric performance could remain stable up to 280℃,and the film shows a low moisture rate(~0.51%),which helps to maintain the low-k property stability in different humid environments.Meanwhile,the film also shows good thermal stability and mechanical properties,with a glass transition temperature(T_(g))of 296℃and the 5 wt%decomposition temperature(T_(d,s%))of 522℃under N_(2).The tensile strength and tensile modulus of the film are 85.1 MPa and 1.96 GPa,respectively.In addition,the film is soluble in common solvents,which allows simple solution processing and low-cost,continuous roll-to-roll processes.This design strategy is beneficial to improving the transparency,lightening yellow color,lowering the dielectric constant and meanwhile maintaining the comprehensive properties of polyimide films,which is mainly due to the introduced meta-substituted and trifluoromethyl structures effectively inhibiting the transfer of charge transfer complex(CTC)effects and increasing the free volume of film.This design strategy could also be extended to other high-performance polymer systems.
基金supported by the Natural Science Foundation of Guangdong Province(No.2022A1515010125)the Key-Area Research and Development Program of Guangdong Province(No.2020B010182002)+5 种基金the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515110543)the R&D Program of Guangzhou(No.2023A04J1577)the Major Program of National Natural Science Foundation of China(No.51890871)the Recruitment Program of Guangdong(No.2016ZT06C322)the 111 Project(No.B18023)Jiangsu Key Laboratory of Advanced Functional Polymer Design and Application at Soochow University.
文摘The development of optical films with high transparency,high thermal resistance and low birefringence remains a challenge in the flexible display industry.In this work,we designed and synthesized a series of fluorinated colorless polyimides(CPIs)materials using 2,5-substituted m-phenylenediamine diamine monomers and 1,2,4,5-cyclohexanetetracarboxylic dianhydride(CHDA).We systematically studied the effects of fluorinated group substitutions on the thermal,mechanical,optical and dielectric properties of CPI films.The introduction of alicyclic CHDA dianhydride affords high transparency and low yellowness,while the 2,5-substituted m-phenylenediamine diamines offer the CPIs with quite low birefringence as well as high glass transition temperatures.A particular CHDA/o3FBDA film with simple chemical structure stands out,exhibiting well-balanced overall properties.
文摘A series of transparent crosslinked colorless polyimide(CPI)films are prepared from 3,3',4,4'-biphenyltetracarboxylic dianhydride(BPDA),2,2'-bis(trifluoro-methyl)benzidine(TFMB),and 4,4'-oxydianiline(ODA)by thermal imidization,incorporating varying contents of 2,2'-(1,3-phenylene)bis(2-oxazoline)(1,3-PBO)as the crosslinking agent.Following the incorporation of the crosslinking structure,the CPI films show good optical transparency(approximately 85%winthin visible light range),enhanced glass transition temperature(from 325℃to 341℃),and improved thermal stability,and tensile strength.Notably,compared with the pristine uncrosslinked CPI,these crosslinked CPI films significantly increase in elongation at break(from 5.4%to 44.2%).Furthermore,the new approach ensures that crosslinked CPIs improve heat resistance and mechanical properties,while avoiding the embrittlement of materials.This study also offeres straightforward preparation methods for optically transparent crosslinked polyimides without additional processing steps.All these results make this approach can effectively improve the competitive performance of the CPI films for potential applications in microelectronic and optoelectronic fields.
基金Natural Science Foundation of Hebei Province(China),Grant/Award Numbers:B2020203013,B2021203016Science and Technology Project of Hebei Education Department(China),Grant/Award Number:QN2020137+3 种基金Cultivation Project for Basic Research Innovation of Yanshan University(China),Grant/Award Number:2021LGZD015Subsidy for Hebei Key Laboratory of Applied Chemistry after Operation Performance(China),Grant/Award Number:22567616HNatural Science Foundation of Heilongjiang Province(China),Grant/Award Number:LH2022B025Fundamental Research Funds for the Provincial Universities of Heilongjiang Province(China),Grant/Award Number:KYYWF10236190104。
文摘Colorless‐to‐black switching has attracted widespread attention for smart windows and multifunctional displays because they are more useful to control solar energy.However,it still remains a challenge owing to the tremendous difficulties in the design of completely reverse absorptions in transmissive and colored states.Herein,we report on an electrochemical device that can switch between colorless and black by using the electrochemical process of hybrid organic–inorganic perovskite MAPbBr_(3),which shows a high integrated contrast ratio of up to 73%from 400 to 800 nm.The perovskite solution can be used as the active layer to assemble the device,showing superior transmittance over the entire visible region in neutral states.By applying an appropriate voltage,the device undergoes reversible switching between colorless and black,which is attributed to the formation of lead and Br_(2)in the redox reaction induced by the electron transfer process in MAPbBr_(3).In addition,the contrast ratio can be modulated over the entire visible region by changing the concentration and the applied voltage.These results contribute toward gaining an insightful understanding of the electrochemical process of perovskites and greatly promoting the development of switchable devices.
文摘In this paper, a new wireless measuring method for colorless liquid level measurement was presented, based on latest CLC100 liquid level sensor and Powercast wireless sensor development kit. The wireless system is divided into two parts, level measurement and data transmission part as well as data receiving and display part. First part included the capacitive liquid level sensor CLC100 and the wireless senor board. CLC100 sensor was used for liquid level measurement. Wireless sensor kit from Powercast Corporation included one wireless sensor board, which was used for signal transmission. A built-in PIC microcontroller was embedded in the transmission module, for the purpose of processing and data transmitting. Due to CLC100 sensor’s output voltage exceeding the sensor board’s input limitation, a voltage convertor was designed to connect the sensor and the wireless sensor board. The final results were voltages corresponding to the liquid level, and were processed by an independent PIC development board, and then sent to PC’s hyper terminal via serial-port by this PIC microcontroller. Experiments showed that this wireless sensor node prototype worked well.
基金supported by the National Key Research and Development Program of China(2022YFA1203600)the National Natural Science Foundation of China(52233006)+2 种基金the Natural Science Foundation of Jiangsu Province(BK20240205 and BK20241632)the Jiangsu Province Postdoctoral Science Foundation(2024ZB852)the China Postdoctoral Science Foundation(2025T180044)and the Young Elite Scientists Sponsorship Program by CAST(2024QNRC001).
文摘Energy loss through windows significantly contributes to building energy consumption,highlighting the demand for transparent thermal-insulating materials.Colorless,transparent polyimide(PI)aerogels are a promising class of candidate materials,but their development has been hindered by the challenging balance among optical transparency,color quality,and thermomechanical properties.Herein,we report a colorless and transparent PI aerogel through molecular engineering of the polymer network.Optimized aerogel(PI-2)with exceptional combined properties has been fabricated via copolymerization of 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA),4,4′-oxydianiline(ODA),and p-phenylenediamine(p-PDA),cross-linked with 1,3,5-tris(4-aminophenoxy)benzene(TAB)and processed via supercritical drying.The introduction of p-PDA enhances molecular chain rigidity and optimizes the nanoporous structure(peak pore size of 19.1 nm),simultaneously reducing light scattering and suppressing heat transfer.Compared to control samples without p-PDA(PI-1)or with 2,2′-dimethyl-4,4′-diaminobiphenyl(DMBZ,PI-3),PI-2 achieves colorlessness and high optical transmittance(57.1%at 800 nm)while maintaining superior thermal and mechanical performance.This work provides a strategy for developing colorless,transparent PI aerogels with potential applications for energy-efficient windows and optoelectronic devices.
基金financially supported by the National Key R&D Program of China(No.2023YFB3812400)the National Natural Science Foundation of China(No.51890871)the GJYC Program of Guangzhou(No.2024D02J0004)。
文摘The development of high-performance transparent substrates is critical for next-generation flexible electronic devices.Herein,we designed two novel meta-substituted diamines incorporating trifluoromethyl(―CF_(3))and methyl(―CH_(3))groups to synthesize colorless copolyimide(CPI)films via copolymerization with 4,4′-(hexafluoroisopropylidene)diphthalic anhydride(6FDA)/3,3′,4,4′-biphenyltetracarboxylic dianhydride(BPDA).The combination of meta-substituted architecture and substituents enables the simultaneous attainment of an ultralow dielectric constant(D_k)and high transparency.The meta-substitution geometry and electronic effects of―CF_(3)/―CH_(3) effectively suppressed charge-transfer complex(CTC)formation,expanded fractional free volume(FFV),and restricted π-electron conjugation,as validated by DFT calculations and wide-angle X-ray diffraction(WAXD)analysis.The optimized CPI film(PIA_(1)-6FDA/BPDA(10/0))achieved outstanding transmittance(T_(450)=88.15%),ultralow dielectric constant(D_(k)=2.08 at 1 k Hz),and minimal dielectric loss(D_(f)=0.0012),while maintaining robust thermal stability(T_(d5%)>523℃)and mechanical strength(σ=87.5 MPa).This work establishes a molecular engineering strategy to concurrently enhance the optical and dielectric properties,positioning meta-substituted CPIs as promising candidates for transparent flexible devices.
文摘聚酰亚胺(PI)因其卓越的力学性能、热稳定性及易加工性,在空间太阳能电池柔性盖片领域展现出巨大的应用潜力。然而,PI分子间及分子内存在的电荷转移络合物(CTC)效应限制了其光学透过率的进一步提升。作者采用化学亚胺法成功合成了PI,并进一步利用电子束蒸镀技术,通过光学匹配减少界面反射,制备了高透明PI复合薄膜(nAR/CPI)。该复合薄膜经过能量分别为1 MeV和100 ke V,注量分别为6.7×10^(14)e·cm^(-2)和2×10^(15)e·cm^(-2)的电子辐照后,其光学、力学及热学性能未见明显衰退,表现出优异的耐辐照性能,在空间太阳电池柔性盖片领域展现出良好的应用前景。
文摘Have we ever seen such a shocking garment in the fashion industry?A down jacket that claims to be one but uses absolutely no down,yet possesses remarkable heating and insulating properties,all designed with a colorless aesthetic.It resembles clothing that has come from the future.The secret behind this captivating design lies in"SOLAMENTR■"developed by Sumitomo Metal Mining Co.,Ltd.
