Regulating the surface instability of thin film/substrate structures has been successfully applied to prepare new ductile electronic devices.However,such electronic devices need to be subjected to external loads durin...Regulating the surface instability of thin film/substrate structures has been successfully applied to prepare new ductile electronic devices.However,such electronic devices need to be subjected to external loads during operation,which can easily induce delamination of the thin-film electronic device from the substrate.This study aims to investigate the instability characteristics of hard films on flexible substrate surfaces from theoretical analysis and numerical simulation perspectives.Considering finite-thickness substrates,this paper establishes theoretical models for pure bending,bent wrinkle,partial delamination,and total delamination buckling of film/substrate structures based on the nonlinear Euler–Bernoulli beam theory and the principle of minimum energy;then the effects of material and geometric parameters of the structure,interfacial adhesion strength,and pre-strain on the evolutionary path of the four patterns are discussed.The study results show that:the greater Young’s modulus of the substrate is,the larger the parameter region where partial delamination of the film/substrate structure occurs,and the smaller the parameter region where bent wrinkle occurs.By varying Young’s modulus,thickness of the film and substrate,interfacial adhesion coefficient,and pre-strain,the buckling pattern of the structure can be predicted and regulated.The parametric design intervals for each pattern are summarized in the phase diagram.The results of this paper provide theoretical support for the design and reliability evaluation of flexible electronic devices.展开更多
Due to negative effects of conventional fluorinated surfactants with long perfluorocarbon chain(C_(x)F_(2x+1),x≥7)like perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),these conventional long perfluoro...Due to negative effects of conventional fluorinated surfactants with long perfluorocarbon chain(C_(x)F_(2x+1),x≥7)like perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),these conventional long perfluorocarbon chain surfactants have been restricted in many industrial applications.Nowadays,their potential non-bioaccumulable alternatives have been developed to meet the requirements of environmental sustainable development.In this paper,the recent advances of potential non-bioaccumulable fluorinated surfactants with different fluorocarbon chain structures,including the short perfluorocarbon chain,the branched fluorocarbon chain,and the fluorocarbon chain with weak points,are reviewed from the aspects of synthesis processes,properties,and structure-activity relationships.And their applications in emulsion polymerization of fluorinated olefins,handling membrane proteins,and leather manufacture also are summarized.Furthermore,the challenges embedded in the current non-bioaccumulable fluorinated surfactants are also highlighted and discussed with the hope to provide a valuable reference for the prosperous development of fluorinated surfactants.展开更多
Mixing hydrocarbon surfactants with fluorocarbon surfactants is still an important strategy to improve the economic benefits and performances of fluorocarbon surfactants and expand their range of application.Herein,we...Mixing hydrocarbon surfactants with fluorocarbon surfactants is still an important strategy to improve the economic benefits and performances of fluorocarbon surfactants and expand their range of application.Herein,we prepared a novel kind of hydrocarbon-fluorocarbon surfactant mixtures via mixing a cationic surfactant,cetyltrimethylammonium bromide(CTAB),with a tri-block nonionic short-chain fluorocarbon surfactant(F_(9)EG_(13)F_(9))in aqueous solution.The results showed that adding a small CTAB amount to F_(9)EG_(13)F_(9)(the molar fraction of CTAB in the mixture(x_(1))was 0.2)could greatly reduce its critical micelle concentrations(cmc)from 0.408mmol/L to 0.191 mmol/L.At this x_(1),the contact angle of the mixture was the minimum(57.7°)at 100 s on polytetrafluoroethylene film,which was even lower than that of F_(9)EG_(13)F_(9).Besides,CTAB/F_(9)EG_(13)F_(9) mixtures possessed better colloidal stability and solubilization ability toward hydrophobic dye(SudanІ)than F_(9)EG_(13)F_(9).The outstanding performances of binary surfactant mixtures benefited from the non-ideal mixing and strong synergistic effect evidence that CTAB/F_(9)EG_(13)F_(9) surfactant mixtures could be used in practical applications instead of individual F_(9)EG_(13)F_(9),thereby reducing the used cost of F_(9)EG_(13)F_(9).展开更多
基金funded by the Practice and Innovation Funds for Graduate Students of Northwestern Polytechnical University(Grant No.2021201712).
文摘Regulating the surface instability of thin film/substrate structures has been successfully applied to prepare new ductile electronic devices.However,such electronic devices need to be subjected to external loads during operation,which can easily induce delamination of the thin-film electronic device from the substrate.This study aims to investigate the instability characteristics of hard films on flexible substrate surfaces from theoretical analysis and numerical simulation perspectives.Considering finite-thickness substrates,this paper establishes theoretical models for pure bending,bent wrinkle,partial delamination,and total delamination buckling of film/substrate structures based on the nonlinear Euler–Bernoulli beam theory and the principle of minimum energy;then the effects of material and geometric parameters of the structure,interfacial adhesion strength,and pre-strain on the evolutionary path of the four patterns are discussed.The study results show that:the greater Young’s modulus of the substrate is,the larger the parameter region where partial delamination of the film/substrate structure occurs,and the smaller the parameter region where bent wrinkle occurs.By varying Young’s modulus,thickness of the film and substrate,interfacial adhesion coefficient,and pre-strain,the buckling pattern of the structure can be predicted and regulated.The parametric design intervals for each pattern are summarized in the phase diagram.The results of this paper provide theoretical support for the design and reliability evaluation of flexible electronic devices.
基金National Natural Science Foundation of China(No.22078207)Sichuan Science and Technology Program(No.2020YFG0069)Fundamental Research Funds for the Central Universities(China).
文摘Due to negative effects of conventional fluorinated surfactants with long perfluorocarbon chain(C_(x)F_(2x+1),x≥7)like perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),these conventional long perfluorocarbon chain surfactants have been restricted in many industrial applications.Nowadays,their potential non-bioaccumulable alternatives have been developed to meet the requirements of environmental sustainable development.In this paper,the recent advances of potential non-bioaccumulable fluorinated surfactants with different fluorocarbon chain structures,including the short perfluorocarbon chain,the branched fluorocarbon chain,and the fluorocarbon chain with weak points,are reviewed from the aspects of synthesis processes,properties,and structure-activity relationships.And their applications in emulsion polymerization of fluorinated olefins,handling membrane proteins,and leather manufacture also are summarized.Furthermore,the challenges embedded in the current non-bioaccumulable fluorinated surfactants are also highlighted and discussed with the hope to provide a valuable reference for the prosperous development of fluorinated surfactants.
基金National Natural Science Foundation of China(No.22078207)Sichuan Science and Technology Program(2021ZHCG0042)Fundamental Research Funds for the Central Universities(China).
文摘Mixing hydrocarbon surfactants with fluorocarbon surfactants is still an important strategy to improve the economic benefits and performances of fluorocarbon surfactants and expand their range of application.Herein,we prepared a novel kind of hydrocarbon-fluorocarbon surfactant mixtures via mixing a cationic surfactant,cetyltrimethylammonium bromide(CTAB),with a tri-block nonionic short-chain fluorocarbon surfactant(F_(9)EG_(13)F_(9))in aqueous solution.The results showed that adding a small CTAB amount to F_(9)EG_(13)F_(9)(the molar fraction of CTAB in the mixture(x_(1))was 0.2)could greatly reduce its critical micelle concentrations(cmc)from 0.408mmol/L to 0.191 mmol/L.At this x_(1),the contact angle of the mixture was the minimum(57.7°)at 100 s on polytetrafluoroethylene film,which was even lower than that of F_(9)EG_(13)F_(9).Besides,CTAB/F_(9)EG_(13)F_(9) mixtures possessed better colloidal stability and solubilization ability toward hydrophobic dye(SudanІ)than F_(9)EG_(13)F_(9).The outstanding performances of binary surfactant mixtures benefited from the non-ideal mixing and strong synergistic effect evidence that CTAB/F_(9)EG_(13)F_(9) surfactant mixtures could be used in practical applications instead of individual F_(9)EG_(13)F_(9),thereby reducing the used cost of F_(9)EG_(13)F_(9).
