In-fiber structured particles and filament array have been recently emerging,providing unique advantages of feasible fabrication,diverse structures and sophisticated functionalities.This review will focus on the progr...In-fiber structured particles and filament array have been recently emerging,providing unique advantages of feasible fabrication,diverse structures and sophisticated functionalities.This review will focus on the progress of this topic mainly from the perspective of fluid instabilities.By suppressing the capillary instability,the uniform layered structures down to nanometers are attained with the suitable materials selection.On the other hand,by utilizing capillary instability via post-drawing thermal treatment,the unprecedent structured particles can be designed with multimaterials for multifunctional fiber devices.Moreover,an interesting filamentation instability of a stretching viscous sheet has been identified during thermal drawing,resulting in an array of filaments.This review may inspire more future work to produce versatile devices for fiber electronics,either at a single fiber level or in large-scale fabrics and textiles,simply by manipulating and controlling fluid instabilities.展开更多
The linear growth of Ftayleigh-Taylor instability （FtTI） of two superimposed finite-thickness fluids in a gravita- tional field is investigated analytically. Coupling evolution equations for perturbation on the uppe...The linear growth of Ftayleigh-Taylor instability （FtTI） of two superimposed finite-thickness fluids in a gravita- tional field is investigated analytically. Coupling evolution equations for perturbation on the upper, middle and lower interfaces of the two stratified fluids are derived. The growth rate of the RTI and the evolution of the amplitudes of perturbation on the three interfaces are obtained by solving the coupling equations. It is found that the finite-thickness fluids reduce the growth rate of perturbation on the middle interface. However, the finite-thickness effect plays an important role in perturbation growth even for the thin layers which will cause more severe RTI growth. Finally, the dependence of the interface position under different initial conditions are discussed in some detail.展开更多
Electrospinning experiments are performed by using a set of experimental apparatus, a stroboscopic system is adopted for capturing instantaneous images of the cone- jet configuration. The cone and the jet of aqueous s...Electrospinning experiments are performed by using a set of experimental apparatus, a stroboscopic system is adopted for capturing instantaneous images of the cone- jet configuration. The cone and the jet of aqueous solutions of polyethylene oxide （PEO） are formed from an orifice of a capillary tube under the electric field. The viscoelastic con- stitutive relationship of the PEO solution is measured and discussed. The phenomena owing to the jet instability are described, five flow modes and corresponding structures are obtained with variations of the fluid flow rate Q, the electric potential U and the distance h from the orifice of the cap- illary tube to the collector. The flow modes of the cone-jet configuration involves the steady bending mode, the rotat- ing bending mode, the swinging rotating mode, the blurring bending mode and the branching mode. Regimes in the Q-U plane of the flow modes are also obtained. These results may provide the fundamentals to predict the operating conditions expected in practical applications.展开更多
基金Guangming Tao acknowledges the National Natural Science Foundation of China(Grant No.61875064)WNLO Man-Machine Lab Fund,WNLO Innovation Fund and HUST Innovation Fund(Grant No.2172018KFYXKJC021)+3 种基金State Key Laboratory for Modification of Chemical Fibers and Polymer Materials,Donghua University.Lei Wei acknowledges the support by the Singapore Ministry of Education Academic Research Fund Tier 2(MOE2015-T2-2-010)Singapore Ministry of Education Academic Research Fund Tier 1(MOE2019-T1-001-103 and MOE2019-T1-001-111)the EEE Ignition Research Grant.Daosheng Deng is indebted to Prof.Yoel Fink,Prof.Steven Johnson,and Prof.Howard Stone for the guidance and discussions on the topic of in-fiber nanostructures generated by fluid instabilities,and the collaboration with Prof.Ayman Abouraddyacknowledges the funding support by the National Young Thousand Talent Program in China and startup from Fudan University.
文摘In-fiber structured particles and filament array have been recently emerging,providing unique advantages of feasible fabrication,diverse structures and sophisticated functionalities.This review will focus on the progress of this topic mainly from the perspective of fluid instabilities.By suppressing the capillary instability,the uniform layered structures down to nanometers are attained with the suitable materials selection.On the other hand,by utilizing capillary instability via post-drawing thermal treatment,the unprecedent structured particles can be designed with multimaterials for multifunctional fiber devices.Moreover,an interesting filamentation instability of a stretching viscous sheet has been identified during thermal drawing,resulting in an array of filaments.This review may inspire more future work to produce versatile devices for fiber electronics,either at a single fiber level or in large-scale fabrics and textiles,simply by manipulating and controlling fluid instabilities.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11275031,11475034,11575033 and 11274026the National Basic Research Program of China under Grant No 2013CB834100
文摘The linear growth of Ftayleigh-Taylor instability （FtTI） of two superimposed finite-thickness fluids in a gravita- tional field is investigated analytically. Coupling evolution equations for perturbation on the upper, middle and lower interfaces of the two stratified fluids are derived. The growth rate of the RTI and the evolution of the amplitudes of perturbation on the three interfaces are obtained by solving the coupling equations. It is found that the finite-thickness fluids reduce the growth rate of perturbation on the middle interface. However, the finite-thickness effect plays an important role in perturbation growth even for the thin layers which will cause more severe RTI growth. Finally, the dependence of the interface position under different initial conditions are discussed in some detail.
基金supported by the National Natural Science Foundation of China Project (11002139)the China Postdoctoral Science Foundation (20100470854)
文摘Electrospinning experiments are performed by using a set of experimental apparatus, a stroboscopic system is adopted for capturing instantaneous images of the cone- jet configuration. The cone and the jet of aqueous solutions of polyethylene oxide （PEO） are formed from an orifice of a capillary tube under the electric field. The viscoelastic con- stitutive relationship of the PEO solution is measured and discussed. The phenomena owing to the jet instability are described, five flow modes and corresponding structures are obtained with variations of the fluid flow rate Q, the electric potential U and the distance h from the orifice of the cap- illary tube to the collector. The flow modes of the cone-jet configuration involves the steady bending mode, the rotat- ing bending mode, the swinging rotating mode, the blurring bending mode and the branching mode. Regimes in the Q-U plane of the flow modes are also obtained. These results may provide the fundamentals to predict the operating conditions expected in practical applications.
