For drop-on-demand(DOD)inkjet printing,stable and single ink droplet fo rmation without satellite dots is the key to improve the print quality.The formation of stable and single droplet is influenced by filament break...For drop-on-demand(DOD)inkjet printing,stable and single ink droplet fo rmation without satellite dots is the key to improve the print quality.The formation of stable and single droplet is influenced by filament break up and the polymer chain’s coil-stretch transition behavior.In this paper,the droplet formation behaviors of polyfluorene(PFO)ink at various driving voltages(V),polymer chain’s coil-stretch transition mechanism and its effects on single ink droplet formation are investigated.It indicates that when 5863 V,Wi>0.5,the PFO molecular chain is stretched because of the high hydrodynamic forces,resulting unwanted satellite droplets.When 55<V<58V,the droplet shrinks into the nozzle,which indicates that the kinetic energy supplied by the deformation of the piezoelectric transducer isn't enough to force thedroplet to be jetted from the nozzle.展开更多
Inkjet printing has emerged as a potential solution processing method for large-area patterned films.During inkjet printing,a single droplet without satellite droplet is required for high-quality film.Herein,we propos...Inkjet printing has emerged as a potential solution processing method for large-area patterned films.During inkjet printing,a single droplet without satellite droplet is required for high-quality film.Herein,we propose a strategy for obtaining a single droplet by adjusting the reduced concentration(c/c^(*),where c^(*)is the critical overlap concentration)in the range of 1.0-1.5.Droplet formation can be categorized into three distinct regimes:(1)c/c^(*)<1.0,satellite droplet;(2)c/c^(*)=1.0-1.5,single droplet;(3)c/c^(*)>2.0,no droplet.Furthermore,an inertial-capillary balance led to the 2/3-power scaling of the minimum radius with time for the solutions of c/c^(*)<1.0.However,for the solutions of c/c^(*)=1.0-1.5,the ligament radius decreased exponentially with time.Moreover,the Weissenberg number was higher than the critical value of 0.5,indicating that the polymer chains underwent coil-stretch transition.The viscoelastic-capillary balance dominated instead of the inertial-capillary balance.The resulting viscoelastic resistance reduced the length of the ligament and increased the velocity difference between the satellite and main droplets.Consequently,a single droplet was formed.In addition,the law can be successfully generalized to various molecular weights,molecular structures and solvents.展开更多
Inkjet printing is a new fabricating method that can realize the precise film deposition. For polymer inks, the coil-stretch transition of polymer chains always impacts the ink droplet formation and a beads-on-a strin...Inkjet printing is a new fabricating method that can realize the precise film deposition. For polymer inks, the coil-stretch transition of polymer chains always impacts the ink droplet formation and a beads-on-a string structure filament is formed, thus generating unwanted satellite droplets. This review provides a short introduction of the dynamic process of the droplet formation. Then fluid theological requirements for a printable polymer ink are summarized. Finally the strain hardening phenomenon of polymer chains in the filament formation and its impact on polymer ink-jetting are discussed. The research of viscoelastic polymer inks shows that rheological parameters and viscoelasticity are two key factors that determine the printability of polymer inks.展开更多
基金the National Natural Science Foundation of China(Nos.51873212,91833306)National Key R&D Program of"Strategic Advanced Electronic Materials"(Nos.2016YFB0401301,2017YFB0404402)。
文摘For drop-on-demand(DOD)inkjet printing,stable and single ink droplet fo rmation without satellite dots is the key to improve the print quality.The formation of stable and single droplet is influenced by filament break up and the polymer chain’s coil-stretch transition behavior.In this paper,the droplet formation behaviors of polyfluorene(PFO)ink at various driving voltages(V),polymer chain’s coil-stretch transition mechanism and its effects on single ink droplet formation are investigated.It indicates that when 5863 V,Wi>0.5,the PFO molecular chain is stretched because of the high hydrodynamic forces,resulting unwanted satellite droplets.When 55<V<58V,the droplet shrinks into the nozzle,which indicates that the kinetic energy supplied by the deformation of the piezoelectric transducer isn't enough to force thedroplet to be jetted from the nozzle.
基金financially supported by the National Natural Science Foundation of China(No.51873212)the CAS-Croucher Funding Scheme for Joint Laboratories:Poly U-CIAC Joint Laboratory(No.121522KYSB20200040)。
文摘Inkjet printing has emerged as a potential solution processing method for large-area patterned films.During inkjet printing,a single droplet without satellite droplet is required for high-quality film.Herein,we propose a strategy for obtaining a single droplet by adjusting the reduced concentration(c/c^(*),where c^(*)is the critical overlap concentration)in the range of 1.0-1.5.Droplet formation can be categorized into three distinct regimes:(1)c/c^(*)<1.0,satellite droplet;(2)c/c^(*)=1.0-1.5,single droplet;(3)c/c^(*)>2.0,no droplet.Furthermore,an inertial-capillary balance led to the 2/3-power scaling of the minimum radius with time for the solutions of c/c^(*)<1.0.However,for the solutions of c/c^(*)=1.0-1.5,the ligament radius decreased exponentially with time.Moreover,the Weissenberg number was higher than the critical value of 0.5,indicating that the polymer chains underwent coil-stretch transition.The viscoelastic-capillary balance dominated instead of the inertial-capillary balance.The resulting viscoelastic resistance reduced the length of the ligament and increased the velocity difference between the satellite and main droplets.Consequently,a single droplet was formed.In addition,the law can be successfully generalized to various molecular weights,molecular structures and solvents.
基金supported by the National Natural Science Foundation of China(Nos. 51473161,21574130)the National Basic Research Program of China (973 Program, No. 2015CB655001)National Key R&D Program of "Strategic Advanced Electronic Materials"(Nos.2016YFB0401301,2016YFB0401100)
文摘Inkjet printing is a new fabricating method that can realize the precise film deposition. For polymer inks, the coil-stretch transition of polymer chains always impacts the ink droplet formation and a beads-on-a string structure filament is formed, thus generating unwanted satellite droplets. This review provides a short introduction of the dynamic process of the droplet formation. Then fluid theological requirements for a printable polymer ink are summarized. Finally the strain hardening phenomenon of polymer chains in the filament formation and its impact on polymer ink-jetting are discussed. The research of viscoelastic polymer inks shows that rheological parameters and viscoelasticity are two key factors that determine the printability of polymer inks.
