http://www.dspace.cam.ac.uk:80/handle/1810/238991 Thu, 23 May 2013 01:37:14 GMT 2013-05-23T01:37:14Z http://www.dspace.cam.ac.uk:80/handle/1810/243845 Title: How PEDOT:PSS solutions produce satellite-free inkjets Authors: Hoath, S.D.; Jung, S.-J.; Hsiao, W.-K.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243845 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243628 Title: The matching of polymer solution fast filament stretching, relaxation and break up experimental results with 1D and 2D numerical viscoelastic simulation Authors: Vadillo, D.C.; Tembely, M.; Morrison, N.F.; Harlen, O.G.; Mackley, M.R.; Soucemarianadin, A. Tue, 31 Jul 2012 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243628 2012-07-31T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243431 Title: Aerodynamic effects in ink-jet printing on a moving web Authors: Hsiao, W.-K.; Hoath, S.D.; Martin, G.D.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243431 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243430 Title: Velocity Profiles in a Cylindrical Liquid Jet by Reconstructed Velocimetry Authors: Castrejon-Pita, J.R.; Hoath, S.D.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243430 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243429 Title: High speed shadowgraphy for the study of liquid drops Authors: Castrejon-Pita, J.R.; Castrejon-Garcia, R.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243429 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243428 Title: Self-similar Breakup of Near-inviscid Fluids Authors: Castrejon-Pita, J.R.; Castrejon-Pita, A.A.; Hinch, E.J.; Lister, J.R.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243428 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243404 Title: Breakup of Liquid Filaments Authors: Castrejon-Pita, Alfonso A.; Castrejon-Pita, J.R.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243404 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243374 Title: Drying and Deposition of Picolitre Droplets of Colloidal Suspensions in Binary Solvent Mixtures Authors: Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243374 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243373 Title: Regimes of polymer behaviour in drop-on-demand ink-jetting Authors: Hoath, S.D.; Hutchings, I.M.; Harlen, O.G.; McIIroy, C.; Morrison, N.F. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243373 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243372 Title: Evaporation of Picolitre Droplets on Surfaces with a Range of Wettabilities and Thermal Conductivities Authors: Talbot, E.L.; Berson, A.; Brown, P.S.; Bain, C.D. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243372 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243358 Title: Jetting behaviour of polymer solutions in drop-on-demand inkjet printing Authors: Hoath, S.D.; Harlen, O.G.; Hutchings, I.M. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243358 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243357 Title: Microsecond relaxation processes in shear and extensional flows of weakly elastic polymer solutions Authors: Vadillo, D.C.; Mathues, W.; Clasen, C. Sun, 01 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243357 2012-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/243356 Title: Impact of picolitre droplets on superhydrophobic surfaces with ultra-low spreading ratios Authors: Brown, P.S.; Berson, A.; Talbot, E.L.; Wood, T.J.; Schofield, W.C.E.; Bain, C.D.; Badyal, J.P.S. Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/243356 2011-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/241108 Title: The matching of a “one-dimensional” numerical simulation and experiment results for low viscosity Newtonian and non-Newtonian fluids during fast filament stretching and subsequent break-up Authors: Tembely, M.; Vadillo, D.; Mackley, M.R.; Soucemarianadin, A. Mon, 23 Jan 2012 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/241108 2012-01-23T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/240700 Title: Imbibition dynamics of nano-particulate ink-jet drops on micro-porous media Authors: Hsiao, W.-K.; Hoath, S.D.; Martin, G.D.; Hutchings, I.M.; Chilton, N.B.; Jones, S. Abstract: Ink-jet printing of nano-metallic colloidal fluids on to porous media such as coated papers has become a viable method to produce conductive tracks for low-cost, disposable printed electronic devices. However, the formation of well-defined and functional tracks on an absorbing surface is controlled by the drop imbibition dynamics in addition to the well-studied post-impact drop spreading behavior. This study represents the first investigation of the realtime imbibition of ink-jet deposited nano-Cu colloid drops on to coated paper substrates. In addition, the same ink was deposited on to a non-porous polymer surface as a control substrate. By using high-speed video imaging to capture the deposition of ink-jet drops, the time-scales of drop spreading and imbibition were quantified and compared with model predictions. The influences of the coating pore size on the bulk absorption rate and nano-Cu particle distribution have also been studied. Tue, 31 May 2011 23:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/240700 2011-05-31T23:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/239170 Title: Inkjet printing of non-Newtonian fluids Authors: Morrison, N.F.; Harlen, O.G. Abstract: Jet breakup is strongly affected by fluid rheology. In particular,small amounts of polymer can cause substantially different breakup dynamics compared to a Newtonian jet, influencing in-flight fragmentation and detachment from the nozzle. Significant concentrations may also impede jettability. Furthermore, most commercial and industrial inks are inherently colloidal due to the presence of pigment and other additives. Fluids containing a particulate phase are normally shear-thinning and so may have a different characteristic viscosity within the nozzle compared to the ejected ligament. We have developed numerical simulations using a Lagrangian finite element method that captures the free surface automatically, and admits a variety of viscosity dependences, e.g. on the local shear rate (generalized Newtonian fluid) or on the particle concentration (Krieger-Dougherty type models), in addition to several viscoelastic models for polymeric fluids. This method has been benchmarked against experimental data for Newtonian jets. Appropriate rheological models are discussed, and results are presented alongside comparisons with experimental work. Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/239170 2011-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/239169 Title: The effect of inkjet ink composition on rheology and jetting behaviour Authors: Vadillo, D.C.; Hoath, S.D.; Hsiao, W.-K.; Mackley, M.R. Abstract: This work presents recent results on the way linear and non linear viscoelastic properties of the fluids affect the jetting mechanism. Recent progress on quantitative characterising both high frequency linear (LVE) and non-linear (NLVE) viscoelasticity of fluids allows fluids to be assessed for their jettability before using such materials in a DoD print head. In term of linear viscoelastic measurements, the Piezo Axial Vibrator (PAV) was used to probe the rheology of the fluids on a frequency range between 10Hz and 10000Hz. A filament stretching apparatus, called the “Cambridge Trimaster”, was used in combination with high speed cinematography, to characterize the fluids high speed stretching and break-up behaviour. The series of fluids investigated here consist in dilutions of mono disperse polystyrene with different molecular weight (110, 210, 306 and 488 kg/mol respectively) diluted in diethyl phthalate. The choice of polymer weights and concentrations were chosen to match both the complex viscosity and the LVE. However, non linear rheological data experiments exhibit differences in the fluid relaxation time and filament break-up mechanism. Ultra-high speed cinematography of DoD jetting events were correlated with filament break-up experiments and demonstrated that fluid rheology provides valuable information on the jetting quality of the fluids. Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/239169 2011-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/239168 Title: Holographic Measurement of Drop-on-Demand Drops in Flight Authors: Martin, G. D.; Castrejon-Pita, J. R.; Hutchings, I. M. Abstract: The analysis of images of ink drops in flight can provide information about jet straightness, drop velocity and volume. However trade-offs between field of view, optical and digital resolution and other factors such as depth of field and optical distortion, limit the accuracy and amount of information available from a single image. In-line, digital holograms of drops in flight can capture information from fields of view at least as large as the area of the digital sensor. Using mathematical reconstruction techniques particularly suited to sparse, small objects of regular geometry the accuracy of measurement can potentially be submicrometer on drop position and diameter. This paper describes our experimental apparatus, hologram reconstruction techniques and the results of experiments on imaging drops. We also discuss techniques to improve the accuracy of the technique in the direction of the optical axis. Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/239168 2011-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/239167 Title: Jetting, In-Nozzle Meniscus Motion and Nozzle-Plate Flooding in an Industrial Drop-on-Demand Print Head Authors: Hsiao, W.-K.; Hoath, S.D.; Martin, G.D.; Hutchings, I.M. Abstract: The state of the ink film at and near the nozzles of a drop-ondemand(DoD) print head during jetting has a direct impact on printing performance and reliability. We have developed highspeed imaging apparatus and analytical techniques to investigate the ink film dynamics on an industrial print head nozzle-plate in real-time. In addition to a direct correlation between the jet emergence velocity and drive voltage, drive-dependent variations in the oscillation of the ink meniscus in adjacent nozzles were also observed. Using a ray-tracing model to analyze the meniscus shape, the meniscus oscillations for both printing and nonprinting nozzles were found to be complex and involve elements such as pre-oscillation and high-order surface waves. The flooding of non-firing nozzles, deliberately caused by the application of maximum drive voltage to a neighboring nozzle, has been recorded and analyzed dynamically. The build-up of fluid in an annulus around the nozzle (flooding rate) has been characterized and compared with models for the net ink flow through the nozzle. Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/239167 2011-01-01T00:00:00Z http://www.dspace.cam.ac.uk:80/handle/1810/239166 Title: Dependence of drop speed on nozzle diameter, viscosity and drive amplitude in drop-on-demand ink-jet printing Authors: Hoath, S.D.; Hsiao, W.-K.; Jung, S.; Martin, G.D.; Hutchings, I.M. Abstract: Results of recent experiments and numerical simulations are presented, which have been used to establish empirical rules for the dependence of drop speed on nozzle diameter and drive amplitude for Newtonian and non-Newtonian fluids printed with a range of different ink-jet print-head technologies. Experiments were carried out with Xaar, MicroFab and Spectra Dimatix print heads and with solutions of polystyrene in diethyl phthalate as model fluids. These results are compared with predictions from recent numerical codes developed by collaborators in the University of Leeds, and from simple models for drop-on-demand fluid jetting resulting from physical laws Sat, 01 Jan 2011 00:00:00 GMT http://www.dspace.cam.ac.uk:80/handle/1810/239166 2011-01-01T00:00:00Z