Inkjet printing of weakly elastic polymer solutions

Hoath, Stephen D., Vadillo, Damien C., Harlen, Oliver G., McIlroy, Claire, Morrison, Neil F., Hsiao, Wen-Kai, Tuladhar, Tri R., Jung, Sungjune, Martin, Graham D. and Hutchings, Ian M. (2014) Inkjet printing of weakly elastic polymer solutions. Journal of Non-Newtonian Fluid Mechanics, 205 . pp. 1-10. ISSN 0377-0257

Full content URL: http://doi.org/10.1016/j.jnnfm.2014.01.002

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Inkjet printing of weakly elastic polymer solutions
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Abstract

Fluid assessment methods, requiring small volumes and avoiding the need for jetting, are particularly useful in the design of functional fluids for inkjet printing applications. With the increasing use of complex (rather than Newtonian) fluids for manufacturing, single frequency fluid characterisation cannot reliably predict good jetting behaviour, owing to the range of shearing and extensional flow rates involved. However, the scope of inkjet fluid assessments (beyond achievement of a nominal viscosity within the print head design specification) is usually focused on the final application rather than the jetting processes. The experimental demonstration of the clear insufficiency of such approaches shows that fluid jetting can readily discriminate between fluids assessed as having similar LVE characterisation (within a factor of 2) for typical commercial rheometer measurements at shearing rates reaching 104 rad s−1.

Jetting behaviour of weakly elastic dilute linear polystyrene solutions, for molecular weights of 110–488 kDa, recorded using high speed video was compared with recent results from numerical modelling and capillary thinning studies of the same solutions.

The jetting images show behaviour ranging from near-Newtonian to “beads-on-a-string”. The inkjet printing behaviour does not correlate simply with the measured extensional relaxation times or Zimm times, but may be consistent with non-linear extensibility L and the production of fully extended polymer molecules in the thinning jet ligament.

Fluid test methods allowing a more complete characterisation of NLVE parameters are needed to assess inkjet printing feasibility prior to directly jetting complex fluids. At the present time, directly jetting such fluids may prove to be the only alternative.

Keywords:Inkjet, Polymer solutions, Viscosity, Elasticity, Finite-extensibility, Beads-on-string
Subjects:H Engineering > H141 Fluid Mechanics
F Physical Sciences > F200 Materials Science
H Engineering > H990 Engineering not elsewhere classified
Divisions:College of Science > School of Mathematics and Physics
ID Code:36880
Deposited On:05 Sep 2019 10:42

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