title: Deposition of nano-hydroxyapatite particles utilising direct and transitional electrohydrodynamic processes.
abstract: Electrohydrodynamic spraying is a well established process used to deposit, coat, analyse and synthesise materials within the biomedical remit. Recently, electrohydrodynamic printing has been developed to afford structures for potential applications in the biomedical and medical engineering fields. Both of these processes rely on the formation of an electrically-induced jet, however the resulting products can be made strikingly different and offer potential in broader applications. Here we show how spraying and printing are linked by elucidating the ease of transition between the processes. Changes in the deposition distance can result in either spray (>10 mm) or print formation (<3 mm), with an overlap of the two in between this range. For the optimal printing distance of 0.5 mm, gradual changes in the applied voltage (0-4.5 kV) encounters transitional printing modes (dripping, micro-dripping, rapid micro-dripping, unstable and stable jetting) which can be utilised for patterning. The results indicate the robustness of the electrohydrodynamic route in the nano-materials processing arena, with emphasis on biomedical materials.
authors.affiliation: Department of Mechanical Engineering, University College London, Torrington Place, London WC1E 7JE, UK. zeeshan.ahmad@ucl.ac.uk
authors.forename: Z
authors.initials: Z
authors.lastname: Ahmad
authors.forename: E S
authors.initials: ES
authors.lastname: Thian
authors.forename: J
authors.initials: J
authors.lastname: Huang
authors.forename: M J
authors.initials: MJ
authors.lastname: Edirisinghe
authors.forename: S M
authors.initials: SM
authors.lastname: Best
authors.forename: S N
authors.initials: SN
authors.lastname: Jayasinghe
authors.forename: W
authors.initials: W
authors.lastname: Bonfield
authors.forename: R A
authors.initials: RA
authors.lastname: Brooks
authors.forename: N
authors.initials: N
authors.lastname: Rushton
mesh_terms: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D004563:Electrochemistry / Q000379:methods; D000431:Ethanol / Q000737:chemistry; D005898:Glass; D008422:Materials Testing; D008670:Metals / Q000737:chemistry; D018613:Microscopy, Confocal; D046529:Microscopy, Electron, Transmission / Q000379:methods; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000379:methods*; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D018786:Bone Substitutes; D020099:Coated Materials, Biocompatible; D008670:Metals; D000431:Ethanol; D017886:Durapatite; D014025:Titanium