Reactive Inkjet Printing Patrick J. Smith University of Sheffield 15 th November 2017
Sheffield Applied Inkjet Research Lab Here we are! Main Research themes Tissue engineering Reactive Inkjet Printing Printed Electronics Inkjet & Composites
Overview Exploiting inkjet s advantage reactive inkjet printing Printing silk structures
Playing to strengths Inkjet Printing can add a variety of materials to the same layer A 100 office printer handles four types of ink! 124 November, 2017 Patrick.Smith@sheffield.ac.uk
Goodbye Mr. Ford Any customer can have a car painted any colour that he wants so long as it is black. Instead of: Why not: 12 November, 2017 Patrick.Smith@sheffield.ac.uk 5
Reactive Inkjet Printing Traditional Route R.I.J. Make Nanoparticles Stabilise Nanoparticles Make/Store Ink Make Nanoparticles Make Device Make Device A silver MOD ink generates NPs in-situ, giving 50 75 % bulk silver conductivity A normal nanoparticle ink gives conductivities of 10-40 % Macromol. Rapid Commun., 2005, 26, 315 Can we use the same energy for synthesis that we use for patterning? 12 November, 2017 Patrick.Smith@sheffield.ac.uk 6
Reactive Inkjet Printing Spin-coat first layer then print second reagent Inkjet first layer then print second reagent Side view Of course, one can inkjet print more precise patterns Plan view 12 November, 2017 Patrick.Smith@sheffield.ac.uk 7
A Great RIJ Example RIJ = reactive inkjet printing Schematic of selective emitter solar cell structure fabricated using the direct patterned etching method. Direct patterned etching of silicon dioxide uses inkjet to deposit an inactive etching component onto a water soluble surface layer formed over the silicon dioxide. The inactive component reacts with the surface layer, where it contacts, to form an active etchant which etches the silicon dioxide under the surface layer to form a pattern of openings. The method involves fewer steps, lower chemical usage and generates less hazardous chemical waste. A. Lennon et al. Solar Energy Materials & Solar Cells 93 (2009) 1865 1874 8
What can we do with an inkjet printer? We can tailor droplet size We can position the droplet anywhere we like on the substrate We can print up to four inks Either side by side or on top of each other We can control the evaporation rate By using solvent ratios, and varying inter-droplet drying time 12 November, 2017 Patrick.Smith@sheffield.ac.uk 9
Inkjet printer in Sheffield (MicroFab 4, piezoelectric DOD) Camera Printhead holder Printhead Droplet
Magnetite films by reactive printing
Reactants Inks used Iron (II) Chloride and Iron (III) Chloride in water (Ink 1) Sodium hydroxide in water (Ink 2) All reactants loaded in inks to correct stoichiometry FeCl 2 + 2FeCl 3 +8NaOH -> Fe 3 O 4 +8NaCl
Magnetite thick film Definitely magnetic!
14 Silk
Regenerated Silk Fibroin as a Bio-ink for printing A promising method for bio scaffold fabrication. 100 μs 200 μs 300 μs Advantages of Regenerated Silk Fibroin: An FDA approved biomaterial Good biocompatibility, biodegradability, mechanical properties Natural peptides in aqueous solution Insoluble after menthol fixing Better printability than collagen, gelatin, alginate
Schematic of Janus silk rocket printing process Gregory et al. Small 2016, 12, 4048-4055.
Diameter & Height f Optical profiler microscope images of silk dots printed using different concentrations of RSF inks: (a) 10, (b) 20, (c) 30, and (d) 40 mg/ml, respectively. (e) The diameter of the dots plotted against the concentrations of RSF solutions. (f) Height plotted against printed layers.
Printing different patterns c d e Images of various printed patterns. a) Lines are produced by adjusting the distance of two adjacent droplets. (b) SHEFFIELD ENGINEERING logo. (c) A silk worm picture printed on filter paper. (d) Dot arrays. (e) Printed pillars.
Characterization of silk particles red arrow PMMA barrier layer Fully active rocket Janus Rocket
Effect of blending PEG 400 into Silk/Cat Fully active silk particle without PEG 400 Fully active silk particle with PEG 400
Swimming in H 2 O 2 fuel Fully Active Particle Janus Particle 500µm 500µm Type of Particle Average velocity [µm/s] Persistence length [µm] Fully Active 370 ± 30 26 ± 6 Janus (half active) 510 ± 90 420 ± 180
Directionality of motion controlled via printing Fully active particle (correlation coefficient=0.003) Fully active particle Janus particle (correlation coefficient=0.66) Janus particle
Comparison Fully active and Janus Rockets in 2% Serum Solution with 3% H 2 O 2 Fully Active Rocket In 2% Serum with 3% H 2 O 2 Janus Rocket In 2% Serum with 3% H 2 O 2
Comparison of Fully active and Janus Rockets swimming in 2% Human Serum with 3% H 2 O 2 fuel Fully Active Rocket In 2% Serum with 3% H 2 O 2 Janus Rocket In 2% Serum with 3% H 2 O 2 600µm
Impact & Media attention News: https://www.sciencedaily.com; http://sciencenewsjournal.com; http://phys.org; http://healthmedicinet.com; http://www.eurekalert.org; http://www.popsci.com; http://www.medgadget.com; http://www.americanlaboratory.com; http://www.in-pharmatechnologist.com; http://www.3ders.org; https://3dprint.com; http://www.gereports.com; http://www.hospimedica.com; http://3dprintingfromscratch.com; http://nextbigfuture.com Journal Inside Front Cover Gregory et al. Reactive inkjet printing of biocompatible enzyme powered silk micro-rockets. Small 2016, 12, 4048-4055.
Single engine spinner Schematic of silk spinner printing Dual engine spinner
SEM images of the printed spinners A B C D E F
Single & dual engine spinners 0 S 1 S 5 S 10 S 15 S 20 S 0 S 1 S 5 S 10 S 15 S 20 S
Type Of Swimmers Average Velocity (µm/s) Velocity A / B (µm/s) Rotation Speed (rpm) Single 680 ± 240 1300 ± 400 / 550 ± 130 6.6 Dual 680 ± 180 970 ± 270 / 1020 ± 220 6
H2O2 Concentration- 100 mg/ml 0 S 1 S 5 S 10 S 15 S 20 S
Velocity and Rotation Speed data for the silk spinners in different concentrations of H2O2 A B H 2 O 2 Concentration mg/ml Average Velocity (µm/s) Velocity A / B (µm/s) Rotation Speed (rpm) 1 100 ± 6 90 ± 8 / 80 ± 15 0 10 180 ± 20 210 ± 13 / 170 ± 140 0 20 430 ± 90 300 ± 180 / 270 ± 110 3.6 30 720 ± 210 800 ± 300 / 900 ± 400 4.5 60 1500 ± 400 2500 ± 800 / 2500 ± 500 6 100 2040 ± 290 3200 ± 400 / 3600 ± 500 12
Printed layers - 100 0 S 1 S 5 S 10 S 15 S 20 S
Velocity and Rotation Speed data for silk spinners with different layers Printed layers Average Velocity (µm/s) Velocity A / B (µm/s) Rotation Speed (rpm) 50 710 ± 180 1000 ± 400 / 1230 ± 260 4.5 100 1500 ± 500 2000 ± 600 / 2100 ± 700 18 150 2000 ± 700 2900 ± 800 / 3200 ± 1000 24
Self powered stirrer -100 layers 0 S 1 S 5 S 10 S 15 S 20 S
Velocity and Rotation Speed data for selfpowered silk spinners with different layers Printed Layers Average Velocity (µm/s) Velocity A / B (µm/s) 50 4000 ± 1000 7000 ± 4000 / 11000 ± 6000 100 6100 ± 2400 19000 ± 8000 / 20000 ± 8000 150 20000 ± 7000 30000 ± 10000 / 35000 ± 17000 Rotation Speed (rpm) 18 75 90
Silk spinners for micro-stirring 0 s 10 s 20 s 30 s Control 0 s 10 s 20 s 30 s With spinner 40 30 Control With spinner d / mm 20 10 0 0 10 20 30 40 50 60 70 Time / s
Summary Successfully printed silk inks with different patterns. Printed silk micro rockets that can swim in bio fluids and controlled their trajectory. Printed silk spinners with dual power systems and explored their application in micro stirring.
Acknowledgements I d like to thank Collaborators Dr Xiubo Zhao (CBE, Sheffield) Dr Steve Ebbens (CBE, Sheffield) PDRAs Dr David Gregory Dr Yi Zhang PhD students Miss Yu Zhang Funding bodies EPSRC University of Sheffield