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Reactive Inkjet Printing
Patrick J. SmithUniversity of Sheffield
15th November 2017
Sheffield Applied Inkjet Research Lab’
Here we are!
Main Research themes
Tissue engineeringReactive Inkjet Printing
Printed ElectronicsInkjet & 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!
12 November, 20174 [email protected]
Goodbye Mr. Ford
12 November, 2017 [email protected] 5
Any customer can have a car painted any colour that he wants so long as it is black.
Instead of:
Why not:
Reactive Inkjet Printing
12 November, 2017 [email protected] 6
Traditional Route R.I.J.
Make Nanoparticles
StabiliseNanoparticles
Make/Store Ink
Make Device
Make Nanoparticles
Make Device
Macromol. Rapid Commun., 2005, 26, 315
A silver MOD ink generates NPs in-situ, giving 50 – 75 % bulk silver conductivityA normal nanoparticle ink gives conductivities of 10 - 40 %
Can we use the same energy for synthesis that we use for patterning?
Reactive Inkjet Printing
12 November, 2017 [email protected] 7
Spin-coat first layer then print second reagent
Inkjet first layer then print second reagent
Of course, one can inkjet print more precise patterns
Side viewPlan view
A Great RIJ Example
8
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 ofopenings. 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
RIJ = reactive inkjet printing
What can we do with an inkjet printer?
12 November, 2017 [email protected] 9
• 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
Inkjet printer in Sheffield (MicroFab 4, piezoelectric DOD)
Camera
Printheadholder
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
FeCl2 + 2FeCl3 +8NaOH -> Fe3O4 +8NaCl
Magnetite thick film
Definitely magnetic!
Silk
14
A promising method for bio scaffold fabrication.
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
Regenerated Silk Fibroin as a Bio-ink for printing
100 μs 200 μs 300 μs
Schematic of Janus silk rocket printing process
Gregory et al. Small 2016, 12, 4048-4055.
Diameter & Height
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.
f
Printing different patterns
Images of various printed patterns. a) Lines are produced by adjusting the distance of twoadjacent droplets. (b) ‘SHEFFIELD ENGINEERING’ logo. (c) A silk worm picture printed on filterpaper. (d) Dot arrays. (e) Printed pillars.
ed
c
Characterization of silk particles
red arrow PMMA barrier layer
Fully active rocket Janus Rocket
Effect of blending PEG400 into Silk/Cat
Fully active silk particle without PEG400 Fully active silk particle with PEG400
Swimming in H2O2 fuel
Fully Active Particle Janus Particle
Type of ParticleAverage velocity
[µm/s]
Persistence length
[µm]
Fully Active 370 ± 30 26 ± 6
Janus (half active) 510 ± 90 420 ± 180
500µm 500µm
Directionality of motion controlled via printing
Fully active particle (correlation coefficient=0.003) Janus particle (correlation coefficient=0.66)
Fully active particle Janus particle
Comparison Fully active and Janus Rockets in 2% Serum Solution with 3% H2O2
Janus Rocket In 2% Serum with 3% H2O2Fully Active Rocket In 2% Serum with 3% H2O2
Comparison of Fully active and Janus Rockets swimming in 2% Human Serum with 3% H2O2 fuel
Janus Rocket In 2% Serum with 3% H2O2Fully Active Rocket In 2% Serum with 3% H2O2
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
Gregory et al. Reactive inkjet printing of biocompatible enzyme powered silk micro-rockets. Small 2016, 12, 4048-4055.
Journal Inside Front Cover
Schematic of silk spinner printingSingle engine spinner
Dual engine spinner
SEM images of the printed spinners
A B C
D E F
Single & dual engine spinners
0 S 5 S
10 S 15 S
1 S
20 S
0 S 5 S
10 S 15 S
1 S
20 S
Type Of Swimmers
Average Velocity (µm/s)
VelocityA / B
(µm/s)
RotationSpeed(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 5 S
10 S 15 S
1 S
20 S
Velocity and Rotation Speed data for the silk spinners in different concentrations of H2O2
H2O2
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
AB
Printed layers - 100
0 S 5 S
10 S 15 S
1 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 5 S
10 S 15 S
1 S
20 S
Printed Layers
Average Velocity
(µm/s)
Velocity
A / B
(µm/s)
Rotation Speed
(rpm)
50 4000 ± 1000 7000 ± 4000 / 11000 ± 6000
18
100 6100 ± 2400 19000 ± 8000 / 20000 ± 8000
75
150 20000 ± 7000 30000 ± 10000 / 35000 ± 17000
90
Velocity and Rotation Speed data for self-powered silk spinners with different layers
30 s20 s10 s0 s
Control
With spinner
0 s 10 s 20 s 30 s
Silk spinners for micro-stirring
0 10 20 30 40 50 60 700
10
20
30
40
d
/ m
m
Time / s
Control
With spinner
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.
Summary
I’d like to thank
CollaboratorsDr Xiubo Zhao (CBE, Sheffield)
Dr Steve Ebbens (CBE, Sheffield)
PDRAsDr David Gregory
Dr Yi Zhang
Acknowledgements
PhD studentsMiss Yu Zhang
Funding bodiesEPSRC
University of Sheffield
