Printing Functional Materials

Jennifer A. Lewis and Scott C. Slimmer

Harvard School of Engineering and Applied Sciences

Wyss Institute for Biologically Inspired Engineering

jalewis@seas.harvard.edu

“…significant improvements to multi-material

technology is the breakthrough that is required.”

Jeffries Report 2013

“Integrating electronics into a part and printing

both simultaneously could forever change the

way some products are designed and

manufactured.

Wohlers Report 2013

New materials are needed to enable functional parts

Form

Function

Broaden materials palette for 3D printing

Co-print multiple materials

Integrate form and function

Improve feature resolution by 100x

Improve throughput by 100x

Our overarching focus

… expedite transformation from rapid prototyping

to manufacturing of advanced materials

Key Criteria:

• ink must flow through nozzle without jamming

• ink must solidify rapidly

• concentrated inks minimize shrinkage during drying

decreasing feature size 250 m 250 nm

ceramic inks sol-gel inks polymer inks wax inks

conductive inks

Functional inks for 3D printing

10x10x5 cm3 ± 50 nm 1m2x10 cm ± 5 m

V = 0.1 -10 mm/s V = 1 -1000 mm/s

Moderate Area

High Precision Printer

Large Area

High Speed Printer

Custom-designed 3D printers

Large-Area, Multimaterial 3D Printer

Printer design:

- built by Aerotech to our specs

Key Attributes:

- Filamentary ink deposition

- Four ink heads

four dyed PDMS inks

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials, (2014)

Large-Area, Multimaterial 3D Printer

20 nm average , 5 – 50 nm distribution

Ahn, Duoss, Nuzzo, Rogers, Lewis, et al., Science (2009); Ahn, Duoss, and Lewis, US-Patent 7,922,939

Silver inks for 3D printed electronics

Ahn, Duoss, Nuzzo, Rogers, Lewis, et al., Science (2009); Ahn, Duoss, and Lewis, US-Patent 7,922,939

Russo et al., Advanced Materials (2011)

Silver inks are highly conductive as-printed

Silver inks for 3D printed electronics

1 m nozzle 5 m nozzle 10 m nozzle

30 m nozzle 5 m nozzle

10 m nozzle

5 m nozzle 10 m nozzle 30 m nozzle

Ahn, Duoss, Nuzzo, Rogers, Lewis et al. Science (2009). Ahn, Duoss, and Lewis, US-Patent 7,922,939

Silver inks for 3D printed electronics

8-arm antenna

silver Electrodes (100 m)

glass Support

25.8 mm diameter

Adams, Duoss, Malkowski, Ahn, Nuzzo, Bernhard, Lewis, Advanced Materials (2011)

conductive epoxy copper-backed substrate

feed point ka = 0.41

with Bernhard group (ECE @ Illinois)

0

2

k

ka < 0.5 indicates an electrically small antenna (ESA)

Conformal printing of electrically small antennas

BW ~ 14.3%

Resonant at ~1.7 GHz

Efficiency ~71%

Concave antenna

Adams, Duoss, Malkowski, Ahn, Nuzzo, Bernhard, Lewis, Advanced Materials (2011)

VSWR: a measure of signal reflected at component junctions

Ideally, VSWR = 1 (no reflected power, no mismatch loss)

Performance characteristics

Embedded 3D printing of stretchable sensors

Carbon-based conductive ink is printed within a

highly elastic matrix

> 400% strain is possible

Stretchable sensors for biomedical, soft robotics, and athletics

Stretchable sensors for biomedical, soft robotics, and athletics

Highly stretchable, multilayer pressure + strain sensors

For autonomous devices that:

1) Harvest energy

2) Store and deliver energy

3) Perform function

X

Warneke et al., Computer 2001

Lai et al., Adv. Mater. 2010

Our goal:

Print 3D microbatteries (>1 mm3)

i.e., size of a single grain of sand (!) battery

device

3D printing of Li ion microbatteries

LTO

LFP

c)

Current collector (Au)

Glass

a) Nozzle (30 m)

b)

LTO

Packaging d)

LFP ink (cathode)

LTO ink (anode)

K. Sun,T.-S. Wei, B.Y. Ahn, Lewis, Dillon et al, Adv. Mater. (2013)

3D printing of Li ion microbatteries

Sand grains

1 mm

each microbattery equivalent in size to a single grain of sand

Battery ink printing

3D printing of Li ion microbatteries

Printed and packaged 3D microbattery

200 m

Li ion microbatteries exhibit excellent energy and power densities

K. Sun,T.-S. Wei, B.Y. Ahn, Lewis, Dillon et al, Adv. Mater. (2013)

Ref 34: Chiang (MIT)

3D-IMA (Lewis, Dillon)

Ref 37: Braun, King (UIUC)

areal densities | 1st gen printed batteries exhibit exceptional performance!

Microbattery Performance

Scalable Li Ion Microbatteries

New scalable process to create custom batteries for

pick-and-place 3D printing

“…significant improvements to

multi-material technology is the

breakthrough that is required.”

Jeffries Report 2013

New materials are needed to enable living tissue printing

Form

Function

Hydroxyapatite Scaffolds

Michna, Wu, Lewis, Biomaterials (2005); Simon et al, JBMR (2007)

Hard scaffolds for tissue engineering

3D rendering of

micro-CT scan

3D model

of implant Printed

scaffold

Lewis, Smay, Stuecker, Cesarano, J. Am. Ceram. Soc. (2006)

0.8mm (cancellous bone)

0.4mm (compact bone) 1mm

Silk-Hydroxyapatite Scaffolds

After immersion, still wet condition

Sun, Lewis, Kaplan, et al. Adv. Healthcare Mat. (2012)

Hydrogel Scaffolds

20 m

Shepherd, et al., Adv. Mater. (2011).

Polyelectrolyte Scaffolds

G. Gratson, M. Xu, J.A. Lewis, Nature (2004).

10 m

20 m

Ghosh et al. Adv. Funct. Mater. (2008).

Silk Fibroin Scaffolds

Soft scaffolds for tissue engineering

3D bioprinting of living tissue constructs

unit cell

Cell-laden

Ink(s) Fugitive ink

(vasculature)

Hydrogel ink

(ECM)

Targeted applications: drug screening, tissue engineering, and organ repair

Fugitive and cell-laden inks

Inks exhibit complimentary fluid-to-gel transitions

GFP fibroblasts in printed filaments

4x

3D printing of cell-laden inks: Cell viability

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials (2014)

Printing 1D, 2D, 3D vascular networks 1-D

2-D

3-D

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials (2014)

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials (2014)

3D bioprinting of vascularized tissue constructs

Interpenetrating network of

cell-laden filaments and

vascular channels

500 µm

GFP HNDFs RFP HUVECs 10T1/2

MFs Top view

Side view

Simple 4-layer construct to aid visualization

Co-printing fugitive and cell-laden inks

3D bioprinting of vascularized tissue constructs

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials (2014)

Vascularized living tissue constructs

500 µm

GFP HNDFs

RFP HUVECs

10T1/2 MFs

DB Kolesky, R Truby, S Gladman, T Busbee, K Homan, and JA Lewis, Advanced Materials (2014)

3D printed light-weight lattices

Compton and Lewis (unpublished)

Large-area (1 m2) 3D structures printed in minutes using multinozzle printheads

High throughput printing of 3D architectures Periodic polymer

foam

8-n

ozzle array

Dual multinozzle printhead

3D Interpenetrating

Architectures

Large-area (1 m2) 3D structures printed in minutes using multinozzle printheads

Periodic polymer

foam

8-n

ozzle array

High throughput printing of 3D architectures

3D Printing: Integrating form + function