1

Richard W. Siegel

14 October 2003

Assembling Assembling NanomaterialsNanomaterials

Rensselaer Nanotechnology Center Rensselaer Nanotechnology Center Rensselaer Polytechnic InstituteRensselaer Polytechnic Institute

Korea-U.S. NanoForumSeoul, Korea

2

materials

physics biology chemistry

The Materials WorldThe Materials World

“Those who control materials control technology”Eiji Kobayashi, Panasonic

Rensselaer Nanotechnology CenterRensselaer Nanotechnology Center

AdministrationR.W. Siegel, Director

Nanostructures& Nanodevices

NanocompositeMaterials

Computational Modeling &

Design

Nanomaterials for Biotechnology

Management & SocioeconomicImplications

Founded April 2001Founded April 2001

3

U.S. Army

Natick Soldier CenterEastman Kodak

National Science Foundation

State of New York

Nanotechnology Sponsors at RensselaerNanotechnology Sponsors at Rensselaer

U.S. Department of Energy

Sources of Funding for the Rensselaer Nanotechnology Center

NSF33%

Other Federal35%

Industry16%

NY State8%

RPI8%

annual funding ca. $6 million

Sources of Funding in the Sources of Funding in the Rensselaer Nanotechnology CenterRensselaer Nanotechnology Center

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K-12 ProgramsUndergraduate Colleges

MorehouseMount Holyoke

SmithSpelmanWilliams

Distance-learningVisiting Researchers

Industry PartnersABB

Albany International

IBMEastman Kodak

Philip Morris

New York State

RensselaerPolytechnic Institute

University of Illinoisat Urbana-Champaign

Nanoscale Science and Engineering Centerfor Directed Assembly of Nanostructures

www.rpi.edu/dept/nsec

Founded September 2001Founded September 2001

Why Directed Assembly?Why Directed Assembly?

http://www.nano.gov/

dispersions dispersions and coatingsand coatings

high surface high surface area materialsarea materials

consolidated consolidated materialsmaterials

functional functional nanodevicesnanodevices

nanoscale building blocks

synthesisatoms

layersnanoparticles

nanostructured materials and devices

fundamental gateway to the eventual success

of nanotechnologyassembly

nanotubes

applications in our macroscopic world

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Ø Size confinement

Ø High surface area

Ø Many interfaces

What is special about What is special about nanoscale nanoscale building blocks?building blocks?

Ø Size confinement

Ø High surface area

Ø Many interfaces

What is special about What is special about nanoscale nanoscale building blocks?building blocks?

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NSEC research thrust 1 projectsNanoparticle Synthesis(Benicewicz , Braun, Moore, Siegel)

- organic and inorganic particles- chemically heterogeneous surfaces

Phase Behavior of Nanoparticle-Polymer Mixtures(Schweizer, Zukoski)

- study scattering and rheological properties- provide comparison to modeling efforts- provide understanding for novel assembly

Polymer Nanocomposites(Lookman, Schadler, Siegel)

- explore effects of novel nanoparticle fillers(isolated particles, strings, clusters)

- tailor interface between filler and polymer matrix- assemble multifunctional nanocomposites

Directed Assembly of Nanostructured Materials(Lewis, Schadler, Zukoski)

- design concentratednanoparticle gels for direct-writing- fabricate polymernanocomposites with hierarchical

features

10 nm

1 mm

3-D lattice 1mm

NanoparticleNanoparticle--assembled TiOassembled TiO22 microtubesmicrotubes

1 µm 100 nm

Ma, Siegel, Schadler (2003)

6 µm 350 nm

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Nanotube pillars

SiO2 islandsSid

Wei, Vajtai, Jung, Ward, Zhang, Ramanath, Ajayan (2002)

Controlled assembly of Controlled assembly of nanotube nanotube arraysarrays

50 µm

Vertical and Horizontal

Funded by ONR and the MARCO Interconnect Focus Center (Collaboration with Motorola)

Carbon nanotube interconnects

2 µm

Ajayan, Wei, et al. (2003)

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Creating singleCreating single--wall nanotube junctionswall nanotube junctions

e-beam welding

FutureTerrones, Banhart, Ajayan et al. (2002)

Funded by the MARCO Interconnect Focus Center

Cathode

Glass

insulator

MWNT Film Anode

A C

B

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

V

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

V

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

Si Substrate

Al plate

I

Glass Insulator MWNTs (30 micron)

V

Carbon nanotube gas breakdown sensor

Koratkar, Ajayan et al., Nature (10 July 2003)

200 400 600 800 1000 12000

5 0

100

150

200

250

300

350

400

450

500

Potential difference across electrodes (volts)

Cur

rent

dis

char

ge (

mic

ro-a

mpe

res)

Al: Cathode

Al: Anode

150 µm

Si0 2

Al: Cathode

MWNT Film(Anode)

150 µm

200 400 600 800 1000 12000

5 0

100

150

200

250

300

350

400

450

500

Potential difference across electrodes (volts)

Cur

rent

dis

char

ge (

mic

ro-a

mpe

res)

Al: Cathode

Al: Anode

150 µm

Si0 2

Al: Cathode

MWNT Film(Anode)

150 µm

200 400 600 800 1000 12000

5 0

100

150

200

250

300

350

400

450

500

Potential difference across electrodes (volts)

Cur

rent

dis

char

ge (

mic

ro-a

mpe

res)

Al: Cathode

Al: Anode

150 µm

Al: Cathode

Al: Anode

150 µm

Si0 2

Al: Cathode

MWNT Film(Anode)

150 µm

Si0 2

Al: Cathode

MWNT Film(Anode)

150 µm

100 150 200 250 300 350 400 4500

100

200

300

400

500

600

Dis

char

ge C

urre

nt (m

icro

-am

pere

s)

Breakdown Volatge (Volts)

He

Ar Air

CO2

N2

O2 NH3

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Attachment of Au Attachment of Au nanoparticles nanoparticles to Nto N--doped doped CNTsCNTs

50 nm

H2SO4/HNO

3

gold colloid

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

o

N+

n

Functional groups are attached along the lengths and ends of N-doped carbon nanotubes (CNT). These become the sites for selective Au nanoparticle attachment.

Jiang, Eitan, Schadler, Ajayan, Siegel, et al. (2003)

Funded by US Army Natick Soldier Center

Polymer Polymer nanocompositesnanocomposites

♦ Control Filler Properties− particle size− shape (spheres, nanotubes… ) − interface chemistry/functionality− connectivity

* isolated species* chains* aggregates

−filler volume fraction

Goal: Design compositeswith tailored properties- Mechanical - Optical - Electrical...

Rg > R > d < 1 nm~

d

2R

Issues:- Dispersion/miscibility- Interface mechanics- Polymer properties change

due to filler

10

0

10

20

30

40

50

60

70

80

0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4 0.45 0.5

Strain (mm/mm)

Str

ess

(MP

a)

NEAT PMMA

PMMA + 5wt% nano-alumina

PMMA + 5 wt% micron-size alumina

Comparison between micronComparison between micron--size and size and nanoscalenanoscale alumina fillers in PMMAalumina fillers in PMMA

Ash, Schadler, Siegel (2002)Ash, Schadler, Siegel (2002)

Mechanical behavior of filled and neat PMMA

c

0 1 2 3 4 5

20

25

30

35

40

Weight Percent of Refined Al2 O3 in 5wt% Deionized Gel Solution

Scr

atch

Wid

th, µ

m

100

200

300

400

500

Scratch D

epth, nm

40

35

30

25

20

0 10 20 30 40 50

500

400

300

200

100

Nano-alumina filled gelatin

50 wt% nano-alumina

16.7 wt% nano-alumina filled gelatin

Scra

tch

dept

h (µ

m)

Scra

tch

wid

th (µ

m)

Weight % alumina

Chen, Schadler, Siegel, Irvin (2002)

Polymer Polymer nanocomposites nanocomposites –– assembly and propertiesassembly and properties

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1 µ m

Hong, Schadler, Siegel, Mårtensson (2002)

SEM of 50 wt% ZnO in LDPE

LDPE / ZnO nanocomposite

Resistivity Resistivity of of ZnOZnO/LDPE /LDPE nanocompositesnanocomposites

Continuous paths

Tunneling

Conduction mechanisms:

Hong, Schadler, Siegel, Mårtensson (2002)

0 10 20 30 40 50108

1010

1012

1014

1016

1018

1020

1022 10 kV/cm

Res

isti

vity

(Ω톍

m)

ZnO Content (Vol. %)

PE / ZnO nanoparticles (49nm) PE / ZnO micron particles (300nm) PE / ZnO nanoparticles (24nm) PE powder / ZnO nanoparticles (49nm)

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Protein-NanoparticleComposites

(Dordick, Schadler, Ajayan)

NSEC research thrust 2 projects

Characterization(Ramanath, Ajayan)

Preparation/Synthesis (Ajayan, Crivello)

Molecular Modeling(Garde, Redondo)

Tissue Engineering/Biosensing(Bizios, Siegel, Dordick)

Biorecognition-DrivenSelf-Assembly

(Wong, Lu, Dordick, Siegel)

Potential applications of biocatalytic nanocompositesPotential applications of biocatalytic nanocomposites

Ø CatalystsØ Chromatographic packingsØ Biocatalytic membranesØ Non-fouling coatings and paints

• Protein, lipid, polysaccharide resistant• Microbial resistant• Sessile invertebrate resistant

Ø Non-clogging drain pipesØ Implantable medical devicesØMicroelectronics and microfabrication

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COOHH2SO4 : HNO3

3:1 NHS

EDACEnzymeNH2

Biofunctionalizing Biofunctionalizing carbon carbon nanotubesnanotubes

Peroxidase

200 nm

Rel

ativ

e ch

ymot

ryps

in a

ctiv

ity

0 . 0

0 .2

0 .4

0 .6

0 .8

1 .0

1 .2

Rel

ativ

e S

BP

act

ivity

0.0

0.2

0.4

0.6

0.8

1.0

1.2

C o n t r o l - C T

N - N T / C T1 4 %

S o l u t i o n - C T

C o n t r o l - S B P

N - N T / S B P1 8 %

S o l u t i o n - S B P

Very high intrinsic activity for unrelated enzymes.Indicates a stable and active biocatalyst nanoscale preparation

Cellular Cellular compatabilitycompatability

0

1000

2000

3000

4000

Osteoblasts Fibroblasts Endothelial Cells

Cel

l Den

sity

(ce

lls/

squ

are

cm)

Glass (reference substrate)

167 nm grain size alumina

45 nm grain size alumina

24 nm grain size alumina

*

*

**

*‡‡

Glass (reference substrate)

Webster, Siegel, Bizios (2001)

Data for alumina nanoceramic; similar behavior found for other nanoceramics and ceramic/polymer nanocomposites

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Osteoblast and fibroblast adhesionOsteoblast and fibroblast adhesionon conventional and on conventional and nanophase nanophase alumina / PLA alumina / PLA compositescomposites

0

1000

2000

3000

4000

0 30 40 50 100

*‡ *

*

0

1000

2000

3000

4000

0 30 40 50 100

** *

Cel

l Den

sity

(cel

ls/c

m2 )

Substrates (% alumina loading)

Values are mean ±SEM; n=3;

*p<0.05 (compared to osteoblast adhesion on the respective 100% alumina; Student’s t-test);

‡ p<0.05 (compared to fibroblast adhesion on 100% alumina; Student’s t-test).

Osteoblasts Fibroblasts

Conventional Alumina Nanophase Alumina

McManus, Siegel, Bizios (2001)

CaCaCa

Vitronectin

Ca

RGD

24 nm grain size

OSTEOBLAST

Ca

RGD

Conventional Alumina

167 nm grain size

OSTEOBLAST

Integrin receptors Integrin receptors

Osteoblast Osteoblast adhesionadhesion

Nanophase Alumina

driven by surface topography

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Conclusions:Conclusions:

ØWe are now able to create a wide variety of nanoscale building blocks

ØWe are learning how to assemble them into useful nanostructured materials

Ø Hierarchical systems at the micro-scale and beyond are beginning to be created

Ø Society is beginning to benefit from nanoscience and its applications

Ø There is much more to come… .!

Rensselaer Nanotechnology Center Rensselaer Polytechnic Institute

R. W. Siegel

100 µm

Thank you

Ajayan, Nugent, Siegel, Wei, Kohler-Redlich, Nature (2000)