The Supramolecular Nano‐Materials Group

From Nano-Particles to Nano-Polymers

Francesco StellacciDepartment of Materials Science

and Engineering, MITfrstella@mit.edu

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The Supramolecular NanoMaterials Group

Supramolecular Materials Science

Monolayer Protected Metal Nanoparticles

FunctionalizedCarbon Nanotubes

Nanowires

Supramolecular Lithography Supramolecular

Nano Stamping

Jackson, Myerson, Stellacci, Nat. Mat., 3, 330, 2004Akthakul, Stellacci, Mayes,. Adv. Mat., 17, 532, 2005Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006DeVries, Brunnbauer, Stellacci, Science 315, 358, 2007Centrone, Yu, Stellacci,Small, 3, 814, 2007

Barsotti, O’Connell, Stellacci, Langmuir, 20, 4795, 2004Barsotti, Stellacci, J. Mat. Chem., 16, 962, 2006

Halik, M. et al. Nature, 431, 963, 2004

Yu, Stellacci, Nano Letters, 5, 1061, 2005Yu, Stellacci, JACS, 127, 16774, 2005 Yu, Stellacci, J. Mat. Chem., 16, 2868, 2006

Wunsch, Stellacci, Prato, manuscript in prepLong, Wu, Wunsch, Marzari, Stellacci in prep..Liu, Yuan, Kong, Stellacci manuscript in prep.

NANO-MATERIALS

LITHOGRAPHY

20 μm

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Metal Nanoparticles Synthesis

Metal Salt (AuHCl4) + HS

Reducing Agent (NaBH4)+HS

Ligand exchange reaction*

Direct mixed ligands reaction**

A. C. Templeton, M. P. Wuelfing and R. W. Murray, Accounts Chem. Res. 2000, 33, 27F. Stellacci, et al. Adv. Mat. 2002, 14, 194

HS

HS

HS

HS

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Nanoparticle Absorption

12 2

1 2( 2 )m

εσε ε ε

=+ +

Mie theory describes the absorption, σ, of small metallic particles:

mεgoldε

εm is a volume-average of the dielectric constants (ε) of the ligand molecules and the solvent

4-Aminophenyldisulfide(APS)

Electron donor

4-Fluorobenzenethiol(FBT)

Electron acceptor

5,5’-Dithiobis(2-nitrobenzoic acid)(NBA)

Electron acceptor

Dimethyl (4,4’ dithiobiscinnamate)(CIN)

Electron acceptor

F

SH SH

NO2

OH

O

SH

OO

NH2

SH

Conjugated molecules:

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Absorption by Functionalized Nanoparticles

• Trend in ε predicted by polarizability of molecules • Steric hindrance of NBA molecule causes porous ligand shell,

effectively lowering ε relative to expected value

By Mie theory:

CIN

FBT

APS

(NBA)

Increasing ε

522

530

510

541

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

300 400 500 600 700 800Wavelength (nm)

Abs

orpt

ion

AminophenyldisulfideFluorobenzenethiolNitrobenzoic acidCinnamate

Spectra taken in dichlorobenzene (DCB) F

SH

SH

NO2

OH

O

SH

OO

NH2

SH

Absorption spectra for fully conjugated nanoparticles

*

*

* Chromophore absorption from ligands; unrelated to plasmon resonance

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Increasingly Conjugated Nanoparticles

518

518

522

522

528

0.1

0.2

0.3

0.4

0.5

0.6

250 350 450 550 650 750 850Wavelength (nm)

Abs

orpt

ion

hexanethiol1:21:12:1conjugated

Absorption spectra for increasingly conjugated FBT series nanoparticles

Nanoparticles with varying ratios of:

SH

F

SH

HT

FBT

(low ε)

and

(high ε)

Larger fractions of conjugated FBT make ligand shell more polarizable; ε demonstrates corresponding increase

Similar trends are observed in other molecule series as well

More FBTIncreasing ε

HT HT FBT FBTeff

ligands

V VV

ε εε +=

Spectra taken in dichlorobenzene (DCB)

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Characterizing Metal Nanoparticles

2.7 nm

3 nm

TEM shows atoms in the core STM shows ligands in the shell

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Diameter =7.422nmLigand length= 1.08 nm

1.9nm

Average S-S spacing <x>=0.409 nm

Octanethiol (C8) homoligand np

Average STM observed headgroup spacing <S> = 0.5

Diameter=7.418Ligand length=1.56 nmAverage STM observed headgroup spacing <S>= 0.6305

Average S-S spacing<x>=0.3646 nm

Dodecanethiol (C12) homoligand np

Based on Luedtke and Landman Faraday Discussions 2004, 125, 1-22

S = STM observed spacingx = ligand spacing at core surface (adjacent Sulfur-Sulfur distance)D = STM observed np dimater (core + ligand shell)d = diameter of np core

Sd/2

D/2

x

S/D = x/d

Assumptions:The nanoparticle can be approximated as a sphereLigand length (L) is constant around the shell i.e. (D/2) = Constant

For a fully extended ligand chain of length L, with n carbon atoms, Use L = 0.12 (n+1) nm

W. D. Luedtke and Uzi LandmanJ. Phys. Chem. B, 102 (34), 6566,, 1998

Homoligand particle’s ligand structure

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Au (111)

STM Height Image of OT/MPA Mixed Monolayer on Au(111)

5 nm

Randomly distributed domains of OT form in a surrounding matrix of MPA

MPA

OT

R. Smith, S. Reed, P. Lewis, J. Monnell, R. Clegg, K. Kelly, L. Bumm, J. Huthison, P. Weiss. J. Phys. Chem. B 2001, 105, 1119-1122.

SHCOOH SH

Mixed SelfMixed Self--Assembled Assembled MonolayersMonolayers

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2 nm

a b

5 nm

c

2 nm

a b

5 nm

c

SH

MPA

OT

SHCOOH

STM Images of ‘Rippled’ Nanoparticles

b

5 nm

2 nm2 nm

ab c

c d

Jackson, Myerson, Stellacci, Nat. Mat., 3, 330, 2004Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006

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Hydrophobic/Hydrophilic Ripples

a

5 nm

a

5 nm

5 nm

2 nm2 nm

ab c

c d

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STM height image of OT:MPA 2:1 gold nanoparticles on gold foil

5 nmAu foil

hemispheresImaging Speed (µm/s)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Ave

rage

Spa

cing

(nm

)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Ave

rage

Spa

cing

(nm

)

Imaging Speed (µm/s)

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Ave

rage

Spa

cing

(nm

)

Imaging Speed (µm/s)

STM imaging of Nanoparticles

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

2

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1 1.1 1.2

Ave

rage

Spa

cing

(nm

)A

vera

ge S

paci

ng (n

m)

Imaging Speed (µm/s)

OT:MPA 2:1

OT:MPA 1:1

OT:MPA 30:1

Noise

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Noise and Ripples

ajs6_11_12

0.4

0.5

0.6

0.7

0.8

0.9

1

4 4.5 5 5.5 6 6.5 7 7.5 8 8.5 9 9.5 10

Diameter [nm]

Rip

ple

Spac

ing

[nm

] .007.007'.007''.005.005'.005''

0.5 1.0 1.5 2.0 2.50.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

rippl

e sp

acin

g [n

m]

speed [um/s]0.5 1.0 1.5 2.0 2.5

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

rippl

e sp

acin

g [n

m]

speed [um/s]0.5 1.0 1.5 2.0 2.5

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

1.8

nois

e sp

acin

g [n

m]

speed [um/s]

b c

5 nm5 nm1.496 μm/s 5 nm5 nm1.496 μm/s 5 nm5 nm1.841 μm/s 5 nm5 nm1.841 μm/s5 nm5 nm1.595μm/s 5 nm5 nm1.595μm/s

a005 image taken at0.57 μm/s

Shows average ripple spacing of 0.699 nm ±0.098 nm

007 image taken at0.814 μm/s

Shows average ripple spacing of 0.743 nm ±0.052 nm

Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006

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Phase Separation on NanoparticlesPhase Separation on Nanoparticles

OT:MPA

OT:MUA

SH NH2SH NH2

Hexanethiol: p-Aminothiophenol

SH OH

O

SH

SH

Ag/-SH or /-NH2, Fe3O4 /-COOH, CaCO3/COOH

SH

OT:Mercaptohexanol

SHOH

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Increasing Curvature

Flat Au (111) on Mica

OT:MPA Mixed Monolayers formed on surfaces of varying curvatures

Au on Si, with 20 nm hemispheres

Au film with Au crystals ~ 10 nm

Au film with Au crystals ~ 4 nm

10 nm 10 nm 5 nm 5 nm

Curvature EffectsCurvature Effects

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The Hairy Ball Theorem and SAMs

Molecules in SAMs form a 2D crystal, that is a vectorial order.

Self-Assembled Monolayers The hairy ball theorem

The hairy ball theorem states that a vectorial order cannot propagate on a topological sphere unless the vector assumes a zero value in at least two points, called poles.

One Vector Two Vectors

*Poincarre, J. Math. Pure Appl. 1, 167, 1885; Nelson, Nano Lett., 2, 1125, 2002; DeVries, Science 315, 358, 2007; see also Zerbetto et al. Small, 2007

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• Molecules in SAMs form a specific angle with the surface normal in order to maximize van derWaals interactions.

• One can define a vector (from the attachment point to the projection of the molecular head group) to describe the molecular position.

What is the VectorialOrder in SAMs?

What is a topological sphere?

Thermodynamic interpretation

dodecane solution

W. D. Luedtke and Uzi Landman J. Phys. Chem. B, 102 (34), 6566,, 1998

solution

HS

HS HS

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Chemistry of chain formation

SH

OH

OSH

OH

O

SHHOOC

1. Pole functionalization with 11-Mercaptoundecanoic acid (MUA)

Short reaction times allow functionalization only at the polar singularities

2. Two-phase reaction: interface-controlled stoichiometry

NH2

NH2

1,6-Diaminohexanein water phase

Nanoparticles in toluene phase

“Nano-nylon”

Amide bonds

Precipitation at the toluene-water interface indicates the formation of insoluble material

Initial

PrecipitateFinal

SH SH

DeVries, Stellacci, Science 315, 358, 2007

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Nano-Nylon Two-Phase TEM images

100 nm

Nanoparticles

Chains

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Inter-Particle Distance

NH

O

NH

O

SHSH 5 5

NH

OO

O NH

O

SHSH 595

DAH theoretical length = 3.6 nm

EGDA theoretical length = 9.6 nm

Potential EGDA linker conformation

Measured interparticle

distance

Potential linker position

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Chains of Big Particles

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AcknowledgementsGraduate StudentsRobert J. Barsotti, Jr. (now at

Arkema. Senior Scientist)Gretchen A. DeVriesAlicia M. JacksonA. Amy Yu (also at MGH, post doc)Tan Mau WuBenjamin WunschOsman Bakr (Harvard)Suelin ChenJeffrey KunaSarah ThevenetOzge AkbulutJin Young KimHyewon KimJin-Mi Jung (KAIST)Ramona DallaPiccola (Trento)

Post-DocsMarkus Brunnbauer (now at

Infineon, Senior Scientist)Xiaogang “Bruno” Liu (now at NUS,

Assistant Professor)Brenda LongOktay UzunYing YuAndrea CentroneAyush VermaKazuya NakataCedric DuboisGeorg Heimel

NSF: NER DMI-0303821NIRT DMR-0086944NIRT SCP-0304019CAREER

NIH TPEN ProgramHewlett PackardDeshpande Center ACS-PRFReed Foundation at MIT CMSE-MRSEC DMR 02-13282Int. Copper AssociationMARCO3M Non Tenured Faculty Award3M Innovation AwardDuPont Young Professor AwardPackard Foundation AwardMineral Technologies

CollaboratorsDavid Nelson, HarvardLucia Pasquato, TriesteRalph Weissleder, Harvard, MGHMolly Stevens, Imperial C., UKHenry I. Smith, MITEnzo diFrabrizio, Catanzaro, ItalyAnthony Guiseppe-Elie, C. VirginiaMaurizio Prato, TriesteMarcus Halik, Erlangen U., GermanyAnne Mayes, MITSharon Glotzer, U. MichJoerg Lahan, U. Mich.Nicola Marzari, MITDarrell Irvine, MITKrystyn Van Vliet, MITRobert Cohen, MIT

UndergraduatesJacob M. Myerson ( now at MIT)Brian Netlner ( now at MIT)Angela TongNishi N. Rochelle (LSU, now at Purdue)Kathy Li (now at UT Austin)Peter Stone (now at Berkeley)Allon Houchbaum (now at Berkeley)Samantha Bennett (now at Cambridge UK)Tom Schilling (will join Berkeley)Paulo Silva (will join Northwestern)