From Nano-Particles to Nano-Polymers

Transcription

1 The Supramolecular Nano Materials Group From Nano-Particles to Nano-Polymers Francesco Stellacci Department of Materials Science and Engineering, MIT

2 The Supramolecular NanoMaterials Group Monolayer Protected Metal Nanoparticles Functionalized Carbon Nanotubes Nanowires Halik, M. et al. Nature, 431, 963, 2004 Jackson, Myerson, Stellacci, Nat. Mat., 3, 330, 2004 Akthakul, Stellacci, Mayes,. Adv. Mat., 17, 532, 2005 Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006 DeVries, Brunnbauer, Stellacci, Science 315, 358, 2007 Centrone, Yu, Stellacci,Small, 3, 814, 2007 Supramolecular Lithography NAN-MATERIALS Supramolecular Materials Science LITHGRAPHY 20 μm Wunsch, Stellacci, Prato, manuscript in prep Long, Wu, Wunsch, Marzari, Stellacci in prep.. Liu, Yuan, Kong, Stellacci manuscript in prep. Supramolecular Nano Stamping Barsotti, Connell, Stellacci, Langmuir, 20, 4795, 2004 Barsotti, Stellacci, J. Mat. Chem., 16, 962, 2006 Yu, Stellacci, Nano Letters, 5, 1061, 2005 Yu, Stellacci, JACS, 127, 16774, 2005 Yu, Stellacci, J. Mat. Chem., 16, 2868, 2006

3 Metal Nanoparticles Synthesis Metal Salt (AuHCl 4 ) + + Reducing Agent (NaBH 4 ) Direct mixed ligands reaction ** Ligand exchange reaction * F. Stellacci, et al. Adv. Mat. 2002, 14, 194 A. C. Templeton, M. P. Wuelfing and R. W. Murray, Accounts Chem. Res. 2000, 33, 27

4 σ = Nanoparticle Absorption Mie theory describes the absorption, σ, of small metallic particles: ε ( ε 2 ε ) ε m + 2 ε m is a volume-average of the dielectric constants (ε) of the ligand molecules and the solvent gold ε ε m Conjugated molecules: NH 2 F N 2 H 4-Aminophenyldisulfide (APS) 4-Fluorobenzenethiol (FBT) 5,5 -Dithiobis(2-nitrobenzoic acid) (NBA) Dimethyl (4,4 dithiobiscinnamate) (CIN) Electron donor Electron acceptor Electron acceptor Electron acceptor

5 Absorption by Functionalized Nanoparticles By Mie theory: CIN FBT APS (NBA) Absorption Spectra taken in dichlorobenzene (DCB) Absorption spectra for fully conjugated nanoparticles * N 2 * H F Aminophenyldisulfide Fluorobenzenethiol Nitrobenzoic acid Cinnamate NH 2 Increasing ε Wavelength (nm) Trend in ε predicted by polarizability of molecules Steric hindrance of NBA molecule causes porous ligand shell, effectively lowering ε relative to expected value * Chromophore absorption from ligands; unrelated to plasmon resonance

6 Increasingly Conjugated Nanoparticles Absorption Absorption spectra for increasingly conjugated FBT series nanoparticles Spectra taken in dichlorobenzene (DCB) More FBT Increasing ε hexanethiol 1:2 1:1 2:1 conjugated Nanoparticles with varying ratios of: (low ε) F HT and FBT ε eff V = ε + V V HT HT FBT FBT ligands ε Wavelength (nm) (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

7 Characterizing Metal Nanoparticles 3 nm TEM shows atoms in the core STM shows ligands in the shell 2.7 nm

8 Homoligand particle s ligand structure d/2 x D/2 S S = STM observed spacing x = ligand spacing at core surface (adjacent Sulfur-Sulfur distance) D = STM observed np dimater (core + ligand shell) d = diameter of np core S/D = x/d Assumptions: The nanoparticle can be approximated as a sphere Ligand 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 Based on Luedtke and Landman Faraday Discussions 2004, 125, 1-22 ctanethiol (C8) homoligand np W. D. Luedtke and Uzi Landman J. Phys. Chem. B, 102 (34), 6566,, 1998 Dodecanethiol (C12) homoligand np 1.9nm Average S-S spacing <x>=0.409 nm Diameter =7.422nm Ligand length= 1.08 nm Average STM observed headgroup spacing <S> = 0.5 Diameter=7.418 Average S-S spacing <x>= nm Ligand length=1.56 nm Average STM observed headgroup spacing <S>=

9 Mixed Self-Assembled Monolayers Au (111) MPA Randomly distributed domains of T form in a surrounding matrix of MPA CH 5 nm T STM Height Image of T/MPA Mixed Monolayer on Au(111) R. Smith, S. Reed, P. Lewis, J. Monnell, R. Clegg, K. Kelly, L. Bumm, J. Huthison, P. Weiss. J. Phys. Chem. B 2001, 105,

10 STM Images of Rippled Nanoparticles a b b c 5 nm 2 nm b a c MPA CH 2 nm c 2 nm d 5 nm T Jackson, Myerson, Stellacci, Nat. Mat., 3, 330, 2004 Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006

11 Hydrophobic/Hydrophilic Ripples a 5 nm b a c 2 nm c 2 nm d 5 nm

12 STM imaging of Nanoparticles Average Average Spacing (nm) Spacing (nm) (nm) (nm) T:MPA 2:1 T:MPA 1:1 T:MPA 30:1 Noise 5 nm STM height image of T:MPA 2:1 gold nanoparticles on gold foil Au foil hemispheres Imaging Speed (µm/s)

13 Noise and Ripples 005 image taken at 0.57 μm/s 007 image taken at μm/s a Shows average ripple spacing of nm ±0.098 nm Ripple Spacing [nm] Shows average ripple spacing of nm ± nm ajs6_11_ Diameter [nm] b noise spacing [nm] μm/s 5 nm 1.595μm/s 5 nm μm/s 5 nm speed [um/s] '.007'' '.005'' c ripple spacing [nm] speed [um/s] ripple spacing [nm] speed [um/s] Jackson, Silva, Hu, Stellacci, JACS., 128, 11135, 2006

14 Phase Separation on Nanoparticles H S NH 2 Hexanethiol: p-aminothiophenol Ag/- or /-NH 2, Fe 3 4 /-CH, CaC 3 /CH T:MPA H H T:Mercaptohexanol T:MUA

15 Curvature Effects T:MPA Mixed Monolayers formed on surfaces of varying curvatures Increasing Curvature 10 nm 10 nm 5 nm 5 nm Flat Au (111) on Mica Au on Si, with 20 nm hemispheres Au film with Au crystals ~ 10 nm Au film with Au crystals ~ 4 nm

16 The Hairy Ball Theorem and SAMs Self-Assembled Monolayers The hairy ball theorem Molecules in SAMs form a 2D crystal, that is a vectorial order. ne Vector Two Vectors 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. *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

17 Thermodynamic interpretation What is the Vectorial rder in SAMs? What is a topological sphere? W. D. Luedtke and Uzi Landman J. Phys. Chem. B, 102 (34), 6566,, 1998 Molecules in SAMs form a specific angle with the surface normal in order to maximize van derwaals interactions. ne can define a vector (from the attachment point to the projection of the molecular head group) to describe the molecular position. dodecane solution solution

18 Chemistry of chain formation 1. Pole functionalization with 11-Mercaptoundecanoic acid (MUA) Short reaction times allow functionalization only at the polar singularities HC H H 2. Two-phase reaction: interface-controlled stoichiometry Amide bonds Nanoparticles in toluene phase 1,6-Diaminohexane in water phase NH H 2 N 2 Nano-nylon Precipitation at the toluene-water interface indicates the formation of insoluble material Initial DeVries, Stellacci, Science 315, 358, 2007 Precipitate Final

19 Nano-Nylon Two-Phase TEM images 100 nm Nanoparticles Chains

20 Inter-Particle Distance Potential linker position Measured interparticle distance Potential EGDA linker conformation H S H S N N 5 H H 5 5 N H 9 N H 5 DAH theoretical length = 3.6 nm EGDA theoretical length = 9.6 nm

21 Chains of Big Particles

22 Acknowledgements Graduate Students Robert J. Barsotti, Jr. (now at Arkema. Senior Scientist) Gretchen A. DeVries Alicia M. Jackson A. Amy Yu (also at MGH, post doc) Tan Mau Wu Benjamin Wunsch sman Bakr (Harvard) Suelin Chen Jeffrey Kuna Sarah Thevenet zge Akbulut Jin Young Kim Hyewon Kim Jin-Mi Jung (KAIST) Ramona DallaPiccola (Trento) Post-Docs Markus Brunnbauer (now at Infineon, Senior Scientist) Xiaogang Bruno Liu (now at NUS, Assistant Professor) Brenda Long ktay Uzun Ying Yu Andrea Centrone Ayush Verma Kazuya Nakata Cedric Dubois Georg Heimel Collaborators David Nelson, Harvard Lucia Pasquato, Trieste Ralph Weissleder, Harvard, MGH Molly Stevens, Imperial C., UK Henry I. Smith, MIT Enzo difrabrizio, Catanzaro, Italy Anthony Guiseppe-Elie, C. Virginia Maurizio Prato, Trieste Marcus Halik, Erlangen U., Germany Anne Mayes, MIT Sharon Glotzer, U. Mich Joerg Lahan, U. Mich. Nicola Marzari, MIT Darrell Irvine, MIT Krystyn Van Vliet, MIT Robert Cohen, MIT Undergraduates Jacob M. Myerson ( now at MIT) Brian Netlner ( now at MIT) Angela Tong Nishi 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) NSF: NER DMI NIRT DMR NIRT SCP CAREER NIH TPEN Program Hewlett Packard Deshpande Center ACS-PRF Reed Foundation at MIT CMSE-MRSEC DMR Int. Copper Association MARC 3M Non Tenured Faculty Award 3M Innovation Award DuPont Young Professor Award Packard Foundation Award Mineral Technologies