Organic Materials Chemistry · 2013-07-18 · the napthopyran as the molecular shape becomes planar...

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Organic Materials

Chemistry

Charles Lee

Program Officer

AFOSR/RTD

Air Force Research Laboratory

Date: 7 Mar 2013

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4. TITLE AND SUBTITLE Organic Materials Chemistry

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13. SUPPLEMENTARY NOTES Presented at the AFOSR Spring Review 2013, 4-8 March, Arlington, VA.

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2 DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution

2013 AFOSR SPRING REVIEW

NAME: Charles Lee

BRIEF DESCRIPTION OF PORTFOLIO:

To exploit the uniqueness of organic/polymeric materials

technologies for enabling future capabilities currently unavailable by

discovering and improving their unique properties and processing

characteristics

LIST SUB-AREAS IN PORTFOLIO:

Photonic Polymers/Organics

Electronic Polymers/Organics

Novel Properties Polymers/Organics

NanoTechnology


Organic Materials Chemistry

Research Objective and Challenges To exploit the uniqueness of organic/polymeric materials technologies

for enabling future capabilities currently unavailable by discovering

and improving their unique properties and processing characteristics

Challenges:

- Discover New Properties

- Control Properties

- Balance Secondary Properties

Approach:

–Molecular Engineering

–Processing Control

–Structure Property Relationship

• Program Focused on developing New and Controlled Properties

• Not applications specific, but often use applications to guide the

properties focuses

0

0.5

1

1.5

2

2.5

3

3.5

0 200 400 600 800 1000

Tensile Modulus (GPa)

Com

pre

ssiv

e S

trength

(G

Pa)

Pitch Based Carbon Fibers PAN Based Carbon Fibers

4

Self Assembled Micelle vs Covalently Bonded

Micelle for Nanoparticle Synthesis Zhiqun Lin, Georgia Tech

Fe2O3 Small Molecule Block Co-Polymer Star-Like Molecule

Diameter (nm) 16±1.49 10.8±2.98 10.1±0.5

Grams/L 2.94 1.81 36.2

# Particles/L 2.6×1017 6.6×1017 1.3×1019

Crown Core

Star-Like Micelle

Small Molecule Block

CoPolymer

Star-Like

Molecule

Au – Diameter (nm) 9±0.44 13±2 10.1±0.3

Grams/L 5.11 0.56 20.2

# Particles/L 6.9×1017 2.5×1016 2.0×1018

Pt - Diameter (nm) 73±5.74 6.0±0.98 6.2±0.2

Grams/L 4.86 0.86 26.3

# Particles/L 1.1×1015 3.6×1017 1.1×1019

Fe2O3–Diameter (nm) 16±1.49 10.8±2.98 10.1±0.5

Grams/L 2.94 1.81 36.2

# Particles/L 2.6×1017 6.552×1017 1.3×1019

Cd-Se-Diameter (nm) 8.5±0.65 ----- 9.9±0.3

Grams/L 0.98 ----- 22.8

# Particles/L 5.2×1017 ----- 7.5×1018

PbTiO3-Diameter (nm) ----- 50±4.9 9.7±0.4

Grams/L ----- 2.12 31.2

# Particles/L ----- 4.1×1015 7.5×1018

5 DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution 5

NPs Synthesis by Novel Amphiphilic

Star-Like Block Copolymers as

Template


Core/Shell Nanoparticles –

with Large Lattice Mismatch

DFe3O4 = 6.1±0.3 nm (core)

DPbTiO3 = 3.1±0.3 nm (shell)

Core/shell nanostructures are

conventionally obtained by dissimilar

materials epitaxy, which requires

moderate lattice mismatches (<2%)

between the two different materials in

order to obtain high-quality core/shell

heterostructures, which would

otherwise be difficult to obtain.

Fe3O4/PbTiO3

Despite more than 40% lattice mismatch between Fe3O4 and PbTiO3, Fe3O4/PbTiO3

core/shell nanoparticles can be readily crafted by this approach!!!


Hollow Nanoparticles

– Au Nanoparticles

Hollow noble metal

nanoparticles are the subject of

intense research for use in

bioimaging, photothermal

therapy, drug delivery, etc.

The thickness of Au

= 3.2±0.3nm

The diameter of hollow core

= 5.6±0.4nm

Janus Nano-Particles


Phototropic liquid crystals Tim White, Tim Bunning, AFRL/RX

“Phototropism”: A term used to describe light induced phase changes in liquid crystals.

An example of light induced order-disorder:

365 nm

Azo-NLC Nematic

Azo-NLC Isotropic

“Negative” phototropism – S (order parameter) decreases with light


In this case of “positive” phototropism, illumination increases the compatibility of the napthopyran as the molecular shape becomes planar and quasi-rod like aligning favorably with the liquid crystalline phases.

365 or 405 nm

Dark

“Closed form” “Open form”

Light Induced Disorder-Order in

Napthopyran (AMI15)/LC Mixtures

• New class of photochromic molecules that increase order upon light exposure employed for disorder-order transitions.

• Demonstration of full gamut of Light Induced Phase Transitions


AMI15/8CB Mixture

Shows Additional Transition

“Positive” phototropism – S (order parameter) increases with light

32.0 °C 32.0 °C

Nematic Smectic A

32.0 °C

Nematic

AMI15/8CB shows Photoinduced

• Isotropic to Nematic Transition

• Nematic to Smectic A Transition

8CB

40.3 °C 40.3 °C

Isotropic Nematic

40.3 °C

Isotropic

Before light With light (365 nm) After light

T. Kosa, L. Sukhomlinova, L. Su, B. Taheri, T.J. White, and T.J. Bunning,” Light Induced Liquid Crystallinity",

Nature, 2012, 485, 347-349.


Different Phase Change

with Chiral Dopant

400 500 600 700 800 9000

20

40

60

80

100

Tra

nsm

iss

ion

(%

)

Wavelength (nm)

After irradiation – sample becomes both absorptive and reflective

~ 6 wt% R1011

Before irradiation – sample completely transmissive in VIS and NIR

R1011 – a chiral dopant from Merck

5CB

Before light With light (365 nm) After light

Data collected at AFRL/RX

Data collected at AFRL/RX

AMI15/5CB/R1011 Mixture shows Photoinduced:

• Isotropic to Cholesteric Phase Transition


400 500 600 700 800

0.00

0.25

0.50

0.75

1.00

Norm

aliz

ed T

ransm

issio

n

Wavelength (nm)

No dichroism evident in isotropic state

400 500 600 700 800

0.00

0.25

0.50

Ab

so

rba

nce

(a.u

.)Wavelength (nm)

E//N

EN

Dichroism in nematic phase

The mixture changes color and becomes polarized at the same time

(Plain Glasses become Polarized Sunglasses)

Naphthopyran Phototropic Mixtures

Unprecedented “Photo-dichroism”

For the Isotropic to Nematic Transition in AMI15/5CB Mixtures, Dramatic light induced changes in dichroic ratio from ~0 to 0.722


COE Georgia Tech/AFRL

Joint Project • To craft novel organic-inorganic nanocomposites composed of

Superparamagnetic Iron Oxide Nanoparticles (SPION) intimately and

permanently connected with nematic liquid crystals (LCs) and chiral

azo molecules with high helical twisting power (HTP) for many

potential applications.

potential for application in communication devices, molecular devices, light-controllable

devices, optical display system, optical data recording, photo-optical triggers, polarizers,

and reflectors, and electromagnetic sensors, etc.

With light (365 nm) After light

365 or 405 nm

Dark

“Closed form” “Open form”

Kosa and White et. al, Nature, 2012, (485), 347–349.

Color switching

Light –induced liquid crystallinity


One-Dimensional Palladium Wires Tobias Ritter (YIP), Harvard U

Background on 1-D Metal Chains:

• Solid-state mixed-valence 1-D chains with Metal–Metal bonds

• Aqueous mixed-valence oligomers

Mixed-valence (d7-d8) oligomers: Pt blues,

Ir blues, Rh oligomers.

[Rh2(bridge)4]26

[Rh2(TMB)4]2+

H2SO4

H2O

[Rh2(TMB)4Rh2(bridge)4Rh2(bridge)4]8

[Rh2(TMB)4Rh2(bridge)4Rh2(bridge)4]216

12 Rh Atom Chain -- longest 1-D metal chainpreviously characterized

Chem. Ber. 1908, 41, 312.

Science 1982, 218, 1075.

Coord. Chem. Rev. 1999, 182, 263.

Angew. Chem. Int. Ed. 2001, 40, 4084.

J. Am. Chem. Soc. 1981, 203, 2220.

N N

C C

"bridge":

N N

C C

" T MB " :

Angew. Chem. Int. Ed. 1969, 8, 35.

Angew. Chem. Int. Ed. 1996, 35, 2772.

J. Organomet. Chem. 2000, 596, 130.

Inorg. Chem. Commun. 2001, 4, 19.

-There are a few reports of infinite 1-D

chains in the solid state with metal–metal

bonds.

-Not solution stable; Solid-state syntheses • take several days or weeks • low yield (usually 50% or less) • small scale (< 100 mg)


N

N

Pd O

O

Pd O

OMe

Me

n

nF

N

N

PdO

O

PdO

OMe

Me

N

N

PdO

O

PdO

OMe

Me

XeF2 (1 eq.)CH2Cl2, –50 °C97%

1.00 g

1.04 g

New Chemistry – Solution

Processible Palladium Wires

From Dimers to Wires:

• Infinite Pd chains in solid state revealed by X-ray crystallography

• Rapid, High-Yielding, Gram-Scale, Solution-Phase Synthesis

PhICl2CH2Cl2-30 °C

Pd-Pd Bond Formation

N

N

PdO

O

PdO

OMe

Cl

Cl

Me

N

N

Pd O

O

Pd O

OMe

Me

Oxidation of dipalladium(III) complexes with coordinating

anions (Cl–) leads to Pd dimers with covalent bond

between the metal atoms.

The polymerization occurs in solution in less than 5 minutes, giving pure material on large scale


• Lengths up to 750 nm

(>1,300 Pd atoms)

observed in solution

• The longest solution-

stable metal–metal bonded

chain previously reported

with assigned length

contains 12 metal atoms‡.

• Choice of counter-Anion

controls chain length

• Enabled efficient device

fabrication, not possible

with previous 1-D wires

Nature Chem. 2011, 3, 949–953. ‡J. Am. Chem. Soc. 1981, 203, 2220–2225.

Solution Stable 1-Dimensional

Palladium Wire 1-D metal wires are predicted to display room

temperature superconductivity n

n FN

N

PdO

O

PdO

OMe

Me

III

III

Semiconductor350 nm length

(>600 Pd

atoms)

750 nm length

(>1,300 Pd

atoms)


Thin-Film Conductivity:

• Solution processing capabilities allow for thin-film coating

• Four-point probe device used to measure conductivity of 1-D wire polymers film

n

n FN

N

PdO

O

PdO

OMe

Me

III

III

Semiconductor

Nature Chem. 2011, 3, 949–953.

Devices were fabricated

using thin films of the 1-D

wire polymers, which

could be deposited from

dichloromethane solutions

either by drop casting or

spin coating.

Four Point Probe Measurement


Tuning of Electronic Properties

5

6

7

8

9

10

0.0037 0.0039 0.0041 0.0043

ln(C

on

du

ctan

ce)

1/T (1/K)

n

n FN

N

PdO

O

PdO

OMe

Me

III

III

Semiconductor

bandgap = 1 eV

Nature Chem. 2011, 3, 949–953

Shorter chains with

more coordinating

fluoride anions display

higher bandgap

Longer chains with less

coordinating BF4

anions display lower

bandgap

bandgap = 0.7 eV

8

9

10

11

12

0.0035 0.00375 0.004 0.00425 0.0045

ln(C

on

du

ctan

ce)

1/T (1/K)

Tuning Flexibility: • Side Group Solubility

• Counter Ion

• Pd Oxidation State

5

6

7

8

9

10

0.0037 0.0039 0.0041 0.0043

ln(C

on

du

ctan

ce)

1/T (1/K)

n

n FN

N

PdO

O

PdO

OMe

Me

III

III

Semiconductor

bandgap = 1 eV

0.5n

0.5n FN

N

PdO

O

PdO

OMe

Me

2.5

2.5

Metallic ConductorAbove 200 K

Films based on Pd(III)

wires display

semiconductivity, with

adjustable bandgap.

Films based on

Pd(2.5)display the

first example of a

transition to a

metallic state

observed at ambient

pressure for a

polymer based on 1-D

metal wires.

Solution-stable 1-D metal wires with tunable conductive properties may have an

impact on areas such as:

• Next-Generation Solar Cells

• Molecular Sensors

• Molecular Wires for Nanoscale Circuits


Power Generation with Body Heat Choongho Yu & Jaime Grunlan, Texas A&M

First demonstration of electricity generation from polymeric materials

Flexible TE polymers

Connected to

a multimeter

Cut by

scissors

Voltage –Time response

Voltage

Time

20 DISTRIBUTION STATEMENT A – Unclassified, Unlimited Distribution T(K)

0 5 10 15 20 25

Voltage (

mV

)

0

1

2

3

4

5

6

7

1 junction

2 junctions

3 junctions

T(K)

0 5 10 15 20 25

Pow

er

(nW

)

0

5

10

15

20

25

1 junction

2 junctions

3 junctions

Air-stable fabric thermoelectric modules made of

n & p-type composites

Voltage output vs Temperature

(1) Flexible composite (2) Module fabrication

N-type P-type

(3) Multiple junctions in series

1.4 mm

Power output vs Temperature

Voltage and

power are being

increased by:

(a) stacking more

layers;

(b) connecting

more modules

Carbon

nanotubes

+ Paper

(cellulose

fibers)

Carbon

nanotubes +

Poly-

ethyleneimeine

(PEI) +

NaBH4 treatment


Improving Power Factor by Tuning P-type

composites with multiple CNT stabilizers

Double-walled carbon nanotubes (DWNT) are

stabilized with two different molecules in poly(vinyl

acetate) latex:

PEDOT:PSS (conductive)

TCPP (semi-conductive)

50

60

70

80

90

100

0

30,000

60,000

90,000

120,000

150,000

0 10 20 30 40 50

See

bec

k C

oef

fici

ent

(μV

/K)

Ele

ctri

cal

Co

nd

uct

ivit

y (

S/m

)

DWNT Concentration (wt%)

Electrical Conductivity

Seebeck Coefficient

0

250

500

750

1,000

1,250

1,500

0 10 20 30 40 50

Pow

er F

act

or

(μW

/(m

·K2))

DWNT Concentration (wt%)

Highest PF ever

reported for fully

organic composite

at ~500

μW(m·K2)!

Electrical conductivity increases with DWNT

concentration; while the Seebeck coefficient remains

relatively insensitive.

The power factor (S2σ) increases with DWNT concentration and

is within an order of magnitude of traditional inorganics (maroon

shaded region).


Different Module Design Concept David Carroll, Wake Forest U.

Using Different CNT Compositions and TE Module Concept

The garment has recently been shown on

CNN International, CNBC, and the

Discovery Channel.


• Laser Refraction

• Optical Signal Processing

• Wave Front Correction

• 3D Holographic Display

• Image Correlation

Photorefractive Polymers Multi-TD’s Interests


Two Beam Coupling Optical Correlation Jed Khoury AFRL/RY (11RY01COR)

Cross Correlation in Signals with Cluttered Background

and Poor Discrimination are Issues in Target Recognition

Applications

Breakthrough in Correlation Filter

Success due to Two Efforts

1. The holographic, dynamic range

compression developed by

AFRL/RY (Jed Khoury)

2. Organic photorefractive material

that was developed by University

of Arizona/Nitto Denko

Both efforts funded by AFOSR

George Asimellis Charles Woods Jed Khoury Bahareh Haji-saeed


Computer Simulation Comparing Two-Beam

Coupling Correlation vs SOA Correlation Algorithms

Yaroslavsky

Matched filter Phase-only filter

Two Beam Coupling

Compression filter Input

Using input that has a lot of background

noise, Two Beam Coupling Correlation is:

• 1.5X better than Yaroslavsky Optimal filter

• 10X better than Phase-only filter

• superior to Matched filter (failed to

recognize target)

No correlation filter in the last 50 years, since the first correlation invented by

Vander Lugt (1963), have been designed that can improve simultaneously the

discrimination, the signal-to-noise ratio, and the peak-to-noise ratio.

But the scheme will require very large beam ratio, that will require a

photorefractive material that has very high diffraction efficiency.

L L

Input

PR CCD


BULK PHOTOREFRACTIVE CORRELATION VS

THIN FILM PR POLYMER CORRELATION Jed Khoury, AFRL/RY

Arcs instead of full rings due asymmetric

dephasing

Thick arc line due broad impulse response

Only first order correlation peaks

Bulk

photorefractive Thin film photorefractive

polymer

Many orders

Sharp narrow symmetric

Asymmetric

Thick

one

order

broad

Input Image

Full rings, nearly symmetric due to

Negligible dephasing factor in thin film polymer

Narrow rings lines due narrow impulse

response with thin photorefractive polymer

Very narrow and sharp correlation peak due

Narrow impulse response

Numerous correlation orders due very small

dephasing

A Thick BSO Crystal

Point source

(δ-function input)

A Thin Nitto Denko Organic Material

Thick diffracted beam

(Broad impulse response )

Point source

(δ-function input)

Thin diffracted beam

(Narrow impulse response )

Dephasing Factor is small in thin film holographic materials.


Two Beam Coupling Experiment

with PR Polymer Thin Film(1)

Input Data


Two Beam Coupling Experiment

with PR Polymer Thin Film (2)

Input Data


Applied to Synthetic

Aperture Radar Data

C C C C C

CC CC CC CC CC

CC CC CC CC CC

C Reference

template

Target

Low

resolution

images

synthesized

from

the MSTAR

data base

Dynamic range compression increases

The first correlation filter that can improve simultaneously the

• SNR (100X)

• PNR,

• Discrimination (3 orders of Magnitude)

Correlation filter that outperforms optimal digital correlation filters

Material Chemistry Makes It Possible!!!


Portfolio Trends

Decreasing Emphases:

-Organic Solar Cells

-Organic Transistors

Increasing Emphases:

-Self Assembly in Solid State

-Radical, Spin and Excited State Controlled

Properties


Flexible Photodetector

Summary

• Program Focused on developing New and Controlled Properties

• Not applications specific, but often use applications to guide

the properties focuses

• Scientific Challenges

- Discover New Properties

- Control Properties

- Balance Secondary Properties

• General Approaches

- Molecular Design

- Processing Control

- Establish Structure Properties Relationship

Organic Materials Chemistry · 2013-07-18 · the napthopyran as the molecular shape becomes planar...

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Transcript of Organic Materials Chemistry · 2013-07-18 · the napthopyran as the molecular shape becomes planar...