Post on 11-Jan-2016
Evaluation of Microscopic Inhomogeneity in Solids Using Single
Molecules as Nanometer-sized Probes
Yoko MiyamotoMiyasaka Lab.
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ContentsI. Introduction
Single molecule detection: History and methods Single molecules as nano-probes in evaluating microscopic properties of materials
II. Single molecule imaging and its related techniquesWide-field microscopySingle molecule tracking
III. Evaluation of polymeric materials with SMIPrevious worksMy current research topic: Development of a multicolor detection system
IV. Summary
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History of Single Molecule Spectroscopy
• 1989 W. E. Moerner et al. First detection of single-
molecule with FM spectroscopy
• 1990 M. Orrit et al. Fluorescence excitation spectra
of single molecules
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Each guest molecule is in different environment.
The result of ensemble measurement
Emission spectrum of a single molecule
Different electronic state → Position-dependent spectrum and lifetime
Single molecule detection
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The motions of individual guest molecules strongly depend on microenvironment.
Tracking the motion of guests can provide information on microscopic properties of materials:
・ Nanostructures・ Mobility of guests (Free volume in polymer, Host-Guest Interaction, etc. ) ・ Spatial heterogeneity ....
Single molecules as nano-probes in evaluating microscopic properties of materials
2D, but very high spatial resolutionMany molecules can be observed at a time.
Wide-field Microscopy
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Single molecule tracking
bgsY
y
sX
xIyxf })(
2
1)(
2
1exp{),( 2121
0
sin)(cos)( 001 yyxxx
cos)(sin)( 001 yyxxy
Actual precision of tracking ~ 5-10 nm in our experimental set up
X0 = 274.03 +/- 0.0339 pixel
Y0 = 148.17 +/- 0.0351 pixel
Previous works:Visualization of nanoscale heterogeneity in pol y HEA films
Sample preparation using spin-casting method
Cover glass
Well cleaned cover glass
single molecule
Poly(2-hydroxyethylacrylate) [ polyHEA ]
N,N’-bis(2,6-dimethylphenyl) perylene-3,4,9,10-tetracarboxylic diimide
2.45 nm
1.22 nm
Trajectory (on glass substrate)
Time course of step size
Exp. Time: 500 ms
Nanoscale heterogeneity in the sample ?
Previous works:Visualization of nanoscale heterogeneity in pol y HEA films
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Exposure time ~ 30.5 msExposure time ~ 500 ms
Previous works:Visualization of nanoscale heterogeneity in pol y HEA films
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Exposure time: 30.5ms Silicon substrate
50 nm
100 nm
Previous works:Visualization of nanoscale heterogeneity in pol y HEA films
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Motivation of my workSMS can reveal the inhomogeneity of polymers.
HOWEVER,we cannot obtain the direct information on the relation between
the motions of the guest molecule and the host polymer.
dual-color imaging
Dye labeled polymer chain
Guest dye
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Dual-color single molecule tracking system
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① 励起側光学系
② 検出側光学系
Evaluation of system
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PMMA glass transition temperature (Tg) 82℃ → glassy state at room temperature
BPPBIN,N’-3,3-Dipropyl-1,6,7,12-tetrakis(4-tert-butylphenoxy)-3,4 : 9,10-tetracarboxylic diimide
OON
O
OO
O
N
OO
6μm
BPTDIN,N’-3,3-Dipropyl-1,6,7,12-tetrakis(4-tert-butylphenoxy)-terrylene-3,4:11,12-tetracarboxidiimide
O
N
O
O
N
O
N
O
O
O
N
O
800 750 700 650 600 550 500 Wave Length [nm]
吸収スペクトル 蛍光スペクトル
6μm
Evaluation of system
BPTDI BPPBI
15
-20
-10
0
10
20
x /
nm
806040200
number of frames6
5
4
3
2
1
0
Occ
uren
ce
-20 -10 0 10 20
Position[nm]
-20
-10
0
10
20
x /
nm
140120100806040200
number of frames8
6
4
2
0
Occ
uren
ce
20151050-5-10
Position[nm]
±20nm ±30nm
Poly (2-hydroxyethyl acrylate) (PolyHEA)
glass transition temperature (Tg) 17℃ → molecules show liquidity
Diffusion motions of guest molecules
BPPBIBPTDIDistribution of diffusion coefficient 16
14
12
10
8
6
4
2
0Num
ber
of O
ccur
renc
e
80x10-3604020Diffusion coefficient / m2s-1
14
12
10
8
6
4
2
0Num
ber
of O
ccur
renc
e
80x10-3604020
Diffusion coefficient / m2s-1
382
380
378
376
374
y / p
ixe
l
302826242220x / pixel
245
240
235
230
225
y / p
ixel
500495490485x / pixel
Summary• I have shown the significance of measuring single molecules
in evaluating microscopic properties of materials .
• Wide-field microscopy permitted the tracking of translational motions of individual molecules.
• To more clearly and precisely elucidate the relation between the motion of the guest molecule and that of the host polymer, we have developed a dual-color imaging system.
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Contents• Introduction -History of Single Molecule Spectroscopy -Difference between ensemble and single-molecule measurement -Information obtained only by SMS
• Measurement - Single-molecule detection - Wide-field Microscope and Confocal Microscope - Single-molecule tracking
• My work
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Glass substrate
Polymer film
Spin-coat method
Cover glass
Well cleaned cover glass
single molecule
Wide-field microscopy
Difference between ensemble and single-molecule measurements
An emission spectrum of a single molecule
The result of ensemble measurement
“Single molecule”
Ensemble
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~ 10 nm
PDI in PMMA (Tg ~ 355K, Mw 15000 )
Apparent diffusion coefficient < 4.0 × 10-5 m2s-1
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Loose area
fast diffusion Packed area
slow diffusion
Free volume distribution, permittivity, density, viscosity, elasticity, etc.
Information obtained only by SMS
Inhomogeneity in nanometer scale
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N,N’ -bis(2,6-dimethylphenyl)- perylene-3,4,9,10-tetracarboxylic diimide (PDI)
PA08 (Nissan Chemical inc. )(Anti-reflection layer in lithography)
(n 1.5)≒
Ethyl lactate solution ofPA08 ( 0.36 wt %)Irgacure 184 ( 0.022 wt %)
Irgacure184 ( Ciba specialty chemicals )
O
OR
OR
CH2OR
n
Photo-curable polymeric material
2000 rpm
UV light (2.6 w/cm2)
Jpn. J. Appl. Phys. 2007, 46, p7279.
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Trajectories(UV irradiation (325 nm) duration ~ 1 sec)
70% of PDI molecules: D dropped to < 0.002 μm2s-1.
The rest 30% could diffuse as freely as in the non-reacted sample.
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Wide-field microscopy Confocal microscopy
3-dimentianal resolutionSmall backgroundHigh temporal resolution
2-dimentianal resolutionMany molecules can be Observed at a time.High spatial resolution
Wide-field Microscope and Confocal Microscope
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