2. 1/35
1.
2.
3.
4.
5.

3. 2/35
-
100 km/h
1–2 nm
< nm
HDI

4. 3/35
MD
MD
F(r(t), (t))
F ! r(t + t), (t + t)

5. 4/35
MD
1–2 nm
μm
HDI
–

6. 5/35
o MD
o MD
Ø
Ø
Ø
MD

7. 6/35
o MD
o MD
Ø
Ø
Ø
MD

8. 7/35
Ø PFPE (perfluoropolyether)
Ø
X–O–[CF2CF2O]21[CF2O]21–X
Z X = CF3 Zdol X = CF2CH2OH
(111)

9. 8/35
COMPASS
• simulation 2.1 g/cm3, catalog 1.82 g/cm3
• simulation 29 mm2/s, catalog 100 mm2/s
F(r(t), (t))
F ! r(t + t), (t + t)

10. 9/35
ElectroStatic Potential (ESP) fitting
1.
2.
2.1 g/cm3 → 1.83 g/cm3 1.82 g/cm3
C
F
+δ
−δ
PFPE

11. 10/35
D0
R0
UH bond(r, ) = D0
ñ
5
✓
R0
r
◆12
6
✓
R0
r
◆10ô
cos4
r
θ
Donor oxygen
Acceptor oxygen
Hydrogen

12. 11/35
o
o
o

13. 12/35
o MD
o MD
Ø
Ø
Ø
MD

14. 13/35
→
Z C C O C O C C O
F
F
F
F
F
F
F
F
F
F
∙ ∙ ∙ O C
F
F
F C O
F
F
∙ ∙ ∙
F
F
C O FC C
F
F
F
F
Zdol C C O C O C C O
F
F
F
F
F
F
F
F
F
F
∙ ∙ ∙ O C C OH
F
F
H
H
C C O
H
H
F
F
HO ∙ ∙ ∙
(111)
4
dangling
bond
8–10
1/100

15. 14/35
DPD MD
ri, vi i
F C i
F D F S i
⇢
˙r =
m ˙ = FC
+ FD + FS
Ull Ull-p, Ulll-pa
Uls Uls-p, Ulls-pa
§
Uba
Ubl
Ubl
Uba
Ud
Ud
Uls
Uls
Uls
Ull
Ull-p
Ull
Ulll-pa
Ulls-paUls-p
Ull-p
Ull-p
§

16. 0
0.2
0.4
0.6
0.8
1
1.2
1.4
0 0.5 1 1.5 2
RDF,g(r)
distance, r [nm]
RDF
15/35
Iterative Boltzmann Inversion (IBI)
RDF g(r)
r
dr
r
RDF
RDF gref(r)
RDF g(r)
U(r) = kBT ln
g(r)
gref(r)
U +1
(r) = U (r) + U(r)
No

17. 16/35
–

18. 17/35
–

19. 18/35
Rgv
Rgp
2Rgp
2Rgv
r
Rgp = Rgv = Rg

20. 19/35
RDF
r = r + 2
⇥
Rg Rgp(r)
⇤
r
RDF IBI
RDF
RDF
–
–

21. 20/35
1
2

22. 21/35
Transverse DPD DPD
eij rij I
θij 1
ζ σ
DPD
Transverse DPD
FD
=
X
6=j
ƒD
j
, ƒD
j
= k
e jeT
j j
?
Ä
e jeT
j
ä
j
FS
=
X
6=j
ƒS
j
, ƒS
j
= k
e jeT
j j + ?
Ä
e jeT
j
ä
j
vij
rij
ζ
σ ζ
2
= 2kBT

23. 22/35
2
fitting
50 nm
1.5 nm
MD
30 ns

24. 23/35
APFPE–Disk = 4.7 10−20 J
A = 19.6 10−20 JC
H. Matsuoka, et al., Microsystem Technologies, 2005
Hamaker A
0.5 10−10 m2/s
Hamaker
-1
0
1
0.5 1 1.5
potential
potentialenergy[k
B
T]
distance, r [nm]
C
r6
C =
A
2
solid liq id

25. 24/35
o
o
§
• –
•
Transverse DPD•
§ Hamaker
o 1/100

26. 25/35
o MD
o MD
Ø
Ø
Ø
MD

27. 26/35
Ra [nm] [nm]
A 0.2 0.5
B 0.2 1.2
: Vshear = 10, 20, 50, 100 m/s
Height[nm]
1.0
−1.0
30 nm 60 nm
: h = 2.0 nm
z
Vshear/2
−Vshear/2
h
0
x

28. 27/35
= ˙
= ˙ ˙ = Vshe r/h
Ø A
B
Ø A
Ø B Zdol
Ø
=
˙
A
B

29. 28/35
Vshear = 50 m/s
A B
vx
−25 m/s
25 m/s
Ø A
Ø B Zdol
dvx/dz

30. 29/35
e =
˙e
= ˙
˙e = d /dz˙e = d /dz
Ø A
B
Ø
Ø
A
B

31. 30/35
B
Vshear = 50 m/s
A B

32. 31/35
Vshear = 50 m/s
A B
Zdol
Ø
Ø B

33. 32/35
Zdol, Vshear = 10 m/s
S+S P+P S+P S P
A B

34. 33/35
o
o
o

35. 34/35
o MD
§
§
o
§

36. 35/35
o
o
o

37. I.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Molecular Dynamics Simulations of Diffusion of
Submonolayer Polar Liquid Lubricant Films on Solid Surfaces,” Microsystem Technologies, Springer, Vol. 22,
pp. 1285-1290, 2016.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Coarse-Grained Molecular Dynamics Simulation of
Nanometer-Thick Polar Lubricant Films Sheared Between Solid Surfaces with Random Roughness,”
Transactions on Magnetics, IEEE Magnetics Society, Vol. 51, pp. 3300704, 2015.
II.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Temperature Dependency of Shear Properties of Nanometer-
Thick Liquid Lubricant Films: A Molecular Dynamics Study,” World Tribology Congress 2017, September 17-22,
Beijin(China), 2017.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Coarse-Grained Molecular Dynamics Study of Chemical
Structure effects on Shear Properties of Nanometer-Thick Lubricant Films,” International Symposium on Micro-
Nano Science and Technology 2016, December 16-18, Tokyo(Japan), 2016.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Effect of Molecular Chemical Structures on Shear Properties
of Nanometer-Thick Liquid Lubricant Films: A Coarse-Grained Molecular Dynamics Study,” 2016 STLE
Tribology Frontiers Conference, November 13-15, Chicago(U.S.), 2016.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Molecular dynamics simulations of diffusion of submonolayer
polar liquid lubricant films on solid surfaces,” 2015 JSME-IIP/ASME-ISPS Joint Conference on
Micromechatronics for Information and Precision Equipment, June 14-17, Kobe(Japan), 2015.
* T. Kobayashi, H. Zhang, K. Fukuzawa, S. Itoh, “Coarse-grained Molecular Dynamics Simulation of
Nanometer-thick Polar Lubricant Films Sheared between Solid Surfaces with Random Roughness,” IEEE
International Magnetics Conference 2015, May 11-15, Beijin(China), 2015.
III.
* , 2016.
* , 2015.
* MIPE AWARD 2015, 2015.