This document appears to be a collection of papers and presentations on molecular dynamics simulations of thin liquid lubricant films. It includes studies on the diffusion of submonolayer polar liquid films, the effect of temperature on shear properties, the impact of chemical structure and molecular properties, and shear behavior between rough surfaces. The document also lists several publications and presentations from 2015-2017 on these simulation works.

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.