Nanoindentation experiments were performed on a defect-free, molecular self-assembled monolayer of octadecyltrichlorosilane (OTS) on silicon using an interfacial force microscope (IFM). The IFM provided repeatable and elastic force profiles corresponding to the adhesive and compressive response of these 2.5nm thick monolayers. As a first step in the analysis of the force profiles, the OTS was assumed to be linearly elastic and isotropic, and adhesive interactions were accounted for via a cohesive zone model. However, the assumption of linearity gave rise to force profiles that did not match the measurements. As a result, the mechanical behavior of the OTS was extracted from molecular-dynamics simulations and represented as a hypoelastic material, which, when used in finite element analyses of the IFM experiments, was able to fully reproduce the force profiles. This suggests that the continuum representation of the mechanical and adhesive behavior of self-assembled monolayers may be directly obtained from molecular analyses.

1.
Kojio
,
K.
,
Ge
,
S.
,
Takahara
,
A.
, and
Kajiyama
,
T.
, 1998, “
Molecular Aggregation State of N-Octadecyltrichlorosilane Monolayer Prepared at an Air/Water Interface
,”
Langmuir
0743-7463,
14
, pp.
971
974
.
2.
Ulman
,
A.
, 1991,
An Introduction to Ultra Thin Organic Films From Langmuir-Blodgett to Self-Assembly
,
Academic
, New York.
3.
Ulman
,
A.
, 1996, “
Formation and Structure of Self-assembled Monolayers
,”
Chem. Rev. (Washington, D.C.)
0009-2665,
96
,
1533
1554
.
4.
Zhuk
,
A. V.
,
Evans
,
A. G.
,
Hutchinson
,
J. W.
, and
Whitesides
,
G. M.
, 1998, “
The Adhesion Energy Between Polymer and Self-Assembled Monolayers
,”
J. Mater. Res.
0884-2914,
13
,
3555
3564
.
5.
Reedy
,
E. D.
, Jr.
,
Kent
,
M. S.
, and
Moody
,
N. R.
, 2002, “
On the Relationship Between the Molecular Work of Separation and Interfacial Fracture Toughness
,”
Proc. of 26th Annual Meeting of the Adhesion Society
, Myrtle Beach, SC, pp.
502
504
.
6.
Mello
,
A. W.
, and
Liechti
,
K. M.
, 2004, “
Controlling Mixed-Mode Interfacial Fracture Toughness With Self-Assembled Monolayers
,” (submitted to ASME App. Mech.), Engineering Mechanics Research Laboratory Report EMRL #03-10.
7.
Maboudian
,
R.
,
Ashurst
,
W. R.
, and
Carraro
,
C.
, 2002, “
Tribological Challenges in Micromechanical Systems
,”
Tribol. Lett.
1023-8883,
12
,
95
100
.
8.
B.
Bhushan
, 1999,
Principles and Applications of Tribology
,
Wiley
, New York, p.
739
.
9.
Mayer
,
T. M.
,
Elam
,
J. W.
,
George
,
S. M.
,
Kotula
,
P. G.
, and
Goeke
,
R. S.
, 2003, “
Atomic-Layer Deposition of Wear-Resistant Coatings for Microelectromechanical Devices
,”
Appl. Phys. Lett.
0003-6951,
82
,
2883
2885
.
10.
Romrig
,
A. D.
Jr.
,
Dugger
,
M. T.
, and
McWhorter
,
P. J.
, 2003, “
Materials Issues in Microelectromechanical Devices: Science, Engineering, Manufacturability and Reliability
,”
Acta Mater.
1359-6454,
51
,
5837
5866
.
11.
Houston
,
J. E.
, and
Kim
,
T.
, 2000, “
Separating Mechanical and Chemical Contributions to Molecular-Level Friction
,”
J. Am. Chem. Soc.
0002-7863,
122
,
12045
12046
.
12.
Carpick
,
R. W.
,
Agraït
,
N.
,
Ogletree
,
D. F.
, and
Salmeron
,
M.
, 1996, “
Variation of the Interfacial Shear Strength and Adhesion of a Nanometer-Sized Contact
,”
Langmuir
0743-7463,
12
,
3334
3340
.
13.
Winter
,
R. M.
, and
Houston
,
J. E.
, 1998(a), “
Interphase Mechanical Properties in an Epoxy-Glass Fiber Composites as Measured by Interfacial Microscopy
,” in
Proc. of SEM Spring Conf. on Experimental and Applied Mechanics
, Houston.
14.
Winter
,
R. M.
, and
Houston
,
J. E.
, 1998(b), “
Nanomechanical Properties of the Interphase in Polymer Composites as Measured by Interfacial Force Microscopy
,”
Materials Research Society Spring Meeting
, San Francisco.
15.
Thomas
,
R. C.
,
Houston
,
J. E.
,
Crooks
,
R. M.
,
Kim
,
T.
, and
Michalske
,
T. A.
, 1995, “
Probing Adhesion Forces at the Molecular Scale
,”
J. Am. Chem. Soc.
0002-7863,
117
(
13
),
3830
3834
.
16.
Cabibil
,
H.
,
Celio
,
H.
,
Lozano
,
J.
, and
White
,
J. M.
, 2001, “
Nanomechanical Properties of Polysiloxane-Oxide Interphases Measured by Interfacial Force Microscopy
,”
Langmuir
0743-7463,
17
,
2160
2166
.
17.
Wang
,
M.
,
Liechti
,
K. M.
, and
White
,
J. M.
, 2004, “
Nanoindentation of Polymeric Thin Films With an Interfacial Force Microscope
,”
J. Mech. Phys. Solids
0022-5096,
52
,
2329
2354
.
18.
Joyce
,
S. A.
, and
Houston
,
J. E.
, 1991, “
A New Force Sensor Incorporating Force-Feedback Control for Interfacial Force Microscopy
,”
Rev. Sci. Instrum.
0034-6748,
62
(
3
),
710
715
.
19.
Houston
,
J. E.
, and
Michalske
,
T. A.
, 1992, “
The Interfacial-Force Microscopy
,”
Nature (London)
0028-0836,
356
,
266
267
.
20.
Johnson
,
K. L.
,
Kendall
,
K.
, and
Roberts
,
A. D.
, 1971, “
Surface Energy and the Contact of Elastic Solids
,”
Proc. R. Soc. London, Ser. A
1364-5021,
324
,
301
313
.
21.
Derjaguin
,
B. V.
,
Muller
,
V. M.
, and
Toporov
,
Y. P.
, 1975, “
Effect of Contact on the Adhesion of Particles
,”
J. Colloid Interface Sci.
0021-9797,
53
,
314
326
.
22.
Maugis
,
D.
, 1992, “
Adhesion of Spheres: The JKR-DMT Transition Using a Dugdale Model
,”
J. Colloid Interface Sci.
0021-9797,
150
,
243
269
.
23.
Siepman
,
J. L.
, and
McDonald
,
I. R.
, 1993, “
Monte Carlo Simulation of the Mechanical Relaxation of a Self-Assembled Monolayer
,”
Phys. Rev. Lett.
0031-9007,
70
(
4
),
453
456
.
24.
Tupper
,
K. J.
,
Colton
,
R. J.
, and
Brenner
,
D. W.
1994, “
Simulations of Self-Assembled Monolayers Under Compression: Effect of Surface Asperities
,”
Langmuir
0743-7463,
10
,
2041
2043
.
25.
Tupper
,
K. J.
, and
Brenner
,
D. W.
, 1994, “
Compression-Induced Structural Transition in a Self-Assembled Monolayer
,”
Langmuir
0743-7463,
10
,
2335
2338
.
26.
Henda
,
R.
,
Grunze
,
M.
, and
Pertsin
,
A. J.
, 1998, “
Static Energy Calculations of Stress-Strain Behavior of Self-Assembled Monolayers
,”
Tribol. Lett.
1023-8883,
5
,
191
195
.
27.
Wang
,
M.
,
Liechti
,
K. M.
,
Wang
,
Q.
, and
White
,
J. M.
, 2004, “
Self-Assembled Silane Monolayers: Fabrication With Nanoscale Uniformity
,”
Langmuir
0743-7463,
21
, pp.
1848
1857
.
28.
Smith
,
W.
, and
Forester
,
T. R.
, 1996, “
DḺPOLY̱2.0: A General-Purpose Parallel Molecular Dynamics Simulation Package
,”
J. Mol. Graphics
0263-7855,
14
(
3
),
136
141
.
29.
Stevens
,
M. J.
, 1999, “
Thoughts on the Structure of Alkylsilane Monolayers
,”
Langmuir
0743-7463,
15
,
2773
2778
.
30.
Allen
,
M. P.
, and
Tildesley
,
D. J.
, 2002,
Computer Simulations of Liquids
,
Clarendon Press
, Oxford.
31.
Frenkel
,
D.
, and
Smit
,
B.
, 2002,
Understanding Molecular Simulation: From Algorithms to Applications
, 2nd Ed.,
Academic Press
, San Diego.
32.
Jorgensen
,
W. L.
,
Madura
,
J. D.
, and
Swenson
,
C. J.
, 1984, “
Optimized Intermolecular Potential Functions for Liquid Hydrocarbons
,”
J. Am. Chem. Soc.
0002-7863,
106
(
22
),
6638
6646
.
33.
Jorgensen
,
W. L.
, and
Tirado-Rives
,
J.
, 1988, “
The OPLS Potential Functions for Proteins, Energy Minimizations for Crystals of Cyclic Peptides and Crambin
,”
J. Am. Chem. Soc.
0002-7863,
110
(
6
),
1657
1666
.
34.
Jorgensen
,
W. L.
, 1986, “
Optimized Intermolecular Potential Functions for Liquid Alcohols
,”
J. Phys. Chem.
0022-3654,
90
(
7
),
1276
1284
.
35.
ABAQUS/Standard User’s Manual, Version 6.4
, Hibbitt,
Karlsson and Sorensen, Inc.
36.
Simmons
,
G.
, and
Wang
,
H.
, 1971,
Single Crystal Elastic Constants and Calculated Aggregate Properties: A Handbook
,
2nd ed.
,
M.I.T. Press
, Cambridge, MA.
You do not currently have access to this content.