1. Manipulation of Multiwall Nanotubes (MWNT) and Study of Frictional Interaction with Surfaces
Dana Research Centre, NEU
11/10/2018

2. Points of Discussion Dana Research Centre, NEU
Motivation to study Carbon Nanotube surface interaction
How was it accomplished?
Surfaces Analyzed
Experimental Data Extraction
Experimental and Theoretical Match
Data Analysis
Conclusion and Future Work
Dana Research Centre, NEU
11/10/2018

3. Carbon Nanotubes (CNT’s)
Arm Chair Structure Zigzag Structure
Arm Chair  Metallic Nature
Zigzag  Semiconducting Nature
High Current Densities  1010 A/cm2
High Mechanical strength  Carbon bonding stronger than Diamond
Z. Yao, et al Phys. Rev. Lett. 84, 2941 (2000)
Dana Research Centre, NEU
11/10/2018

4. CNT Applications and Motivation
SWNT electromechanical switches by CHN
Switch Actuation leads to NT–SiO2 interface slip
AFM used to Characterize the slip
P Ryan et al, J. Micromech. Microeng. 21 (2011)
NEMS Oscillators NEMS Memory Devices
Metallic Nanotube, RTSET by AFM manipulation.
NTs between Au electrodes on top of a Si/SiO2 substrate
Strong bends act as tunnel barriers for electron transport
AFM Manipulation is simple and effective
AFM Manipulation is a reversible process
Ch. Postma.et al, SCIENCE VOL JULY 2001
RTSET = Room Temperature Single Electron Transistor; NT = Nanotubes;
SWNT = Single Wall Nanotube , CHN = Center for High Rate Nanomanufacturing
NEMS = Nanoelectromechanical Systems ; AFM = Atomic Force Microscopy
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11/10/2018

5. CNT Interaction with Surfaces 
Straightening the tube
Bending the tube
AFM controls the shape and position of individual MWNT dispersed on a surface
AFM can straighten, bend and under certain conditions cut nanotubes.
AFM manipulations are feasible due to the interaction between nanotubes and the substrate
Estimation of CNT Binding energy with the surface
Tobias Hertel, et al. J. Phys. Chem. B, Vol. 102, No. 6, 1998 
Cutting the tube
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11/10/2018

6. AFM as Nanomanipulation Tool
SEM Image of AFM Cantilever
Si N-type Cantilever
Cantilever Stiffness = 2 N/m
Frequency = 70 kHz;
Tip Radius < 10 nm;
AFM System Accessories
Acoustic Enclosure
Active Vibration Table
Control Commands and Data Acquisition
Scan area display
Control Electronics
AFM System
Optical Microscope
Laser Alignment
XY Scanner
Z Scanner
Scan Head
PSIA XE-150 AFM
at CHN, NEU
First to introduce Cross talk
elimination in the XE series
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11/10/2018

7. Theoretical Modeling Dana Research Centre, NEU 11/10/2018
Final CNT Deformed shape
Case A (load 50% length) Case B (At 40% Length) Case C (30% Length)
Modeling based on equilibrium bent elastic rod equation
Equation realized in MATLAB to generate range of shear stress curves
E = Young’s Modulus
I = Second Moment of C/s area; D = Diameter of the tube
b = Effective Contact width with the surface; α = 0.05D
Palaniappan Nagappan , Journal of Tribology, JULY 2009, Vol. 131
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11/10/2018

8. Previous Manipulation Work
Original CNT
Manipulated CNT
Small Aspect Ratio tubes (Length / Diameter)
Lesser degree of deformation
Manipulation Vector Position away from CNT mid point
Curve fitting based on eye coordination
Parameter ‘α’ taken as 0.6 arbitrary
Only SiO2 surface manipulation
VIDYARANYA RAMPURKAR, NEU 2009
Experimental and Theoretical Curve Fitting
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11/10/2018

9. Estimation of Shear Stress
Numerical Calculation for Estimation of Shear Stress
CNT Structural Parameters, Diameter (D) and Length (L) of nanotube extracted from AFM Imaging tool (XEI)
Aspect Ratio (A) = Length/ Diameter
Effective contact width (B)
Elastic Young’s Modulus (E) = 1Tpa
Cross-sectional moment of Inertia (I), I = Π/64 (D4)
Dimensionless shear stress (τ), Determined from the Range of curves
Shear Stress (Mpa)
Dana Research Centre, NEU
11/10/2018

10. CNT Selection and Solution Preparation
CNT’s selected are near perfect straight ones
Wide Range of Aspect ratio Nanotubes (80<A<653)
Production by Arc Discharge Method
Production method yields High Percentage of impurities
CNT Solution preparation with IPA and DMF for better
solubility
TEM images of (a) an arc-MWNT, (b) a CVD-MWNT.
Salvetat JP et al, Adv Mater 1999;11(2):161–5
CNT Solution in DI water
CNT Solution in IPA
CNT Solution in DMF
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11/10/2018

11. Manipulation Procedure
Original CNT Imaged in the Non contact mode operation
Desired Aspect Ratio (>80) CNT selected
CNT is dragged according to the vector drawn in Contact Mode Operation
Vector drawn very close to midpoint , long enough and normal to the CNT to achieve effective deformation shape
After manipulation, Imaging done again in Non contact Mode
Sometimes after manipulation imaging is done several times to locate the deformed CNT
Collected AFM Images are processed by XEI software
Mithun Chandrasekar, NEU 2012
Original CNT
Manipulation Vector
Manipulated CNT
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11/10/2018

12. CNT Length Determination
CNT Length: 3.9µm
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11/10/2018

13. CNT Diameter Determination
3 Point Diameter Measurement  Better Accuracy, offset subtraction
CNT Diameter: 16nm
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11/10/2018

14. Experimental Curve Extraction
Blue line is a benchmark of the manipulation vector
Image contrast is increased for better curve tracing
CNT deformed shape is traced with Microsoft curve drawing tool
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11/10/2018

15. Experimental and Theoretical Fit
Based on the Experimental curve extracted,
appropriate range of MATLAB curves are generated
Experimental curve with its vector (Blue line) is
mapped to the theoretically generated MATLAB
curves
Vector as reference line is centered on the 0 x
coordinate to determine the deformed CNT shape
value
0.48 represents the length ratio of the CNT, where
the load is applied.
Non uniform deformation, one side has curved
more than the other.
Curve around the drag point and one of the sides
does provide sufficient fit.
τ: 350
Increasing value of shear stress
Experimental and Theoretical Fits
Dana Research Centre, NEU
11/10/2018

16. Shear Stress Calculation
Length (L): 3.9µm; Diameter (D): 16nm;
Aspect Ratio (A): , Force Applied: 570.8nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ- = τ EI / BL3 = τ E П / 0.05*64*A3
Dimensionless Shear Stress (τ): 350
Calculated Frictional Shear Stress (τ-): MPa
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11/10/2018

17. Manipulation Example on SiO2
SIO2 Substrate
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11/10/2018

18. Manipulation Procedure
Original CNT
After Manipulation
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11/10/2018

19. CNT Length Measurement
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11/10/2018

20. CNT Diameter Measurement
Diameter: 12nm
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11/10/2018

21. Experimental Curve Extraction
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11/10/2018

22. Experimental and Theoretical Fit
Increasing value of Shear Stress
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11/10/2018

23. Shear Stress Calculation
Case 1: Length (L): 1.2µm; Diameter (D): 12nm; Aspect Ratio (A): 100, Force Applied: nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г E П / 0.05*64*A3
Dimensionless Shear Stress : 450
Calculated Frictional Shear Stress: 441.7MPa
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11/10/2018

24. Manipulation Procedure
Original CNT
After Manipulation
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11/10/2018

25. CNT Length Determination
Length: 2.3µm
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11/10/2018

26. CNT Diameter Determination
Diameter: 10nm
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11/10/2018

27. Experimental Curve Extraction
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11/10/2018

28. Experimental and Theoretical Fit
Increasing value of shear stress
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11/10/2018

29. Shear Stress Calculation
Case 2: Length (L): 2.3µm; Diameter (D): 10nm; Aspect Ratio(A): 230, Force Applied: nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г E П / 0.05*64*A3
E = 1x1012
Dimensionless Shear Stress (Г) : 600
Calculated Frictional Shear Stress (τ ): 48.4 MPa
Dana Research Centre, NEU
11/10/2018

30. Manipulation Example on Gold
Gold Substrate
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11/10/2018

31. CNT Manipulation Dana Research Centre, NEU 11/10/2018 Original CNT
After Manipulation
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11/10/2018

32. CNT Length Determination
Length: 2.3µm
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11/10/2018

33. CNT Diameter Determination
Diameter: 28nm
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11/10/2018

34. Experimental Curve Extraction
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11/10/2018

35. Experimental and Theoretical Fit
Increasing value of Shear Stress
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11/10/2018

36. Shear Stress Calculation
Case 7: Length (L): 2.3µm; Diameter (D): 28nm; Aspect Ratio (A): 82, Force Applied: 289nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г EI П / 0.05*64*A3
E = 1x1012
Dimensionless Shear Stress : 150
Calculated Frictional Shear Stress: 267 MPa
Dana Research Centre, NEU
11/10/2018

37. CNT Manipulation Dana Research Centre, NEU 11/10/2018 Original CNT
After Manipulation
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11/10/2018

38. CNT Length Determination
Length: 3.2µm
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11/10/2018

39. CNT Diameter Determination
Diameter: 12nm
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11/10/2018

40. Experimental Curve Extraction
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11/10/2018

41. Experimental and Theoretical Fit
Increasing values of Shear Stress
Dana Research Centre, NEU
11/10/2018

42. Shear Stress Calculation
Case 8: Length (L): 3.2µm; Diameter (D): 12nm; Aspect Ratio (A): Force Applied: 489nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г E П / 0.05*64*A3
E = 1x1012
Dimensionless Shear Stress : 100
Calculated Frictional Shear Stress:5.1 MPa
Dana Research Centre, NEU
11/10/2018

43. Manipulation Example on Thiol
Thiol (Octadenathiol) on Gold Substrate
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11/10/2018

44. CNT Manipulation Dana Research Centre, NEU 11/10/2018 Original CNT
After Manipulation
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11/10/2018

45. CNT Length Determination
Length: 3.9µm
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11/10/2018

46. CNT Diameter Determination
Diameter: 5nm
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11/10/2018

47. Experimental Curve Extraction
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11/10/2018

48. Experimental and Theoretical Fit
Range of shear stress value
Median value of 75 considered
for shear stress calculation
Increasing value of shear stress
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11/10/2018

49. Shear Stress Calculation
Case 9: Length (L): 3.90µm; Diameter (D): 6nm; Aspect Ratio (A): 650, Force Applied: 719nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г E П / 0.05*64*A3
E = 1x1012
Dimensionless Shear Stress (Г) : 75
Calculated Frictional Shear Stress (τ ): 0.2 MPa
Dana Research Centre, NEU
11/10/2018

50. CNT Manipulation Dana Research Centre, NEU 11/10/2018 Original CNT
After Manipulation
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11/10/2018

51. CNT Length Determination
Length: 1.80µm
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11/10/2018

52. CNT Diameter Determination
Diameter: 23nm
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11/10/2018

53. Experimental Curve Extraction
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11/10/2018

54. Experimental and Theoretical Fit
Range of shear stress value
Median value of 85 considered
for shear stress calculation
Increasing value of shear stress
Dana Research Centre, NEU
11/10/2018

55. Shear Stress Calculation
Case 10: Length (L): 1.80µm; Diameter (D): 23nm; Aspect Ratio (A): 80.8, Force Applied: 380nN
I = Π/64 (D4)
B = 5% of D = 0.05*D
τ = Г EI / BL3 = Г E П / 0.05*64*A3
E = 1x1012
Dimensionless Shear Stress (Г ): 85
Calculated Frictional Shear Stress (τ ): 158MPa
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11/10/2018

56. Results Summary Dana Research Centre, NEU 11/10/2018
Earlier Manipulation Procedure
Our Manipulation Procedure
Sl No
Dia [nm]
Length [µm]
Aspect ratio
Point of Load app
Shear stress
(Theory)
Shear stress [Mpa]
Silicon Dioxide (SiO2) 1 12
1.2
100
0.48
450
441.7 2 10
2.3
230
0.5
600
48.4 3 16
3.9
243.7
350
23.8 4
1.6
0.45
500
490.8
Gold
7.5
4.9
653
0.49 45
0.2
8.5
2.5
294
550
21.2 28 82
150
267
3.2
266.7
5.1
Thiol 6
650 75 23
1.8
80.8 85
158
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11/10/2018

57. Discussion Dana Research Centre, NEU 11/10/2018
Wider range of Aspect Ratio Tubes yields wide range of shear stress values
Consistent point of load application, providing good opportunity for best
deformation behavior
CNT manipulation on Thiol is easy
Non uniform CNT deformation on Thiol
Partial tube movement, Cutting of tubes, Similar to CNT rolling behavior observed
Need more precise tracking of the CNT Movement along the surface, according to
the vector drawn
Precise CNT movement tracking possible only with clean surface
Vacuum manipulation and measurements a good idea
AFM Tip nature does influence manipulation results
Dana Research Centre, NEU
11/10/2018

58. Conclusion Dana Research Centre, NEU 11/10/2018
Simple Effective manipulation procedure established
Progress in obtaining better values of shear stress has been made
Theoretical Curve generation for any point of load application provides flexibility in
manipulation
Aspect ratio for CNT manipulation has been increased from
Manipulation procedure needs some improvements
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11/10/2018

59. Master Thesis Dana Research Centre, NEU Questions ??? Comments !!!
Complaints..,
Thank You
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11/10/2018