Photo-Acoustics Research Laboratory
Dynamics of Microspherical Adhesive Particles on Vibrating SubstratesÇetin Çetinkaya
Photo-Acoustics Research LaboratoryDept. of Mechanical and Aeronautical Engineering
Center for Advanced Materials ProcessingClarkson University, CAMP 241 Box 5725, Potsdam, NY 13699-5725
[email protected] (315) 268-6514 Fax: (315) 268-6695
http://clarkson.edu/mae/faculty_pages/cetinkaya.html
October 2, 2012
Seminar Abstract:
Dispersive adhesion (intermolecular Van der Waals) forces often become a dominant effect in nano- and micro-length scales as surface (e.g. electrostatic and hydrodynamic) and volume proportional (e.g. inertia) forces rapidly diminish. Decreased mechanical stiffness at these length-scales further increases the significance of adhesion. In this seminar, the focus will be on the work-of-adhesion characterization of micrometer-scale spherical particles. Following a review of the status of the theories, a non-contact characterization method will be introduced. The current method is based on the resonance frequency measurement of a spherical particle making a rocking motion on a flat surface. In the reported experiments, rocking motion is excited by a short acoustic pulse generated either by an air-coupled acoustic transducer or a contact ultrasonic transducer attached to the substrate. Elastic deformation of the particle at the contact zone and surface energy provide the required restitution force for oscillations and the angular inertia of the particle with respect to its contact point is the inertia effect. The transient response of the micro-particle is acquired with a fiber optic vibrometer, and the resonance frequency of the motion is extracted from the frequency spectrum of the acquired waveform. The resonance frequency is related to the work-of-adhesion of the particle-substrate system. The nonlinear coupling effect between modes of vibration will also be introduced. Particular applications of the presented experimental characterization approach in pharmaceutics and xerography (electrophotography) will be discussed in detail. Potential applications of the approach to biological systems and future research directions will also be discussed.
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Photo-Acoustics Research Laboratory
Dynamics of Microspherical Adhesive Particles on
Vibrating Substrates
Mechanical and Industrial EngineeringUniversity of Illinois at Chicago2:00-3:15, October 2, 2012
Çetin ÇetinkayaDept. of Mechanical and Aeronautical Engineering
Clarkson UniversityPotsdam, New York 13699-5725
[email protected] (315) 268-6514
NSF (Award #: 1066877)
Photo-Acoustics Research Laboratory
Seminar Outline• Introduction
Length-scale argument
Toner in copying/printing and pharmaceutical particles
• Adhesion models for spherical particles on flat surfaces
1-D models: JKR, DMT, etc.
2-D model: rocking motion
• Approach: Ultrasonic base and air-coupled acoustics
• Lateral pushing experiments
• Effects of nanoparticles on toner adhesion
• Nonlinear interactions between vibrational modes
• Conclusions and remarks
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Photo-Acoustics Research Laboratory
Introduction: Why Study Particle Adhesion?
• Adhesion is a significant effect, especially at nano/micro-length scales, since body (e.g. inertia) and surface forces (e.g. charge, hydrodynamic) diminish faster than adhesion.
• Micro-scale particles are involved in a wide spectrum of industrial processes and natural phenomena: Toner, pharmaceutical particles, biological cells, etc.
• Methods to make particles with narrow distributions are today available and utilized. narrow distributions increase process and end-product predictability. Near-perfect spherical particles exhibit strong adhesion.
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Photo-Acoustics Research Laboratory
Pharmaceutical Particles
• Adhesion properties of pharmaceutical particles affect:Macroscopic/bulk mechanical/adhesion propertiesPowder transfer and handlingFlowability of powdersPowder mixing/blending uniformityGranulationCompaction
• In resulting tablets, these parameters play roles in:Compaction propertiesMechanical propertiesDissolution rates/profilesContent uniformityMass density distributionPhysical stabilityMechanical integrity
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Photo-Acoustics Research Laboratory
Toner and the Xerographic Industry
Dr. Scott M. Silence, Consumables Development and Manufacturing Group Xerox Corp., June 4, 2007
Toner is a critical material for the xerographic industry: Its design impacts, energy, cost, environment, etc.
The adhesion performance of toner plays a key role in determining the image quality of the prints and copies.
Development
SN
S N
3. Toner must develop latent image on photoreceptor
Fusing
5. Toner must melt into paper
Cleaning
6. Toner must be removed from photoreceptor
Paper
Transfer4. Toner must move from photoreceptor to paper
PhotoreceptorSubstrate
Charging
Exposure
2
1
3
4
5
6
6
Photo-Acoustics Research Laboratory 7
CouplingGel
PiezoelectricTransducer
SiO2 Substrate
Output Signal
InterferometerHead
Excitation Pulse
PSLParticle
Experiment: Micro-particles on a Vibrating Substrate
Photo-Acoustics Research Laboratory
Oscillatory Dynamics of Single Particles on Surfaces
3/2
0
( , , ) 6 ( ) ( )R A
aM a W r r sin
a
Rocking (In-Plane) MotionAxial (Out-of-Plane) Motion
33/2( ) 6R A
K aF a a W K
r
θ
δe
Substrate
O′O
δe
Substrate
K. L. Johnson, K. Kendall and A.D. Roberts, Proc. R. Soc. of London. A. 324, 301 (1971).C. Dominik and A. Tielens, Philos. Mag. A 72, 783 (1995). 8
23/202
(1 ( ) )3
aa
r a
Photo-Acoustics Research Laboratory
Instrumentation Diagram of Experimental Set-up
Fiber Interferometer
Vibrometer Controller
Digitizing Oscilloscope
Video Monitor
Pulser /ReceiverUnit
Laser Probe
Transducer
Computer/ Video Card
Trigger
CCD Camera
Objective Lens
Particles
Silicon Substrate
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Photo-Acoustics Research Laboratory
Adhesion Theories: Dynamics of Particles on Surface
Linearized Axial Motion (JKR)
Natural Frequency:
Linearized Rocking Motion
Natural Frequency:*
* 2
6 ( )
( )A
On
W r r
I m r
WA is the work-of-adhesion
K is the stiffness of adhesion bondr is the mass density of the particler is the radius of the particle
WA is the work-of-adhesionr is the mass density of the particle is the mass moment of inertia of the particler is the radius of the particle
Note: It is independent of the elastic properties of the particle and substrate materials.Dominik C. and Tielens A.G.G.M., Philosophical Magazine A, 72, No.3, 783-803, 1995.
For a PSL spherical particle (D = 21.4 mm) on Si substrate, the linearized axial and rocking motion resonance frequencies are calculated:
Axial Resonance Frequency: 1.98 MHz Rocking Resonance Frequency: 38.57 kHz
1.98 MHz >> 38.57 kHz
2 21/3
3 2
327( )
20 4A
n
W K r
r
2 1 0 1 2 3 4 2
1
0
1
2
n m
PN
Hertz Model
OI
10
F
δ
Photo-Acoustics Research Laboratory
M. D. M. Peri and C. Cetinkaya, J.of Colloid and Interface Science, Vol. 288, 2005.M. D. M. Peri and C. Cetinkaya, Philosophical Magazine A, Vol. 85, No. 13, 2005.
50 52 54 56 58 60 62 64 66 68 70 72 74 76 78 80 82 84 86 88 90 92 94 96 98 1000
1
2
3
4
5
6
7
8x 10
-6
Freq (kHz)
(am
plitu
de)
Multiplication Factor (4.33)-P1 75kHz 400V
Wafer
Particle
0 50 100 150 200 250 300 350 400
-6
-4
-2
0
2
4
6
Time (sec)
Dis
pla
cem
ent(
nm
)
P1 75kHz 400V
Observation: Air-Coupled Pulse of Rocking Motion
Particle Diameter (PSL on Si) 21 mm
Air-coupled excitation (central freq): 75 kHz
Rocking frequency (approximated): 72.4 kHz
Measured rocking amplitude: θmax~ 0.06 deg
Measured rocking frequency: 76.5 kHz
Measured work-of-adhesion: 26.16 mJ/m2The first non-contact experimental demonstration of the existence of rolling resistance and its characterization.
2 (1 cos )r
Photo-Acoustics Research Laboratory 12
A
rigidrigid
W
rf
4
4512
2/3
A
neckneck
W
rf
14
4512
2/3
*2
kF k x x
r 2* / rkk
0cI k 0 5
1 5
2 16
kf
r
23 50
64
5k f r
*2
/ ( / 2) 4
( / 2)
F M D Mk
x D D
6/*kWA
Natural Frequencies and Rolling Stiffness
26 AM W r
Rolling Moment Resistance:
Lateral Pushing: Rigid Rolling:
Rocking w.r.t. the neck
Rigid Particle-Substrate
Photo-Acoustics Research Laboratory
Lateral Pushing Experiments: AFM Tip Set-up
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 500 1000 1500 2000 2500 3000 3500 4000
x (nm)
F (
nN
)
56.1
44.3
50.8
26.1
25.3
31.9
33.4
36.9
D = 31.9mm PVP particle Tipless AFM cantilever probe
W. Ding, A. Howard, M. D. M. Peri, C. Cetinkaya, Philosophical Magazine, Vol. 87, Issue 36 pp. 5685 – 5696, 2007.W. Ding, H. Zhang and C. Cetinkaya, Journal of Adhesion, Vol. 84, No. 12, pp. 996-1006, 2008.I. Akseli, M. Miraskari, H. Zhang, W. Ding, and C. Cetinkaya, Non-Contact Rolling Bond Stiffness Characterization of Polyvinylpyrrolidone (PVP) Particles, Journal of Adhesion Science and Technology (Invited), 25, 4-5, 407-434, 2011
The first work in determining the critical rolling angle
Photo-Acoustics Research Laboratory 14
• During tablet manufacturing, essential excipients associated with sticking problems are binders and lubricants. PVP’s surface adhesion characteristics affect numerous pharmaceutical unit operations such as granulation, blending, and lubrication/compaction.
• A non-toxic synthetic polymer since it is not absorbed through the gastrointestinal tract or mucous membranes.
• PVP (a typical binder) is water-soluble. It has been known for its superior ability to modify adhesion properties. Commonly used biomaterials in pharmaceutical formulations.
• Other applications: disintegrant, suspending agent, coating agent, tablet binder, and hydrophilizing biomaterial
• Particle size distribution: 20-60 µm.
Adhesion of PVP Particles
Photo-Acoustics Research Laboratory
Poly(vinyl) Pyrrolidone (PVP) Microspherical Particles
20mm
Particle mean diameter: 20mm-60mm Trench width: 4mm-10mm Trench depth: 1mm
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Photo-Acoustics Research Laboratory 16
0 20 40 60 80 100 120 140 160 180 200-8
-6
-4
-2
0
2
4
6
Time (sec)
Dis
plac
emen
t(nm
)
0 20 40 60 80 100 120 140 160 180 2000
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6x 10
-6
Freq (kHz)
Am
plitu
de (a
.u.)
Resonance Frequencies: PVP on Silicon, D = 26.4 mm
Photo-Acoustics Research Laboratory 17
0 20 40 60 80 100 120 140 160 180 2000
1
2
3
4
5
6
7x 10
-7
Freq (kHz)
Am
plitu
de (a
.u.)
0 20 40 60 80 100 120 140 160 180 200-7
-6
-5
-4
-3
-2
-1
0
1
2
3
Time (sec)
Dis
plac
emen
t(nm
)
D = 55.8 mm
Photo-Acoustics Research Laboratory 18
0 20 40 60 80 100 120 140 160 180 2000
0.5
1
1.5
2
2.5
3
3.5
4x 10
-7
Freq (kHz)
Am
plitu
de (a
.u.)
0 20 40 60 80 100 120 140 160 180 200-20
-15
-10
-5
0
5
10
15
20
Time (sec)
Dis
plac
emen
t(nm
)
D = 51.5 mm
Photo-Acoustics Research Laboratory
Resonance Frequencies of the PVP-Silicon Systems
PVP Particle D = 36.3mm PVP Particle D = 34.6mm
0 20 40 60 80 100 120 140 160 180 200-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
0.1
0.2
0.3
0.4
Time (sec)
Dis
pla
ce
me
nt(
nm
)
0 25 50 75 100 125 150 175 200 225 2500
0.3
0.6
0.9
1.2
1.5x 10
-7
Freq (kHz)
Am
plit
ud
e (
a.u
.)
Flat Substrate Trenched Substrate
3 2
1 45
4A
n
W
r
0 20 40 60 80 100 120 140 160 180 2000
0.2
0.4
0.6
0.8
1
1.2
1.4
1.6
1.8
x 10-7
Freq (kHz)
Am
plitu
de (a
.u.)
0 20 40 60 80 100 120 140 160 180-12
-10
-8
-6
-4
-2
0
2
4
6
8
Time (sec)
Dis
plac
emen
t(nm
)
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Photo-Acoustics Research Laboratory 20
Lateral Pushing Experiments
Photo-Acoustics Research Laboratory
• Adhesion measurement based on detachment is difficult
• Particle not glued to a cantilever• Detachment force is much larger
than rolling force
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W. Ding, A. Howard, M.D.M. Peri, C. Cetinkaya, Philosophical Magazine, Vol. 87, Issue 36 pp. 5685 – 5696, 2007.W. Ding, H. Zhang and C. Cetinkaya, Journal of Adhesion, Vol. 84, No. 12 , pp. 996-1006, 2008.
Lateral Pushing Experiments: SEM Test Set-up
Photo-Acoustics Research Laboratory
0
500
1000
1500
2000
2500
3000
3500
4000
4500
0 500 1000 1500 2000 2500 3000 3500 4000
x (nm)
F (
nN
)
56.1
44.3
50.8
26.1
25.3
31.9
33.4
36.9
Spherical PVP Particles: Lateral Pushing-Translating
Optical microscope image of the pushing of a 31.9mm PVP particle with a tipless AFM cantilever probe.
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Photo-Acoustics Research Laboratory
Spherical PVP Particles: Table 1, 2 and 3
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Photo-Acoustics Research Laboratory
Materials: Nano-particle Coated Toner
• Bare Polymer Particles: Nominal diameters of 9.0 µm and 6.0 µm
• Polymer particles with 24 nm diameter silica nanoparticle coating: Nominal diameter of 6.0 m, and surface area coverage of 10%, 50% and 100%
• Polymer particles with 110 nm diameter silica nanoparticle coating: Nominal diameter of 6.0 m, and surface area coverage of 50% and 100%
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Photo-Acoustics Research Laboratory
Nano-Particle Coated Toner (Side View): 0% SAC
Bare polymer particle with smooth surfaceCoated with ~ 15 nm of Au for SEM imaging Diameter: ~ 5.6 µmSubstrate: Silicon
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Photo-Acoustics Research Laboratory
Specified surface area coverage (SAC): 10%
Nanoparticle diameter: 15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Substrate: Silicon
Nano-Particle Coated Toner (Side View): 10% SAC
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Photo-Acoustics Research Laboratory
Specified SAC : 50%
Nanoparticle diameter: 15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Substrate: Silicon
Nano-Particle Coated Toner (Top View): 50%
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Photo-Acoustics Research Laboratory
Specified SAC: 50%
Nanoparticle diameter: 15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Substrate: Silicon
Nano-Particle Coated Toner (Side View): 50%
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Photo-Acoustics Research Laboratory
Specified SAC: 100%
Nanoparticle diameter: 15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Substrate: Silicon
Nano-Particle Coated Toner (Top View): 100%
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Photo-Acoustics Research Laboratory
SAC: 100%
Nanoparticle diameter: 15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Substrate: Silicon
Nano-Particle Coated Toner (Side View): 100%
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Photo-Acoustics Research Laboratory
Force-Displacement (10% SAC)
Coated Toner: Pushing Results for 10% SACSAC: 10%
Toner/Nanoparticle diameter: 6μm/15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Force-Displacement (10% SAC)
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Photo-Acoustics Research Laboratory
SAC: 50% and 100%
Toner/Nanoparticle diameter: 6μm/15~32 nm (average: ~24 nm)
Nanoparticle material: Silica
Force-Displacement (100% SAC)
Force-Displacement (50% SAC)
Coated Toner: Pushing Results for 50% and 100%
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Photo-Acoustics Research Laboratory
Nominal Diameter
(m)
Coating Nanoparticle
Size(nm)
Nanoparticle Surface Area
Coverage
Number of Particles Tested
Average Diameter
(m)
Average Pre-rolling Stiffness
(N/m)
Average Work-of-Adhesion(mJ/m2)
9.0 N/A N/A 9 9.1 1.1 0.37 0.19 20 10
6.0 N/A N/A 8 6.0 0.4 0.43 0.17 23 9.1
6.0 24 10% 11 7.3 0.6 0.75 0.68 40 36
6.0 24 10% 7 7.3 0.7 0.095 0.031 5.0 1.7
6.0 24 50% 8 6.0 0.3 0.075 0.070 4.0 3.7
6.0 24 100% 6 6.3 0.5 0.020 0.015 1.1 0.78
0% 10% 50% 100%
Substrate Substrate
Collaborators: Dr. K. Law and Dr. S. Badesha, Xerox
Summary of Work-of-Adhesion Results
Photo-Acoustics Research Laboratory
Two Possible Contact Models for Nanoparticles
Substrate Substrate
0% 10% 50% 100%
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Photo-Acoustics Research Laboratory 35
𝑀𝑅 (𝛿 , 𝜃)
�⃗�𝑠
𝜓
𝜓𝜃
𝛿(𝑡) 𝑶′
𝑩
Probe Laser Beam
PSL Particle
Substrate
Mathematical Modeling and Analysis: Nonlinear
Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis: Nonlinear
• An adhesive spherical particle with a radius of r and a mass of m on a vibrating flat surface.
• The particle undergoes out-of-plane (δ) and in-plane (θ) motions.
2( ) cos( ) ( )( ) sin( )
( ) ( , ) ( ) ( cos( ) 2 ( )
sin( ) ( )( ))
R
O R
m F m Y r X
I M m r X
Y r
The equations of motion are simplified for its free vibrational motion:
2 2
2
( )
( ( ) ) (2 ( ) ) ( , ) 0
R
O R
m F m m r
I m r m r M
A. S. Vahdat, S. Azizi and C. Cetinkaya, “Nonlinear Dynamics of Adhesive Micro-spherical Particles on Vibrating Substrates”, submitted for publication in Journal of Adhesion Science and Technology, 2012.
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Photo-Acoustics Research Laboratory
Experimental Results and Observations
60 kHz reported before as rocking resonance frequency
The response of particle is transformed into frequency domain using FFT routine in order to understand the frequency contents of the response. For some particles there was no interesting/new observation in the spectral domain:
The total depression of the top of the particle is experimentally obtained: *( ) ( ( ) ) 2 (1 cos ( ))e t t r t
Transient response of adhesive particles vibrating on a ultrasonically excited flat substrate
δe
Substrate
θ
O′O
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Photo-Acoustics Research Laboratory
Experimental Results and Observations
45.16 kHz82.70 kHz
Particle I
40.41 kHz
78.15 kHz
Substrate
θ
O′
O
In the spectral domain of depression of some particle, an interesting/new resonance frequency were observed.
Particle II
*( ) ( ( ) ) 2 (1 cos ( ))e t t r t
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Photo-Acoustics Research Laboratory
Experimental Results and Observations
36.55 kHz
64.40 kHz
• In the spectral domains of some particles a frequency doubling phenomenon is observed in the rocking resonance frequency range.
• This phenomenon cannot be explained based on previously proposed in-plane and out-of-plane motions theories.
• So a coupled dynamic of particle motion should be studied to figure out the origin of frequency doubling.
Particle III
40.86 kHz
78.56 kHz
Particle IV
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Photo-Acoustics Research Laboratory
Mathematical Modeling and analysis
2( ( ) ) (2 ( ) ) ( , ) 0O RI m r m r M
In-plane dynamics is dominated by its linear terms and its harmonic response is approximated as:
( ) sin( )rt t
Θ: Amplitude of the rocking motion
:r Rocking resonance frequency
2 2( )Rm m F m r
2 2 2 2 2 21cos ( ) 1 cos(2 )
2r r r rm r mr t m r t
Double of rocking resonance frequency
The coupling between in-plane and out-of-plane vibrations is the source of the frequency doubling.
A. S. Vahdat, S. Azizi and C. Cetinkaya, “Doubling of Rocking Resonance Frequency of an Adhesive Microparticle Vibrating on a Surface”, accepted for publication in Applied Physics Letters, 2012.
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24( )
cos ( ) 1 ( ( ) )2
tt O t
22
5OI m r
Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis
0( ) sin( ) (...)rm t t
Explanation: The cosine function doubles its argument frequency, therefore in order to see both frequencies in the spectral domain the in-plane solution has to be modified as:
Conclusion: The inclined rocking motion of particle in a three-dimensional dynamic model implies the existence of whirling-like motion of particle.
Observation: If coupling between in-plane and out-of-plane vibrations causes the frequency doubling, then why sometimes we observe the doubled frequency only?
*( ) ( ( ) ) 2 (1 cos ( ))e t t r t
This term includes the double of the rocking resonance frequency
This term includes the rocking resonance frequency
0 (...) :This non-zero term attests that the rocking motion occurs around an inclined axis with respect to the substrate normal
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24( )
cos ( ) 1 ( ( ) )2
tt O t
( ) sin( )rt t
Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis
θ0 = 3.1 mrad
θ0 = 5.1 mradθ0 = 6.5 mrad
0( ) sin( ) (...)rm t t
42
*( ) ( ( ) ) 2 (1 cos ( ))e t t r t
2( ( ) ) (2 ( ) ) ( , ) 0O RI m r m r M
2 2( )Rm m F m r
Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis
Simulation
Matching the simulations results to experimental ones to extract the work-of-adhesion and leaning angles:
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Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis
Td = 0.50 μs
Tr = 22.14 μs
*( ) ( ( ) ) 2 (1 cos ( ))e t t r t
The out-of-plane, in-plane and total depression of particles can be extracted from the simulation as:
Te-r = 22.14 μsTe-d = 0.50 μs
Te-dr = 11.07 μs
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Photo-Acoustics Research Laboratory
Mathematical Modeling and Analysis
Particle Particle Diameter
(μm)
Particle Density (kg/m3)
Approximated Leaning Angles (mrad)
Measured Work-of-Adhesion
(mJ/m2)
Expected Work-of-Adhesion
(Visser) (mJ/m2)
Particle I 21.4 1050 10.8 32.5 23.5
Particle II 21.4 1050 5.1 25.9 23.5
Particle III 21.4 1050 1.2 22 23.5
Particle IV 21.4 1050 1.0 26.5 23.5
Using experimentally obtained spectral response and simulations results, the work-of-adhesion and leaning angle values are extracted:
• No research work is available on the leaning angle approximations.
• The extracted work-of-adhesion values are in good agreement with the theoretically calculated one based on Hamaker constant.
J. Visser, Adv. Colloid Interface Sci. 3, 331 (1972).
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Photo-Acoustics Research Laboratory 46
MonolayerGraphene
PSL Particle
Si
SiO2
0.335nm
1248 nm
0.142 nm
Adhesion Energy of Monolayer Graphene on Silicon
Photo-Acoustics Research Laboratory
• A unique method is introduced and demonstrated for work-of-adhesion characterization of particles in a non-contact and lateral pushing manner.
• Lateral pushing requires contact between the particle and tip. The tip is made rough to eliminate contact-adhesion related problems.
• Non-contact method is advantageous in micro-scale adhesion characterization since particle handling/manipulation is difficult.
• Multiple frequencies in non-contact method needs to be analyzed and understood. Experiments in trenches is designed to eliminate the problems associated with multiple-rolling planes and anisotropic adhesion properties.
• Coupling between in-plane and out-plane motions can be strongly nonlinear. This is observed and reported for a number of cases here.
• Future Directions: Effects of electric charges, Graphene adhesion (effects of nano-interfaces), and particle rolling in SAW.
47
Conclusions and Remarks
Photo-Acoustics Research Laboratory
Acknowledgements
People:
Wei Ding (Professor)
M. Miraskari (Ph.D. candidate)
James Stephens (M.S. candidate)
Carson Smith (Honors student)
Ilgaz Akseli (Ph.D.)
Ivin Varghese (Ph.D.)
Christopher F. Libordi (M.S.)
Melissa E. Merrill (Undergrad R.A.)
Ganesh Subramanian (M.S.)
Liang Ban (Ph.D.)
Chen Li (Ph. D.)
Dr. Girindra N Mani (Post-doc)
Financial Support:
National Science Foundation
Xerox
Pfizer, Inc.
Wyeth Pharmaceuticals
Consortium for the Advancement of Manufacturing in Pharmaceuticals (CAMP)
OYSTAR USA
NYSERDA
Center for Advanced Materials Processing (CAMP)
Clarkson University
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