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Photo-Acoustics Research Laboratory Dynamics of Microspherical Adhesive Particles on Vibrating Substrates Çetin Çetinkaya Photo-Acoustics Research Laboratory.

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Presentation on theme: "Photo-Acoustics Research Laboratory Dynamics of Microspherical Adhesive Particles on Vibrating Substrates Çetin Çetinkaya Photo-Acoustics Research Laboratory."— Presentation transcript:

1 Photo-Acoustics Research Laboratory Dynamics of Microspherical Adhesive Particles on Vibrating Substrates Çetin Çetinkaya Photo-Acoustics Research Laboratory Dept. of Mechanical and Aeronautical Engineering Center for Advanced Materials Processing Clarkson University, CAMP 241 Box 5725, Potsdam, NY 13699-5725 cetin@clarkson.educetin@clarkson.edu (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. 1

2 Photo-Acoustics Research Laboratory Dynamics of Microspherical Adhesive Particles on Vibrating Substrates Mechanical and Industrial Engineering University of Illinois at Chicago 2:00-3:15, October 2, 2012 Çetin Çetinkaya Dept. of Mechanical and Aeronautical Engineering Clarkson University Potsdam, New York 13699-5725 cetin@clarkson.edu (315) 268-6514 NSF (Award #: 1066877)

3 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 3

4 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. 4

5 Photo-Acoustics Research Laboratory Pharmaceutical Particles Adhesion properties of pharmaceutical particles affect: Macroscopic/bulk mechanical/adhesion properties Powder transfer and handling Flowability of powders Powder mixing/blending uniformity Granulation Compaction In resulting tablets, these parameters play roles in: Compaction properties Mechanical properties Dissolution rates/profiles Content uniformity Mass density distribution Physical stability Mechanical integrity 5

6 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 S N SN 3. Toner must develop latent image on photoreceptor Fusing 5. Toner must melt into paper Cleaning 6. Toner must be removed from photoreceptor Paper Transfer 4. Toner must move from photoreceptor to paper Photoreceptor Substrate Charging Exposure 2 1 3 4 5 6 6

7 Photo-Acoustics Research Laboratory 7 Coupling Gel Piezoelectric Transducer SiO 2 Substrate Output Signal Interferometer Head Excitation Pulse PSL Particle Experiment: Micro-particles on a Vibrating Substrate

8 Photo-Acoustics Research Laboratory Oscillatory Dynamics of Single Particles on Surfaces Rocking (In-Plane) MotionAxial (Out-of-Plane) Motion θ δe δe Substrate O′ O δeδe 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

9 Photo-Acoustics Research Laboratory Instrumentation Diagram of Experimental Set-up Fiber Interferometer Vibrometer Controller Digitizing Oscilloscope Video Monitor Pulser /Receiver Unit Laser Probe Transducer Computer/ Video Card Trigger CCD Camera Objective Lens Particles Silicon Substrate 9

10 Photo-Acoustics Research Laboratory Adhesion Theories: Dynamics of Particles on Surface Linearized Axial Motion (JKR) Natural Frequency: Linearized Rocking Motion Natural Frequency: W A is the work-of-adhesion K is the stiffness of adhesion bond r is the mass density of the particle r is the radius of the particle W A is the work-of-adhesion  is the mass density of the particle is the mass moment of inertia of the particle r 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 Hertz Model 10 F δ

11 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. Observation: Air-Coupled Pulse of Rocking Motion Particle Diameter (PSL on Si)21  m Air-coupled excitation (central freq):75 kHz Rocking frequency (approximated):72.4 kHz Measured rocking amplitude:θ max ~ 0.06 deg Measured rocking frequency: 76.5 kHz Measured work-of-adhesion: 26.16 mJ/m 2 The first non-contact experimental demonstration of the existence of rolling resistance and its characterization.

12 Photo-Acoustics Research Laboratory 12 Natural Frequencies and Rolling Stiffness Rolling Moment Resistance: Lateral Pushing: Rigid Rolling: Rocking w.r.t. the neck Rigid Particle-Substrate

13 Photo-Acoustics Research Laboratory Lateral Pushing Experiments: AFM Tip Set-up D = 31.9  m 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

14 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

15 Photo-Acoustics Research Laboratory Poly(vinyl) Pyrrolidone (PVP) Microspherical Particles  m Particle mean diameter: 20m-60m Trench width: 4m-10m Trench depth: 1m 15

16 Photo-Acoustics Research Laboratory 16 Resonance Frequencies: PVP on Silicon, D = 26.4  m

17 Photo-Acoustics Research Laboratory 17 D = 55.8  m

18 Photo-Acoustics Research Laboratory 18 D = 51.5  m

19 Photo-Acoustics Research Laboratory Resonance Frequencies of the PVP-Silicon Systems PVP Particle D = 36.3  mPVP Particle D = 34.6  m Flat Substrate Trenched Substrate 19

20 Photo-Acoustics Research Laboratory 20 Lateral Pushing Experiments

21 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 21 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

22 Photo-Acoustics Research Laboratory Spherical PVP Particles: Lateral Pushing-Translating Optical microscope image of the pushing of a 31.9mm PVP particle with a tipless AFM cantilever probe. 22

23 Photo-Acoustics Research Laboratory Spherical PVP Particles: Table 1, 2 and 3 23

24 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% 24

25 Photo-Acoustics Research Laboratory Nano-Particle Coated Toner (Side View): 0% SAC Bare polymer particle with smooth surface Coated with ~ 15 nm of Au for SEM imaging Diameter: ~ 5.6 µm Substrate: Silicon 25

26 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 26

27 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% 27

28 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% 28

29 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% 29

30 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% 30

31 Photo-Acoustics Research Laboratory Force-Displacement (10% SAC) Coated Toner: Pushing Results for 10% SAC SAC: 10% Toner/Nanoparticle diameter: 6μm/15~32 nm (average: ~24 nm) Nanoparticle material: Silica Force-Displacement (10% SAC) 31

32 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% 32

33 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/m 2 ) 9.0N/A 9 9.1  1.10.37  0.1920  10 6.0N/A 8 6.0  0.40.43  0.1723  9.1 6.02410%11 7.3  0.60.75  0.6840  36 6.02410%7 7.3  0.70.095  0.0315.0  1.7 6.02450%8 6.0  0.30.075  0.0704.0  3.7 6.024100%66.3  0.50.020  0.0151.1  0.78 0% 10% 50% 100% Substrate Collaborators: Dr. K. Law and Dr. S. Badesha, Xerox Summary of Work-of-Adhesion Results

34 Photo-Acoustics Research Laboratory Two Possible Contact Models for Nanoparticles Substrate 0% 10% 50% 100% 34

35 Photo-Acoustics Research Laboratory 35 Probe Laser Beam PSL Particle Substrate Mathematical Modeling and Analysis: Nonlinear

36 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. The equations of motion are simplified for its free vibrational motion: 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. 36

37 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: Transient response of adhesive particles vibrating on a ultrasonically excited flat substrate δeδe Substrate θ O′ O 37

38 Photo-Acoustics Research Laboratory Experimental Results and Observations 45.16 kHz 82.70 kHz Particle I 40.41 kHz 78.15 kHz Substrate θ O′O′ O In the spectral domain of depression of some particle, an interesting/new resonance frequency were observed. Particle II 38

39 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 39

40 Photo-Acoustics Research Laboratory Mathematical Modeling and analysis In-plane dynamics is dominated by its linear terms and its harmonic response is approximated as: Θ : Amplitude of the rocking motion Rocking resonance frequency 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. 40

41 Photo-Acoustics Research Laboratory Mathematical Modeling and Analysis 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? This term includes the double of the rocking resonance frequency This term includes the rocking resonance frequency :This non-zero term attests that the rocking motion occurs around an inclined axis with respect to the substrate normal 41

42 Photo-Acoustics Research Laboratory Mathematical Modeling and Analysis θ 0 = 3.1 mrad θ 0 = 5.1 mrad θ0 = 6.5 mrad 42

43 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: 43

44 Photo-Acoustics Research Laboratory Mathematical Modeling and Analysis T d = 0.50 μs T r = 22.14 μs The out-of-plane, in-plane and total depression of particles can be extracted from the simulation as: T e-r = 22.14 μs T e-d = 0.50 μs T e-dr = 11.07 μs 44

45 Photo-Acoustics Research Laboratory Mathematical Modeling and Analysis ParticleParticle Diameter (μm) Particle Density (kg/m 3 ) Approximated Leaning Angles (mrad) Measured Work-of-Adhesion (mJ/m 2 ) Expected Work-of-Adhesion (Visser) (mJ/m 2 ) Particle I21.4105010.832.523.5 Particle II21.410505.125.923.5 Particle III21.410501.22223.5 Particle IV21.410501.026.523.5 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). 45

46 Photo-Acoustics Research Laboratory 46 MonolayerGr aphene PSL Particle Si SiO 2 0.335nm 1248 nm 0.142 nm Adhesion Energy of Monolayer Graphene on Silicon

47 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

48 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 48


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