Mechanical & Industrial Engineering - Materials & NanoTechnology

Kenneth Brezinsky Kenbrez@uic.edu

Problem Statement and Motivation In order to improve internal combustion engine fuel efficiency and mitigate the emission of harmful pollutants, there is a need for predictive chemical and physical models that can predict the behavior of real fuels from the fuel tank to the exhaust.

Chemical details of how fuels burn determine their • Burning efficiency: i.e. energy saving, • Cleanness : i.e. soot, NOx, particulates, priority pollutants • Applications: i.e. aviation, spark ignited, or diesel engines; stationary power plants

Single Pulse High Pressure Shock tube Lower Pressure Single Pulse Shock Tube

Future, alternative, fuels will have different chemical burning characteristics; • Combustion chemistry information is necessary of future application

Funding sources: NSF, AFOSR, DOE, NASA, DOD

Technical Approach Develop a chemical experimental and kinetic modeling validation database at real combustor conditions.

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Experiments conducted in two different shock tubes 1) Very high pressure tube: 15-1000 bar 2) Lower pressure tube: 1 -10 bar Chemical species obtained as a function of temperature (6002500K) for a given pressure and time (1- 3 msec) • Species concentrations simulated with detailed chemical models developed in our laboratory

Key Achievements and Future Goals Representative Publications: • “Experimental and modeling study on the pyrolysis and oxidation of n-decane and n-dodecane”, Proc. Combust. Inst., 34, 361-368, 2013. (T. Malewicki, K. Brezinsky) • “Experimental and modeling study on the oxidation of Jet A and the n-dodecane/iso-octane/n-propylbenzene/1,3,5trimethylbenzene surrogate fuel “, Comb. Flame, 160(1), 1730, 2013 (T. Malewicki, S. Gudiyella and K. Brezinsky).

• “Pyrolysis of n-Heptane and Oxidation in Mixtures of Ethylene/Methane and iso-Octane” , J. Prop. Power 29, 732743, 2013 (A. Fridlyand, A. Mandelbaum and K. Brezinsky).

Carmen M. Lilley, Mechanical Engineering Primary Grant Support: NSF

Problem Statement and Motivation

FIG. 1: (a) Micrograph of a Ag nanowire under 4-probe I-V measurement, (b) STM scan of the cross-section from left-to-right, (c) line scan profile of cross-section from left-to-right (solid curve) and right-to-left (dashed curve).

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Successful integration of nanosystems into microelectronics depends on stable material properties that are reliable for at least a 10 year lifecycle with over a trillion cycles of operation.

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Fundamental understanding of the physics of deformation and failure in nanometer scale capped or layered structures, where surfaces play a dominant role, does not exist. Prior work has mostly focused on monolithic nanometer scale materials.

FIG. 2: Electromigration of a Cu nanowire with the current stress of 4.2 mA (length = 2.04 µm, width = 90 nm, and thickness = 50nm): (a) 0 min, (b) 40 min, (c) 80 min, (d) 120 min, and (e) 137.5 min.

Key Achievements and Future Goals

Technical Approach •

Identify surface contaminants present in as-synthesized nanowires according to metallic, organic, and mixed-materials classifications.

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Measure the electrical properties of as-synthesized nanowires and identify contamination effects on electrical properties with an accuracy of 5%.

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Measure the stability of electrical properties of nanowires under accelerated electrical testing and classified according to structure.

[1] [2] [3] [4]

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Preliminary results on measuring the presence of surface contaminants and their influence on electrical properties completed [1].

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In depth study on size and surface effects on electromigration for Cu and Au nanowires have been performed [2-4]

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Additionally, this work has been extended to studying electron surface scattering for single crystalline Ag nanowires.

C. M. Lilley, Q. J. Huang, Applied Physics Letters 2006, 89, 203114.

Q. J. Huang, C. M. Lilley, M. Bode, R. Divan, Journal of Applied Physics 2008, 104, 23709.

Q. Huang, C. M. Lilley, R. Divan, Nanotechnology 2009, 20, 075706.

Q. Huang, C. M. Lilley, R. S. Divan, M. Bode, IEEE Transactions in Nanotechnology 2008, 7, 688.]

A. Salehi-Khojin, Mechanical and Industrial Engineering

Problem Statement and Motivation • To perform a fundamental understanding of chemical sensing in graphene-based chemical field effect transistors for the development of next generation chemical sensors.

• To examine the sensing performance of external defects on insulating substrate and internal defects on graphene surface.

• To study the effect of humidity and different dopant on the sensitivity of graphene sensors.

Technical Approach • Device fabrication, characterizations and sensing experiments under different conditions • Density Functional Theory calculations to explore the sensing mechanism in graphene

• Suspended graphene fabrication to deconvolute the role of external defects on substrate B. Kumar, K. Min, M. Bashirzadeh, A. Barati-Farimani, M.-H. Bae, D. Estrada, , Y. D. Kim, P. Yasaei, Y. D. Park, E. Pop, N. R. Aluru, A. Salehi-Khojin, The Role of External Defects in Chemical Sensing of Graphene Field-Effect Transistors, NanoLetters, 3 (5), 1962–1968, 2013.

Key Achievements and Future Goals

Suresh K. Aggarwal, Mechanical and Industrial Engineering

Problem Statement and Motivation •

Use of Monte Carlo and Molecular Dynamics methods to investigate thermodynamics and flow processes at nanoscales

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Dynamics of droplet collision and interfacial processes

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Interaction of a nanodroplet with carbon nanotube

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Solid-liquid Interactions and Nanolubrication

Vaporization of a non-spherical nano-droplet

Key Achievements and Future Goals

Technical Approach Z

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Molecular Dynamics Simulation of Droplet Evaporation, Int. J. of Heat & Mass Transfer, 46, pp. 3179-3188, 2003.

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Molecular Dynamics Simulations of Droplet Collision. M.S. Thesis, K. Shukla, 2003.

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MD simulation of the collision between two nano-droplets

Carmen M. Lilley, Mechanical Engineering (a)

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Problem Statement and Motivation

Undeformed NW centerline

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Deformed NW centerline

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Surface effects, such as a surface elastic modulus and surface stress have been predicted for FCC NWs from atomistic simulations.

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Experimentally, elastic modulus measurements of FCC metal NWs have been found to vary widely. Some results indicate apparent size effects, other studies indicate no size effects.

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For Nanoelectromechanical Systems (NEMS), accurate elastic properties are necessary to design devices.

p(x)=Hv'' (b)

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Modeling Surface Stress Effects on the Static Bending Behavior of Nanowires (NW). (a) Schematic of the undeformed and deformed NW centerline. (b) Crosssectional view of a rectangular NW with the surface highlighted. (c) Crosssectional view of circular NW with the surface highlighted..

Key Achievements and Future Goals

Technical Approach •

Model the elastic bending behavior of face centered cubic (FCC) metals with continuum mechanics.

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Derived analytical solutions for NWs under static and dynamic bending. [1,2]

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Apply Young-Laplace Theory to study transverse load effects as a result of surface stress of nanowires (NWs) due to undercoordinated atoms at the surface.

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Validated theory that surface stress and boundary conditions affect the apparent elastic modulus measured experimentally. [1,2]

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Study the influence of boundary conditions on the resultant bending mechanical behavior of nanowires.

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Proposed a surface effect factor as a qualitative parameter predict the influence of surface stress and geometry on the elastic behavior of static bending nanowires. [1,2]

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Test hypothesis that surface stress and boundary conditions affect the apparent elastic modulus of NWs.

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Extending the method to large deformation of nanowires for application to NEMS resonators. [3]

[1] J. He, C. M. Lilley, Nano Letters 2008, 8, 1798.

[2] J. He, C. M. Lilley, Applied Physics Letters 2008, 93, 263108.

[3] J. He, C. M. Lilley, Computational Mechanics In Press.

Farzad Mashayek, MIE/UIC; Themis Matsoukas, ChE/Penn State Primary Grant Support: NSF

Problem Statement and Motivation

Simulated flow of ions over a nanoparticle

Nanoparticles of various materials are building blocks and important constituents of ceramics and metal composites, pharmaceutical and food products, energy related products such as solid fuels and batteries, and electronics related products. The ability to manipulate the surface properties of nanoparticles through deposition of one or more materials can greatly enhance their applicability.

Nanolayer coating on a silica particle

Key Achievements and Future Goals

Technical Approach A low-pressure, non-equilibrium plasma process is developed using experimental and computational approaches. Two types of reactors are being considered. The first reactor operates in “batch” mode by trapping the nanoparticles in the plasma sheath. Agglomeration of the particles is prevented due to the negative charges on the particles.

The second reactor is being designed to operate in a “continuous” mode where the rate of production may be significantly increased.

This reactor will also provide a more uniform coating by keeping the nanoparticles outside the plasma sheath.

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The batch reactor is already operational and has been used to demonstrate the possibility of coating nanoparticles.

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A reaction model has been developed to predict the deposition rate on the nanoparticle surface.

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The possibility of using an external magnetic field to control the trapping of the particles has been investigated computationally.

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The experimental effort is now focused on the design of the “continuous” mode reactor.

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The computational effort is focused on development of a comprehensive code for simulation of the plasma reactor, nanoparticle dynamics, and surface deposition.

C. M. Megaridis, A. Yarin, Mechanical and Industrial Eng., UIC; Y. Gogotsi, J.C. Bradley, Drexel Univ.; H. Bau, Univ. Pennsylvania Primary Grant Support: National Science Foundation

Problem Statement and Motivation •

Investigate the physical and chemical properties of aqueous fluids contained in multiwall carbon nanotubes

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Determine the continuum limit for fluid behavior under extreme confinement

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Provide experimental data for parallel modeling efforts

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Evaluate the feasibility of fabricating devices using carbon nanotubes as building blocks

Key Achievements and Future Goals

Technical Approach •

Multiwall carbon nanotubes filled by high-pressure high-temperature processing in autoclaves

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Gas/Liquid interfaces in carbon nanotubes with diameter above 10nm resemble interfaces in macroscopic capillaries

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Nanotube diameter in the range 5nm-200nm, and lengths 500nm10μm

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Non-continuum behavior observed in nanotubes with diameter below 10nm

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Gas/liquid interfaces used as markers of fluid transport

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Wettability of carbon walls by water observed; important property for adsorption applications

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High-resolution electron microscopy and chemical analysis techniques used to resolve behavior of fluids stimulated thermally in the electron microscope

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Future applications include drug delivery systems, lab-on-a-chip manufacturing, electrochemical cells, etc.

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Model simulations used to interpret experimental observations

C. M. Megaridis, Mechanical and Industrial Engineering; C. Takoudis, Bioengineering; J. Belot, Univ. Nebraska-Lincoln; J. McAndrew, Air Liquide, Inc. Primary Grant Support: Air Liquide

Problem Statement and Motivation •

Patterned metal films are essential to a wide range of applications ranging from printed circuits, to thin-film displays and electrodes in biomedical implants

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Inkjet printing has environmental benefits while offering flexibility, cost savings, and scalability to large area substrates

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Initial focus on Copper due to its very low resistivity. Future extension to bio-compatible metals

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Homogeneous metal inks eliminate obstacles encountered while using nanoparticle ink suspensions

Key Achievements and Future Goals

Technical Approach •

Synthesis of metal compounds as primary ingredients of homogeneous inks

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Ink physical and rheological properties (viscosity, surface tension) optimized for printability

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Printing tests for optimal line formation; thermal treatment to reduce the deposit to pure metal; final product testing/evaluation

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X-ray photoelectron spectroscopy and electron microscopy used to characterize deposit chemical composition and surface quality

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Candidate organocopper compounds and solvents have been identified, providing facile decomposition to metallic copper (removal of ligands + reduction of Cu2+ to Cu0), and copper content > 10% wt.

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Copper lines printed in the laboratory indicate that homogeneous solutions of organocopper compounds can be developed with suitable properties for ink-jet printing

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Research has the potential to catapult progress in metal ink fabrication and in-situ formation of metallic lines with feature size in the 10-100 m range

Laxman Saggere, Mechanical and Industrial Engineering Primary Grant Support: NSF

Problem Statement and Motivation A 20-m sphere gripped & moved by two fingers SEM of the micromanipulator chip Integrated micromanipulator system

A 20-m sphere rotated between two fingers

A micro-object gripped & moved by the fingers

Motivation: Nanomanufacturing is critical for building new functional and useful products. Nanomanufacturing by an assembly-based approach promises to fill the void between the current “bottom-up” and “top-down” approaches and enable assembly of building blocks in future NEMS. However, despite recent advances, currently available tools and techniques for mechanical manipulation of micro/nano-scale objects lack dexterity to accomplish complex assembly of nano-scale objects. The success of assembly-based nanomanufacturing will depend on a micromanipulator tool with high-degree of dexterity beyond that provided by current simple cantilevers and parallel jaw grippers and tweezers.

Objectives: To investigate the principles and fundamental issues in a novel manipulation methodology based on the coordinated action of multiple agile fingers at a chipscale to accomplish controlled contact manipulation tasks such as grasp, rotate, regrasp, move and position micro- and nano-scale objects in a defined 2D workspace.

Experimental setup including user control inputs and visual feedback A micro-object rotated between two fingers

Technical Approach The approach involves a novel chipscale micromanipulator comprised of four (or more) tiny compliant fingers, each of which can be independently actuated by integrated piezo actuators. By providing controlled actuation, the fingers can be guided to move in-plane and coordinate with each other to carry out controlled manipulation tasks such as grasp, rotate, move point-to-point and position micro- and nano-scale objects and perform assembly operations in a defined 2D workspace in the plane of the chip. The actuation, and thus, the motion of the micromanipulator fingers can be controlled by means of external user inputs via a gaming controller or a programmed software and visual feedback of locations and motions of the fingers/objects on a video monitor.

Key Achievements and Future Goals Key Achievements: A novel micromanipulation system comprised of a multifingered micromanipulator chip integrated with piezo actuators and enclosed in a precision-machined custom housing has been developed.

This micromanipulator system enables highly dexterous manipulations of micro-scale objects on the chip by coordinated action of the fingers when controlled in a close-loop by external user inputs supplied via a wireless gamming controller.

Future Goals: To achieve high precision coordinated manipulation of micro/nano-scale objects incorporating a more sophisticated position/force feedback and a fully programmed motion planning for assembly of the objects in the manipulator workspace.

S. Sinha-Ray, Y. Zhang, Prof. A.L. Yarin (MIE, UIC)

Problem Statement and Motivation •

Development of a novel method of solution blowing of monolithic and core-shell nanofibers.

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Incorporation of such by-products of BioDiesel production as soy protein into solution blown nanofibers.

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Demonstration of robust nanofiber nonwovens containing soy protein.

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Carbonization of core-shell polymer nanofibers and transforming them into amorphous carbon nanotubes.

Key Achievements and Future Goals

Technical Approach •

Solution blowing with gas speeds of about 230-270 m/s.

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Solutions of soy protein and Nylon-6 in formic acid.

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Collection of nanofibers on rotating drums.

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Carbonization to make carbon nanotubes.

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SEM, staining and fluorescence imaging.

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To appear in Biomacromolecules (in press, 2011)

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Demonstration that solution blowing can produce nanofibers at a high rate.

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Formation of carbon nanotubes from core-shell nanofibers.

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Formation of robust nanofiber nonwovens containing about 40% of soy protein.

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Future work will explore strength of soy protein nonwovens; nanofibers will be decorated with silver nanoparticles for applications in catalysis.

S. Sinha-Ray, Y. Zhang, Prof. A.L. Yarin (MIE, UIC)

Problem Statement and Motivation •

Nano-textured surfaces for the enhanced spray cooling, especially for microelectronics, avionics and space applications.

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Drop cooling with local heat removal rates of about 1 kW/sq.cm.

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Electrokinetic delivery of coolant to nano-textured surfaces (joint with IIT).

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Suppression of drop receding and bouncing.

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Significant surface area enhancement.

Key Achievements and Future Goals

Technical Approach •

Electrospinning of polymer (PAN) nanofiber mats onto a wafer.

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Sputter coating with Pt-Pd to a thickness of 15 nm.

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Metal-plating onto nanofibers with control of grain sizes.

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Drop impact: water and Fluorinerts.

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SEM and CCD Camera imaging.

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Published in Langmuir 27, 215-226 (2011) and Physical Review E v. 83, 036305 (2011)

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Contact line of a fully spread-out drop is pinned, practically no splashing, receding and bouncing.

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The physical mechanism of pinning and millipede-like drop structure is kindred to the shaped-charge (Munroe) jets.

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Local heat removal rates of the of about 0.7 kW/sq.cm have been demonstrated with water.

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Future work will explore pinning of drops at substrates at temperatures of 200-300 C, detail impacts of Fluorinerts and measure heat removal rates for them.