Nanotechnology Research at the School of Mechanical Engineering, Purdue University
Nanotechnology is understanding and control of matter at dimensions of roughly 1 to 100 nanometers (a nanometer is one-billionth of a meter; a sheet of paper is about 100,000 nanometers thick), where unique phenomena enable novel applications. Encompassing nanoscale science, engineering and technology, nanotechnology involves imaging, measuring, modeling, manufacturing, and manipulating matter at this length scale.
At the nanoscale, the physical, chemical, and biological properties of materials differ in fundamental and valuable ways from the properties of individual atoms and molecules or bulk matter. Nanotechnology research is directed toward understanding and creating improved materials, devices, and systems that exploit these new properties.
Nanotechnology is a dynamic and expanding research area in the School of Mechanical Engineering, Purdue University. The research activities are built upon traditional mechanical engineering disciplines, but extended into the nanoscale science and technology with the use of modern experimental and computational tools. Current research activities include nanoscale heat transfer, fluidics, manufacturing, optics, nano- and mciro-scale electro-mechanical devices (NEMS and MEMS), with Most of the research is conducted at the newly established Birck Nanotechnology Center. A number of research laboratories provide state-of-the-art facilities for Nanotechnology research projects:
MEMS and Nanotechnology have enabled label-free and scalable detection of biologically significant molecules such as DNA, RNA, proteins and small molecules whose detection in small quantities is of paramount importance for early disease diagnostics. Current research areas include 1) development of nanomechanical and optical biosensors and their application to detection of a variety of proteins including cancer markers 2) novel receptor molecules and their integration into biosensing, 3) biosensing using nanoparticles, 4) rapid detection of pathogens and 5) sensitivity enhancement of biosensors. The work is currently supported by NSF and NASA.
Micro- and Nano- Fluidics
Research in the microfluidics laboratory is concentrated in two primary areas: experimental fluid dynamics in micro/nano domains and microfabricating novel microfluidic devices. Ongoing projects include fundamental biology (response of live cells to flow stresses, below right), fundamental fluid mechanics (characterizing microscopic supersonic flows, below left; nanoparticle flow dynamics), and characterizing biolomedical microdevices (below center). Currently the Microfluidics laboratory is supported by the NSF (Ocean Biology and Nanoscale Science and Engineering), DOD (Crane-NSWC), the State of Indiana, and industry.
Numerical simulation plays a critical role in exploring novel nanoscale structures, materials, devices and systems. Research in this area is focused on the development of physical models and computational methodologies to address a number of areas including emerging micro- and nanoelectronics, phase-change memory technologies, ultra-fast laser manufacturing, as well as the fundamentals of nanoscale thermal and fluid transport. Computational techniques include novel finite volume techniques for the phonon Boltzmann transport equation, molecular dynamics techniques, as well as multiscale methods spanning micro, meso and macro scales. Research in this area is supported by NSF, the state of Indiana and the electronics industry.
Turning the promise of nanoscience into new technologies is one of the biggest challenges that face the research community today. The bottleneck is the lack of technologies for manufacturing nanostructures and nanomaterials in large quantity and at low cost. Research in nano-manufacturing is focused on developing optical based, low cost, massively parallel manufacturing techniques. Specifically, a type of nanostructure, called nanoscale optical antenna is developed to concentrate energy of light into a nanoscale domain, and is being used for nanomanufacturing purpose. This program involves researches in several disciplines, including manufacturing science and engineering, control, radiation, optics, and mechanics. It is currently supported by NSF, ONR, and NASA.
Nanoscale Thermal-Electrical Transport
The interplay between thermal and electrical energy at small scales can strongly influence the functional behavior of many types of devices such as direct energy conversion elements, heat sinks, and field-effect transistors. Research at the Nanoscale Thermo-Fluids Lab seeks to address these issues by studying novel nanomaterials, particularly carbon nanotubes, both from the perspective of material synthesis and characterization and from the perspective of functional engineering performance. The laboratory’s activities include detailed experimental and computational studies synthesis by plasma-enhanced chemical vapor deposition with applications to single-wall carbon nanotubes transistors, and multi-wall carbon nanotubes arrays used to enhance thermal/electrical interface conductance, boiling heat transfer, and biosensor performance. Further, the lab has developed unique capabilities to measure and model thermal-electrical energy transport and conversion from nanoscale electron emitters. Researchers in the laboratory routinely collaborate with electrical engineers, material scientists, physicists, chemists, and biologists, and the work is supported by NSF, NASA, the Air Force Research Laboratory, the Semiconductor Research Corporation, and a variety of industrial interests.
Thermal transport is becoming increasingly critical in the design and performance of micro-and nano-systems. Research in this area includes the development of a range of micropumping approaches and high-resolution measurement techniques. Representative projects include the development of a micromechanical electrohydrodynamics (MEHD) based liquid pump with multiple driving mechanisms to deliver high flow rates, and an ionic wind-driven heat transfer enhancement scheme. Other areas of research include microscale actuation of liquids using electrowetting and dielectrophoresis, thin film evaporation, single and two-phase microchannel transport and development of carbon nanotube-based heat spreaders. Research outcomes from these efforts have direct applications in providing solutions for the thermal management of microelectronics, and are supported by NSF and the State of Indiana, besides a wide range of industrial sponsors.
Nano Thermo-Physical Engineering
The behavior of any physical system can be related to atomic-scale description. With an atomic-level knowledge of the energy carrier (photon, electron, phonon, and fluid particle) characteristics and behaviors, one is able to move up to design nano- and micro-structures with the desired size effects, or to synthesize new materials with the desired functions. Research at the Nano Thermo-Physical Engineering Lab seeks to build and expand the understanding of the fundamentals of atomic-level carrier transport and interactions, and to apply this knowledge to important energy and information technologies. Current projects include the engineering of electron-phonon coupling in quantum dot solar cells, enhanced laser cooling of semiconductors and ion-doped solids, controlled thermal emission using modulated micro- and nano-structures, thermo-optical management of nano-lasers, etc.
Advanced Micro/Nanomechanical Materials and Process Technologies
To date, materials selection capability in micro/nanosystems applications has been relatively limited, due primarily to the predominance of microfabrication processes and infrastructure dedicated to silicon. While silicon has proven to be an excellent material for many applications, no one material can meet the needs of all applications. Research in this area, therefore, seeks to develop the materials and process technologies required for realization of applications that are either impractical or impossible using conventional silicon-based micromachining, e.g. biomedical and harsh environment applications. Areas of specific interest with this context that are currently under development include anisotropic titanium micromachining, micromechanical composites, and novel applications thereof.
- The creation of new materials with superior strength, electrical conductivity, conduction or resistance to heat and other properties.
- Microscopic machines for a variety of uses, including probes that could be injected into the body for medical diagnostics and repair.
- A technology in which biology and electronics are merged, creating “bio-chips” that detect food-borne contamination, dangerous substances in the blood or chemical warfare agents in the air.
- The creation of artificial organs and prosthetics that enhance the quality of life.