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Dept. Micro-Nano Mechanical Science and Engineering, Nagoya University, JAPAN

 

TOPICS

  • Presentations will be made at The 6th World Tribology Congress (Beijing, China).
    Effect of fatty acid additives on viscoelastic properties of poly-alfa-olefin lubricants confined and sheared in nanometer-sized gap
      by Shintaro ITOH, Kento KAMIYA, Kenji FUKUZAWA, Hedong ZHANG
    Simultaneous in situ measurements of contact state and friction to understand the mechanism of lubrication with nanometer-thick liquid lubricant films
      by Hedong ZHANG, Yasunaga MITSUYA, Yusuke TAKEUCHI, Kenji FUKUZAWA, Shintaro ITOH
    Temperature dependency of shear properties of nanometer-thick liquid lubricant films: a molecular dynamics study
      by Takayuki KOBAYASHI, Hedong ZHANG, Kenji FUKUZAWA, Shintaro ITOH
    Measurement of shape of nm-sliding gaps by using ellipsometric microscopy
      by Kenji FUKUZAWA, Yusuke SASAO, Shintaro ITOH, Hedong ZHANG
  • Presentations will be made at INTERMAG Europe 2017 (Dublin,Ireland) .
    Real-time Observation of Molecularly Thin Lubricant Films on Head Sliders Using Rotating-Compensator-Based Ellipsometric Microscopy
      by Kenji Fukuzawa,Ken Miyata, Chihiro Yamashita, Shintaro Itoh, Hedong Zhang
  • Presentations will be made at MNC 2016 (29th International Microprocesses and Nanotechnology Conference, Kyoto, Japan).
    Viscoelasticity of a Photoresist Used for Nanoimprint Lithography Measured Under Confinement in Nanometer-sized Gaps
    by S. Itoh, K. Takahashi, K. Fukuzawa, H. Zhang (10D-6-5, 2016/11/10)
    Reduction of Analysis Time in the Size Separation of Large DNA Using Size Exclusion Chromatography-based Electrophoresis Microchip Driven by Pulsed Electric Field
    by N. Azuma, S. Itoh, K. Fukuzawa, H. Zhang (11P-11-84, 2016/11/11)
  • Presentations will be made at Tribology Frontiers Conference(Chicago, USA).
    Effect of Molecular Chemical Structures on Shear Properties of Nanometer-Thick Liquid Lubricant Films: A Coarse-Grained Molecular Dynamic Study
    by T. Kobayasshi, H. Zhnag, K. Fukuzawa, S. Itoh (2016/11/13)
    Temperature Dependence of Viscosity of Poly-Alpha-Olefins Sheared in a Nanometer-size Gap
    by S. Itoh, Y. Ota,K. Fukuzawa, H. Zhang (2016/11/13)
  • Takayuki Kobayashi(D1 student) recieved JSME Fellow Award CONGRATULATIONS!

Overview

With the progress of micro/nano technology, drastic increase in performance has been attempt by controlling mechanical elements on the micro/nano-meter scale, for example, in the designs for automobiles, micro/nano electromechanical system (MEMS/NEMS) and hard disk drives (HDDs). Engineering related to lubrication and control of friction of mechanical elements is called tribology. In the advanced mechanical system design, tribology, especially micro/nanotribology (tribology on the micro/nano scale), has become increasingly important. For example, the friction of the mechanical elements significantly affects the fuel economy of automobiles, and the friction is caused by the phenomena on the nano-scale between the mechanical element surfaces. Therefore, a monolayer-thick organic film gives substantial influences on the friction. In HDDs, the technology of flying of a read/write head at 1-nm high on the rotating disk can improve information recording density. In such micro-world, the movement of machines is governed by intermolecular forces; therefore, establishing a new discipline expanding beyond conventional tribology for macro machines has been required.
In our laboratory, we are aiming at drastic improvement of the friction and lubrication performance of the advanced mechanical systems by controlling the nanoscale properties. Furthermore, we are attempting establishment of nanotribology as a new discipline of tribology. The phenomena on the nano scale are difficult to measure. Therefore, we have been developing new measurement and simulation methods to elucidate the nano-tribological phenomena. Using our findings and recent advancement of soft matter physics, we have been trying to create new mechanical systems. Focusing on mechanical systems in which nano-tribological phenomena essentially dominate the machine performance, we are conducting research projects for advanced mechanical systems such as automobiles, MEMS/NEMS, HDDs, and bio-tribological systems.

  

Research

Measurement and Simulation Methods for Nanotribology

Overview
In advanced mechanical systems such as automobiles and HDDs, the phenomenon at a nanoscale gap between the machine elements determines the machine performance, such as fuel consumption and recording density; therefore, elucidation of tribological phenomenon on the nano-scale is indispensable. We are developing measurement methods for friction and lubrication performance with controlling the sliding gap with a nanoscale precision. In addition, we are promoting the development of methods for visualization of the tribological phenomenon at the nanometer-gaps or nanometer-thick-liquid. Furthermore, in order to understand the nano-scale phenomena, molecular dynamics simulation are being developed in collaboration with Prof. Zhang’s laboratory of Department of Complex Systems Science.


Research themes
1. Heighly sensitve tribology and rheology measurement: Fiber wobbling method
2. Friction and adhesion force mapping of engineering surfaces in nano scale: Micro-mechanical probe
3. Dynamic observation of nanometer-thick liquid lubricant films: Vertical ellipsometric microscope
4. Moleculr dynamics simulation for investigating nanotribology


Representative publications

・Fiber wobbling method for dynamic viscoelastic measurement of liquid lubricant confined in molecularly narrow gaps, Tribology Letters, Vol. 30, 2008.6, pp. 177-189
・Dual-Axis Micro-Mechanical Probe for Independent Detection of Lateral and Vertical Forces, Applied Physics Letters, Vol. 89, 2006.12, pp. 173120-1-3
・Direct Visualization of Dewetting of Molecularly Thin Liquid Films on Solid Surfaces, Langmuir, Vol. 22, No. 16, 2006, pp. 6951-6955
・Simultaneously Measuring Lateral And Vertical Forces with Accurate Gap Control for Clarifying Lubrication Phenomena at Nanometer Gap, Tribology Letters, Vol. 37, No. 3, 2010.3, pp. 497-505
・Theoretical and Experimental Study on Two-stage-imaging Microscopy Using Ellipsometric Contrast for Real-time Visualization of Molecularly Thin Films, Review of Scientific Instruments, Vol. 84, 2013.5, pp. 053704-1-9

・Structure-based Coarse-graining for Inhomogeneous Liquid Polymer Systems, Journal of Chemical Physics, Vol. 139, No. 5, 2013.8, pp. 054901-1-11


Nanotribology for Advanced MechanicalSystems

Overview
In advanced mechanical system such as automobile engines and head/disk in HDDs, control of the sliding solid surfaces with the nanoscale gaps is essential for improvement of the machine performance. The developed measurement and simulation methods have applied to elucidation of tribological phenomena at nano-gaps in HDD, MEMS, and automotive. They have revealed tribological properties that have not been known so far in macro-scale machines.


Research themes
1. Nano-lubricaiton technology for next generation hard disk drives
2. Automotive tribology
3. Lubrication by MPC polymer films for medical devices
4. Anti-stiction coatings for nanoimprint technology and NEMS devices

Representative publications
・Shear thinning of nanometer-thick liquid lubricant films measured at high shear rates, Tribology Letters, Vol. 53, 2014.1, pp. 555-567
・Motion Picture Imaging of a Nanometer-thick Liquid Film Dewetting by Ellipsometric Microscopy with a Sub-μm Lateral Resolution, Langmuir, Vol. 24, No. 20, 2008.9, pp. 11645-11650
・Diffusive Motion of Molecules in Submonolayer Liquid Film on Solid Surface, Physical Review E, Vol. 72,No. 6, 2005. 12, pp. 061602-1-061602-7
・Measured Viscous and Dry Friction Forces in Nanometer-Thick Lubricant Film by Friction Force Microscopy with Micromechanical Probe, Tribology Letters, vol. 48, 2012.9, pp. 201-208

・Atmospheric Vapor Phase Deposition of Nanometer-thick Anti-stiction Fluoropolymer Coatings for Silicon Surfaces, Japanese Journal of Applied Physics, in press


Bio-fluid Systems

Overview
Using the findings on nanotribology on nanometer-thick fluid films, we are trying to control fluid on the nano-scale by adjusting interaction with solid surfaces and fabricated nanostructures. As a result, we aim to realize new bio-fluid systems, such as micro-fluid system for DNA separation and an artificial joint system coated with nano-thick biocompatible polymer films.


Research themes
1. Micro-fluidic device for DNA size separation
2. Nano-rheology of hydrated gel thin films
3. Nano-patterning of liquid thin films by controlling wettability using nano-structures


Representative publications
・Separation of Large DNA Molecules by Size Exclusion Chromatography-based Microchip with On-chip Concentration Structure, Japanese Journal of Applied Physics, in press
・Anisotropic shear viscosity of photoaligned liquid crystal confined in sub-micron-to-nanometer-scale gap widths revealed with simultaneously measured molecular orientation, Langmuir, 2015.9, Vol. 31, 11360-11369
・Control of Wettability of Molecularly Thin Liquid Films by Nanostructures, Langmuir, Vol. 24, 2008.2, pp. 2921-2928
・Nanoscale Patterning of Thin Liquid Films on Solid Surfaces, Applied Physics Letters, Vol. 87 (20), 2005.11.14, pp. 203108-1-203108-3
・Disjoining Pressure Measurements using a Microfabricated Groove for a Molecularly Thin Polymer Liquid Film on a Solid Surface, Journal of Chemical Physics, Vol. 121, No. 9, 2004.9, pp. 4358-4363

Japanese / English

Contact info.

Assosiate Prof. Shintaro Itoh
s_itoh (at) nuem.nagoya-u.ac.jp