When polymers are confined under nanoscale, their packing of molecular chains is perturbed, resulting in different structure and unique physical, mechanical, thermal, electrical, and optical properties. My research interests focus on the surface mechanics and interface mechanics of polymer nanostructures, thermophysical properties and thermal transport of polymer and its nanocomposites at the nanoscale, and the potential applications in energy field.
- Thermophysical properties of polymeric materials at the nanoscale
- The thermophysical properties of polymer thin films were investigated by a nano-thermomechanometry, a customer-designed scanning probe microscope technique. Finite element method simulations were performed to explain the effects of the thermal and mechanical coupling on these measurements.
- Mechanics of nanopatterned polymer structures
- The temperature and molecular weight dependence of the slumping and stability of nanoscale polymeric patterns, which were induced by nanoimprint lithography process, were investigated.
- The elastic moduli of one-dimensional (1D) polymer nanoliners are measured by surface wrinkling experiments. The dimensional dependence of the mechanical properties is carefully analyzed and related to the perturbation on the packing of molecule chains under 1D nanoconfinement.
- Thermal transport properties of polymeric materials and its nanocomposites
- The thermal conductivity of polymeric materials is measured by 3ω thermal measurements. Fullerene, clay, and graphene oxide are added into polymers to make nanocomposites to improve the thermal transport properties.
- Thermal stability and proton conductivity of Nafion and its nanocomposites
Awards and Honors
Materials Research Society (MRS) Graduate Student Award, 2006
Award of Excellence in Undergraduate Research, University of Science and Technology of China (USTC), 2001
Third Prize for Excellent Students, USTC, 1997&1999
Spectrum of Physics Scholarship, USTC, 1998
Prize for Excellent New Students, USTC, 1996
Professional Affiliation and Activities
Member of Materials Research Society (MRS)
Member of American Society of Mechanical Engineering (ASME)
Member of North America Thermal Analysis Society (NATAS)
Reviewer for Applied Physics Letters, Journal of Applied Physics, Journal of Physical Chemistry, Tribology Transactions, and MRS Proceedings
Selected Non-NIST Publications
- Zhou, J. and Komvopoulos, K., "Interfacial viscoelasticity of thin polymer films studied by nanoscale dynamic mechanical analysis," Applied Physics Letters, 90, 021910, (2007).
*Selected for the January 22, 2007 issue of Virtual Journal of Nanoscale Science & Technology.
- Zhou, J. and Komvopoulos, K., "Surface and interface viscoelastic behaviors of thin polymer films investigated by nanoindentation," Journal of Applied Physics, 100, 114329, (2006).
*Selected for the December 25, 2006 issue of Virtual Journal of Nanoscale Science & Technology.
- Zhou, J., Komvopoulos, K. and Minor, A.M., "Nanoscale plastic deformation and fracture of polymers studied by in situ nanoindentation in a transmission electron microscope", Applied Physical Letters, 88, 181908, (2006).
- Zhou, J., Komvopoulos, K., "Wear Mechanisms of Untreated and Gamma Irradiated Ultra-High Molecular Weight Polyethylene for Total Joint Replacements", ASME J. Tribol., 127, 273-279, (2005).
- 5. Zhou, J., Chakravartula, A., Pruitt, L., and Komvopoulos, K., "Tribological and Nanomechanical Properties of Unmodified and Crosslinked Ultra-High Molecular Weight Polyethylene for Total Joint Replacements," ASME J. Tribol., 126, 386-394, (2004).
1. “Nanoscale Thermal-Mechanical Probe Determination of ‘Softening Transitions’ in Thin Polymer Films”, Invited Talk, 36th Annual Conference of North American Thermal Analysis Society (Atlanta, GA, August 2008)
2. “Mechanically coupled Softening of Polymer Thin Films in Nanothermomechanometry”, Contributed Talk, Materials Research Society Annual Meeting (San Francisco, CA, March 2008)
Mechanical Engineer, NIST Associate
Electronics Materials Group
2006 to Present: Guest Researcher, Polymers Division, NIST
2001 to 2006: Graduate Student Researcher, Department of Mechanical Engineering, University of California at Berkeley
1999 to 2001: Undergraduate Research Assistant, Department of Modern Mechanics, University of Science and Technology of China
Ph.D., Mechanical Engineering, University of California at Berkeley, 2006
M.S., Mechanical Engineering, University of California at Berkeley, 2003
B.S., Modern Mechanics, University of Science and Technology of China, 2001