Max Planck Intelligent Systems Colloquium, Stuttgart

11577 1510916794

Soft Materials Approaches to Carbon Nanotubes: Gels and Composites

  • Date: Nov 20, 2017
  • Time: 13:30 - 14:30
  • Speaker: Prof. Mohammad F. Islam, Department of Materials Science & Engineering, Carnegie Mellon University, Pittsburgh 
  • Location: MPI IS Stuttgart, Heisenbergstr. 3
  • Room: Seminarraum 2P 4
  • Host: Dr. Metin Sitti, Professor (Carnegie Mellon University, Pittsburgh, PA, USA)
  • Contact: officesitti@is.mpg.de

Abstract:

Carbon nanotubes combine low density with exceptional mechanical, electrical, and optical
properties. It is highly desired to harness these intrinsic nanoscale properties for macroscale
applications. I will describe surface modification assisted self‐assembly of single‐walled carbon
nanotubes into macroscopic, shape and size tunable, ultra‐lightweight and electrically
conducting networks – hydrogels and aerogels – with large surface area. The mechanical
properties of these aerogels are dictated by free rotation and sliding of nanotubes about the
junctions, which unfortunately make them fragile. Interestingly, coating the junctions and struts
with various two‐dimensional materials such as graphene and hexagonal boron nitride
suppress rotation and sliding at the junctions and stiffen the struts, enhancing Young’s moduli
and imparting emergent superelasticity, fatigue resistance and creep resistance that is preserved
over a broad temperature range (‐100–500˚C). Owing to their microstructure, both uncoated and
coated aerogels are suitable for diverse applications. For example, we have used these aerogels
to enhance elastic modulus of thermoplastic polymers by at least 40,000%. These materials also
show high capacitance that remains stable over thousands of charge/discharge cycles even at
high rates exceeding 1 V/s and under 90% compression, allowing us to construct
supercapacitors with exceptional volumetric capacitance. Furthermore, the aerogels can be
decorated with noble metals and metal oxides to fabricate electrodes for fuel cells with high
current density and stability, highly visible‐light photoactive composites using ultraviolet‐
active photocatalysts, and pseudocapacitors without compromising the mechanical properties
of the underlying scaffolds. Finally, our fabrication process also allows densification of these
aerogels to at least 400 mg/mL, reaching high Young’s moduli of 0.4 GPa, while maintaining the
microstructure, thermomechanical responses, and ultralow loss (≈0.01–0.04) of low density
aerogels.

This work has been supported by the NSF, Alfred P. Sloan Foundation, the donors of the
American Chemical Society Petroleum Research Fund, the Korea Institute of Energy Research
(KIER), DARPA, Army Research Office, and Bayer Materials.


Short bio:

Mohammad F. Islam received his Ph.D. in Physics from Lehigh University focusing on aggregation and adsorption behavior of polyelectrolytes. He then moved to the department of Physics and Astronomy at the University of Pennsylvania as a postdoctoral fellow. There he worked on colloidal systems and carbon nanotubes. Since joining Carnegie Mellon faculty, Islam has received National Science Foundation CAREER award, Alfred P. Sloan Research Fellowship, Kavli Frontiers Fellowship, and CIT George Tallman Ladd Research Award.

 
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