Blocking Oxidation Failures of Carbon Nanotubes through Selective Protection of Defects

Significance Statement

Defects in structures stimulate oxidation attacks toward defective carbon lattice and cause failure for carbon-based devices operating at a high input power. Hence, in order to improve the technological applications of carbon nanotubes, developing techniques for reducing unfavorable effects of structural defects on the carbon lattice needs to be implemented.

A metal such as aluminum which forms a thin layer of aluminum oxide thereby protecting it from further oxidation also shows huge relevance in heat transfer applications due to its high thermal conductivity and high melting point.

Researchers from University of Maryland and U.S. Army Research Laboratory led by Professor YuHuang Wang and Dr. Bryan Glaz presented a simple technique to significantly reduce the structural effects of defects in carbon nanotubes oxidation by selectively growing aluminum oxide on defect sites and experimentally show that the selective protection effectively blocks attacks by oxygen and other oxidative species in the air. A new paper describing this research was published in the peer-reviewed journal Advanced Materials.

The authors made use of atomic layer deposition technique which substitutes for both aluminum and oxygen chemistries when developing protective coating aluminum oxide on specific areas of carbon nanotubes where surface defect sites exist.

In order to provide more understanding on this deflection protection mechanism, the authors made use of high resolution scanning electron microscopy, transmission electron microscopy and Raman scattering to show characteristics of aluminum oxide-protected carbon nanotubes thin films at failure regions. Scanning electron microscopy images showed that aluminum oxide shells in failure regions evolved into nanobeads attaching on carbon nanotubes. High resolution transmission electron microscopy and electron diffraction patterns revealed amorphous aluminum oxide coating in the contact region which transformed into crystalline nanobeads in the breakdown regions.

A thermoacoustic device was fabricated by the authors from carbon nanotubes thin films protected with aluminum oxide in order to investigate the potential applications of the defect protection method. A higher power density of 6.8 Wcm-2 in air was achieved compared with unprotected control devices which also led to a higher sound pressure of 0.64 Pa with an improved audible sound pressure level of 90.1 dB compared with unprotected films.

Solving the problem of oxidation failure by the researchers can unlock further technological applications of carbon nanotubes. Moreover, the approach used in this study may be applied to other nanomaterials such as silver nanowires and graphene which can also suffer from oxidation failures.

carbon nanotubes defects oxidation failure (advances in engineering)

About the author

Dr. Chuan-Fu Sun is a professor at the Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences (FJIRSM, CAS). He received his Ph.D. in 2011 from the FJIRSM, where he conducted research on second-order nonlinear optical crystal materials. In the same year, he joined Prof. YuHuang Wang’s group as a postdoctoral research associate at the University of Maryland College Park, working on carbon nanomaterials and their applications in thermoacoustics and lithium-ion batteries. In summer 2016, he moved to the FJIRSM and began his independent career. His research group focuses on functional inorganic materials for electrochemical energy conversion and storage. Since 2016, he has served as an editorial board member for the General Chemistry. 

About the author

Dr. Bryan Glaz is a Research Engineer and Lead for the Interdisciplinary Mechanics Group at the U.S. Army Research Laboratory (ARL). He received Ph.D. and M.S. degrees in aerospace engineering from the University of Michigan, as well as a B.S. degree from the University of Florida. Prior to joining ARL in 2010, Dr. Glaz was an NSF Alliance for Graduate Education and the Professoriate Postdoctoral Research Fellow at the University of Michigan.

As the Lead for the Interdisciplinary Mechanics Group in the ARL Vehicle Technology Directorate, Dr. Glaz leads exploratory basic/applied research efforts that cut across many of the disciplines associated with mechanical and aerospace engineering; namely fluid mechanics, structural mechanics, nonlinear dynamics, and applied mathematics. 

About the author

Dr. Morihiro Okada is a Visiting Professor in the Department of Chemistry and Biochemistry at the University of Maryland. He received B.S. and Dr. Eng. Degrees from the University of Tokyo, Japan, in 1985 and 1997, respectively. He has more than two decades of industrial experience in Nippon Steel Corporation. There, he developed a PVD coating system of hard carbon films on steel and studied the scale-growth mechanism in the steel production line. He discovered magnetite whiskers on steel and invented an electron emitter that uses a single magnetite whisker and applied them to spin polarized electron emitters.

Since 2008, he has been involved in chloride mediated CVD growth of CNT arrays in Shizuoka University, Japan, and in 2011 he moved to the University of Maryland to collaborate with Prof. YuHuang Wang’s group. He has 41 patent disclosures and one US patent. 

About the author

Mr. Xiyuan Cheng is currently a Ph.D. student advised by Prof. YuHuang Wang at the University of Maryland, College Park. He received his B.S. in chemistry from Shandong University in 2009. His current research interests include the synthesis of carbon nanotubes and their applications in devices and energy technologies. 

About the author

Dr. Shashi Karna is a Senior Research Scientist of Nano-functional Materials at the Army Research Laboratory, Weapons & Materials Research Directorate, Aberdeen Proving Ground, Maryland. He received his Ph.D. (1983) and an M.Sc. (1976) degree in chemistry from Banaras Hindu University, India and B.Sc.(1973) degree in math, physics, and chemistry from Bhagalpur University in India. Karna conducts basic and applied research in nanomaterials, mentors young scientists and engineers, identifies critical science and technology areas in nanoscience relevant to Army technologies and works with Army S&E and senior leadership to develop relevant programs, identify and recommend to management chain R&D leveraging opportunities within and outside of the U.S. Department of Defense. The main focus of his research is a fundamental understanding of the structure and quantum-size properties of nano-materials and their applications in Army technologies. 

About the author

Dr. YuHuang Wang is an Associate Professor of Chemistry at the University of Maryland. His research group focuses on materials and physical chemistry of carbon nanomaterials, and their biomedical and energy applications. A central theme of his research program is exploiting defect chemistry of sp2 carbon lattices for understanding and controlling the coupling of electrons, excitons, phonons, and spin with defects in reduced dimensions. Wang received a B.S. degree in chemistry from Xiamen University, China.

He did his Ph.D. studies with the late Nobel Laureate Richard E. Smalley at Rice University, where he demonstrated cloning of single-walled carbon nanotubes and contributed to the development of the first macroscopic, neat, single-walled carbon nanotube fiber, an electrically conductive rival of Kevlar. He then joined the laboratory of Chad A. Mirkin at Northwestern University as a postdoctoral fellow, where he invented multiple techniques for high throughput high resolution molecular printing and developed a fundamental understanding of directed assembly and manipulation of nanostructures.

He has authored/co-authored more than 70 manuscripts and is an inventor of 22 patents and applications in the areas of energy nanotechnology and nanofabrication. 

Journal Reference

Chuan-Fu Sun1, Bryan J. Glaz2, Morihiro Okada1, Edward Baker III 1, Xi-Yuan Cheng1, Shashi P. Karna2, YuHuang Wang1. Blocking Oxidation Failures of Carbon Nanotubes through Selective Protection of Defects,  Advanced Materials, Vol 28 Issue 31, 2016.

[expand title=”Show Affiliations”]
  1. Department of Chemistry and Biochemistry, University of Maryland, College Park, MD, USA
  2. U.S. Army Research Laboratory, Aberdeen Proving Ground, Aberdeen, MD, USA
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