CNTs exhibit extraordinary strength and unique electrical properties, and are efficient thermal conductors. Ajayan, professor of materials science and engineering, Omkaram Nalamasu, professor of chemistry with a joint appointment in materials science and engineering developed the paper battery.
Manikoth, Ashavani Kumar, and Saravanababu Murugesan, were co-authors and lead researchers of the project. Limitations of Li-ion Battery. This restriction does not apply to personal carry-on batteries.
This film is then peeled off from substrate. Things need to be discussed at the flip side as well. Medical Sciences: in Pacemakers for the heart, in Artificial tissues using Carbon nanotubes in Cosmetics, Drug-delivery systems, in Biosensors, such as Glucose meters, Sugar meters, etc. Being Biodegradable, Light-weight and Nontoxic, flexible paper batteries have potential adaptability to power the next generation of electronics, medical devices and hybrid vehicles, allowing for radical new designs and medical technologies.
However, commercial applications may be a long way away, because nanotubes are still relatively expensive to fabricate. Thank You. Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Explore Ebooks. Bestsellers Editors' Picks All Ebooks.
Explore Audiobooks. Bestsellers Editors' Picks All audiobooks. Explore Magazines. Editors' Picks All magazines. Explore Podcasts All podcasts. Difficulty Beginner Intermediate Advanced. The tronic devices due to their unique physical properties. Car- study of Liu et al. Numerous studies in the past few years have focused There are still several open issues related to the structural on the mechanical properties of single-wall nanotubes and electronic properties of closed-ring carbon nanotubes.
Can a continuum elastic theoretical studies indicate that electronic properties, such as shell model predict the proper structure of these materials? In this work tance of the tubes, are somewhat sensitive to mechanical we address these issues related to the structural properties of deformations.
These mechanical deformations include bend- closed-ring carbon nanotubes. In Sec. One exception is the study d. We find that unlike the case studied by Yakobson et al. They developed a continuum tibuckle case. To illustrate this, we have used the Tersoff- elastic theory to treat these different distortions. With prop- Brenner potential to describe the interaction between the erly chosen parameters the continuum elastic shell model carbon atoms,24 and simulated the formation of closed-ring provided a remarkable accurate description of these deforma- carbon nanotube structures.
The two More recently, Liu et al. Interestingly, for a large range of nanotube lengths electronic properties of carbon nanotorus using the tight- we find that the lowest-energy configuration observed is binding molecular-dynamics method.
Nanotoroidal struc- characterized by only two, well localized, buckles, indepen- tures based on carbon nanotubes have been studied in the dent of the length of the corresponding nanotube.
IV we study the relative stability of the closed-ring heptagon-pentagon defects were introduced into the hexago- structures. It is important to assess the kinetic stability of nal atomaric structure of the nanotube, resulting in signifi- these structures since, as is well known, these structures are cant changes of the electronic properties.
Liu et al. Inserting Eq. This model was first used by Yakobson et al. It predicts the model provides quantitative results for the critical angle that the number of apexes increases with the square root of in which the tube buckles. Furthermore, the critical curvature the total length of the closed-ring nanotube, and decreases estimated from the shell model was in excellent agreement with the square root of the diameter of the tube.
In the limit with extensive simulation of SWNTs. Yakobson et al. For shorter tubes the situation is different, and one finds agreement between the observed and the computed deformed that for achiral nanotubes structures confirms the reliability of simulations based on the Brenner potential. The empirical form of the Brenner potential has been ad- independent of the length l. In the original formulation of the potential, its second derivatives are discontinuous.
The first is based on a geometric con- curvature for buckling is K c 5 p 2 dl 22 for long tubes, and struction of a high-energy nanoring configuration, followed K c 5 0. The other is based on tubes! The two different pathways of construction length. This critical angle for buckling is given by u c 5K c l.
The result for long tubes is u c 5 p 2 dl 21 , and for A. Optimizing a ring structure short tubes u c 5 0. For a closed-ring structure, the local curvature can be ap- In order to construct a closed-ring nanotube-based struc- proximated by K52 p L 21 , where L is the total length of the ture we geometrically fold a nanotube into a nanoring. This nanotube. Assuming that the local strain on the closed ring structure obviously is not a minimum-energy configuration.
In Fig. The results obtained for four different tube lengths are shown in the figure: , , , and The diameter of the nanotube is d The largest closed-ring structure studied is made of a tube that is '0. As can be seen in Fig. The only systematic behavior observed is that the number of buckles, and thus the number of apexes, are independent of the length of the original nanotube.
However, unlike the case shown in Fig. Conjugate gradient minimization path for a tube, the smaller diameter tube d The notation n3m3N stands for a n3m nanotube produced a perfect ring structure for a tube length corre- with N unit-cell length.
In general we find a strong correlation between the critical to contraction of the carbon-carbon bonds, and there is no length required to form a perfect ring structure and the di- compensation from the outer radius where extension of the ameter of the nanotube: nanotubes with smaller diameters carbon-carbon bonds occurs. In order to find a local will form perfect ring structure for smaller tube lengths. We minimum-energy structure of the ring configuration we uti- return to discuss the case of the tubes below.
The minimization path initially tends to elastic shell model, which provided quantitative results for relieve the tension by quenching the inner and outer walls of the critical strain and critical angle for the formation of a the ring toward each other, resulting in an increase of the single buckle, fails when multiple buckles are formed.
The angle distortion energy at the sides of the ring. Apparently elastic shell model predicts that the number of apexes grows this structure is not a local minimum on the potential-energy with the square root of the length of the original nanotube, surface since further application of the CG minimization pro- for long tubes.
Furthermore, this model predicts that the criti- cedure breaks the cylindrical symmetry of the ring, and pro- cal angle for buckling depends on the length of the apexes. In As can be seen in Fig. Only above a certain length do we find that the tubes normal carbon nanotube. Further minimization results in a form a perfect ring structure, and at this critical length the reduction of the number of apexes.
For most structures stud- buckling disappears. Be- We find that below a certain radius of about 2. As a consequence of the high initial energy of even when a single buckle is formed. For higher values of the initial nanor- than the local curvature. Reversible adiabatic folding In contrast to the method outlined in the above subsection, where we started the optimization from a closed ring, we now discuss results that are obtained from adiabatically bending an initially straight tube into a closed-ring structure.
Polygon structures formed using the geometric construc- This procedure, as will be seen, gives still new structures, not tion for different nanotube length. Note that the minimiza- seen in the previous one. Total energy versus bending angle for an adiabatic fold- ing of a nanotube. We have performed similar calculations where the initial carbon nanotube was folded adiabatically into a closed-ring structure.
The tube FIG. Buckling of a nanotube under adiabatic fold- was bent by forcing a torque on the edge atoms stepwise, and ing. The results for the total energy versus the bending results always in formation of only two buckles below a angle are shown in Fig. For small angles, the entire nanotube folds without a con- However, the critical angle at which the kinks are formed siderable change in the circular cross section. This result is in does depend on the length and diameter of the nanotube.
The agreement with the calculations of Yakobson et al. When the bending angle reaches a is that large portions of the folded nanotube resemble a critical value two kinks are formed and the nanotube buckles slightly bent nanotube, and most of the tension contributing as indicated in Figs. The first buckling point to higher energies is located in two, well-defined, buckle i.
The reason that two obvious reasons. This was also Yakobson et al. We note in passing that our procedure the case when a geometric construction followed by the CG yielded only one buckle, in agreement with the results re- minimization procedure was applied to this nanotube.
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