Carbon Nanotubes Team S5 Laura Young Trevor Seidel Pradip Rijal Jason Savatsky

What Are They? Allotropes of carbon with a cylindrical structure Can be capped on the ends with buckyballs or open ended Composed entirely of sp 2 bonds

Why Should We Care? Unique properties Material of the future Seemingly infinite applications Possible health issues

Properties 132,000,000:1 Length- To-Diameter Ratio Diameter of 3 to 9 nm Lengths in the millimeter range Efficient electrical conductors Can act as both thermal conductors and thermal insulators

Strength SWNT compared to some common materials Young’s Modulus* Tensile Strength*Density* Steel Kevlar Rubber10, Polypropylene Glass *Values = (Carbon Nanotube Property) / (Material Property)

Reactivity Flourination Diazonium salt addition Possible catalyst

Toxicity Research is still in the early stages In rodents, carbon nanotubes have been found to cause several lung issues The needle-like shape of the fibers is similar to that of asbestos

Single-Wall Nanotube (SWNT) ArmchairZig-Zag

Multi-Walled Nanotubes (MWNT) Multiple rolled layers of graphene sheets More resistant to chemical changes than SWNTs erships_experts/uc_berkeley.htm

Four Ways to Synthesize Carbon Nanotubes Arc Discharge Laser Ablation Chemical Vapor Deposition (CVD) Ball Milling

Arc Discharge A direct current creates a high temperature discharge between two electrodes Atmosphere is composed of inert gas at a low pressure Originally used to make C 60 fullerenes Cobalt is a popular catalyst Typical yield is 30-90%

Arc Discharge Advantages Simple procedure High quality product Inexpensive Disadvantages Requires further purification Tubes tend to be short with random sizes

Laser Ablation Discovered in 1995 at Rice University Vaporizes graphite at 1200 ⁰C Helium or argon gas A hot vapor plume forms and expands and cools rapidly Carbon molecules condense to form large clusters Similar to arc discharge Yield of up to 70%

Types of Laser Ablation Pulsed – Much higher light intensity (100 kW/cm 2 ) Continuous – Much lower light intensity (12 kW/cm 2 )

Ultra Fast-pulsed Laser Ablation

Laser Ablation Advantages Good diameter control Few defects Pure product Disadvantages Expensive because of lasers and high powered equipment

Chemical Vapor Deposition Carbon is in the gas phase Energy source transfers energy to carbon molecule Common Carbon Gases – Methane – Carbon monoxide – Acetylene

After energy transfer, the carbon molecule binds to the substrate Temperature between 650 – 900 ⁰C Yield is usually about 30% One of the most common methods of carbon nanotube synthesis Chemical Vapor Deposition

Chemical Vapor Deposition Advantages Disadvantages Easy to increase scale to industrial production Large length Simple to perform Pure product Defects are common

Ball Milling Powder graphite is placed in a stainless steel container Argon gas is used Process occurs at room temperature Powder is then annealed

Combining Ball Milling and Vapor Deposition Arkema France developed the process Process generates the highest carbon purity Products have improved dispersion ball-milling-with-vapor.html

Electrical Field emission in vacuum electronics Application in electrodes, capacitors Energy storage Lithium batteries Hydrogen storage Biological sensors AFM tips DNA sequencing Applications

Electrical Application: FED Field Emission Display ( FED) -Uses electron beam to produce color images (FED) -Traditionally cathode ray tubes are used but recently more focus on using carbon nanotubes -NASA is researching this technology to use in space exploration

Energy Storage: Lithium batteries Nanotubes have the highest reversible capacity of any carbon material for use in Lithium ion batteries Nanotubes have intrinsic characteristics desired in material used as electrodes in batteries and capacitors Nanotubes are outstanding materials for super capacitor electrodes They also have a number of properties including high surface area and thermal conductivity that make them useful as electrode catalyst supports in Polymer Electrolyte Membrane (PEM) fuel cells

Energy storage: Hydrogen storage Single-walled carbon Nanotubes can store hydrogen Nano tube technology will meet the challenge of storing hydrogen and releasing them adequately in hydrogen fuel car in future Physisorption and chemisorption e mechanisms used for hydrogen storage in carbon nanotubes

Biological applications: sensing Many spherical Nano-particles have been fabricated for biological applications. Nanotubes offer some advantages relative to Nano-particles by the following aspects: 1.Larger inner volumes – can be filled with chemical or biological species. 2.Open mouths of Nano tubes make the inner surface accessible. 3.Distinct inner and outer surface can be modified separately.

Biological applications: AFM tips Resolution of ~ 12nm is achieved Carbon nanotubes as AFM probe tips: 1.Small diameter – maximum resolution

Biological applications: DNA sequencing Nanotubes fit into the grove of the DNA strand Apply voltage across CNT, different DNA base-pairs give rise to different current signals With multiple CNT, it is possible to do parallel fast DNA sequencing Top view and side view of the assembled CNT-DNA system

Paper battery Could easily be mistaken for a sheet of black paper Functions as both a lithium- ion battery and a supercapacitor Lightweight, thin, flexible Can function at a wide range of temperatures

Nanotube speakers Thin carbon nanotube films can act as speakers New generation of cheap, flat speakers Transparent, flexible, stretchable, and magnet free

Artificial muscles Aerogels made from carbon nanotubes (CNTs) can serve as electrically powered artificial muscles Sheet becomes 220% wider and thicker when voltage is applied Flexes about 3 orders of magnitude faster and generates more than 30 times the force than human muscles of the same size

Nanotube thermocell uses multiwalled carbon nanotubes as electrodes 3 times efficient than conventional Converts waste heat from industrial plants, pipelines into electricity

Nanotube Catalysts Carbon nanotubes doped with Nitrogen Reduce oxygen more effectively than platinum catalysts Not susceptible to carbon monoxide poisoning, known to deactive platinum catalysts

In Conclusion… There are many unique properties Further investigation of toxicity is needed There are many ways to synthesize Method of synthesis depends on financial needs and amount of product desired There are many exciting applications of carbon nanotubes

Questions?

References &_user=952835&_coverDate=12/30/2003&_rdoc=1&_fmt=high&_orig=search&_ sort=d&_docanchor=&view=c&_searchStrId= &_rerunOrigin=google& _acct=C &_version=1&_urlVersion=0&_userid=952835&md5=03c5f21cb 002be312d9fc81685b8914b milling-with-vapor.html milling-with-vapor.html

Group S5 Carbon Nanotubes

S5 presentation 1 rebuttal S5 agrees with the criticism made for the most part. Our approach was to briefly touch various properties of nanotubes such as reactivity and talk in detail about the application of nanotubes, so some of the slides may have little reference to the topic. We as a group feel that we should not have used filler words. Few slides in the second of the presentation were prepared by Pradip but he was unable to present the materials so we decided put few more words in those slides to help the speaker present slides prepared by him. Jason could have put more effort into his slides and rehearsed his part. The group should have taken more time to explain some of the charts and graphs. We did include the sources of graphics in the ‘Literature Cited’ section but forgot to cite each graphic towards the end of the presentation.

Presentation: Carbon Nanotubes By Group 5

 The introduction was very solid ◦ Good information was presented ◦ Initial animated graphics quickly grabbed the audience’s attention  The first half of the presentation used slides that were easy to read and follow.  Showing the summary charts of the positive and negative processes for creating carbon nanotubes was helpful as a quick comparison guide.

 Each of the speakers, especially the third, used too many “filler” words, such as “um”.  The third speaker was clearly nervous in front of the audience. It made his presentation very dry, uninteresting, and detracted from the first two presenters.  The text used in second half of the presentation began to get crowded. More slides with fewer words per slide would’ve been helpful.

 Slides (19/20) ◦ Well designed, but very basic in appearance.  Educational Value (20/20) ◦ A lot of research was presented in a very clear and understandable manner about a new field.  Graphics (19/20) ◦ Use of 3-D animation was great ◦ Made presentation more enjoyable ◦ But replace a few pictures with diagrams  Oral presentation (16/20) ◦ 1 st speaker did well ◦ 3 rd speaker was extremely nervous and unprepared  Group Analysis of Research (20/20) ◦ It was evident that plenty of research was done to give a very thorough presentation.  Overall (94/100)

Group S2 Review of Carbon Tubes Chris Heflin Rachael Houk Michael Jones

Positives The first two speakers spoke clearly and eloquently. The slides had both pictures and words, with graphics providing good insight into the intricacies of the process. The group was well prepared and answered questions well.

Negatives The third speaker read his material directly off of the slide the vast majority of the time. Also, almost every sentence contained an “Um” The second speaker spoke quickly and moved swiftly through the slides, she could have elaborated more and allowed more time for the material to sink in.

Group S3 Review of S5—Carbon Nanotubes James Kancewick Michael Koetting Bradford Lamb

Positives The introduction to the topic was simple and easy to understand, while providing enough background to follow the presentation. The slides appeared well-made and did not present too much information at any one time. The first two speakers did a good job speaking on their respective topics and were easy to follow.

Areas for Improvement The third speaker appeared unrehearsed and mostly read off the slides in an uninspired manner. More rehearsal would have helped improve the presentation greatly. The comments about safety needed some sort of research information to back up the concerns. Sometimes the presentation was moved along a little too quickly, especially with charts and graphs.

S4 Review of S5 Presentation Group S4 REVIEW of Carbon-Nanotubes

Things Done Well Did a good job of defining any technical terms used throughout the presentation. Had a nice basic informative introduction that allowed the audience to follow along in the presentation. Did an excellent job of explaining graphics. Laura and Travis had good eye contact and projection.

Things to Improve On Graphics in the first half of presentation had citations, but toward the end of presentation there were absolutely no citations for the graphics used. What article were you critiquing? Some slides were too wordy, but overall most of the slides had a nice layout.

Things To improve On Jason- Your part of the presentation contained the most interesting topics, but you were so nervous that it was hard to follow along…..Relax! Have confidence in what you are going to say and look up. Laura- use a transition or at least a statement to introduce new slides; you just read the title of the slide and proceeded to talk about the body of the slide.

Group S6 REVIEW of Carbon-Nanotubes John Baumhardt Daniel Arnold Michael Trevathan Michael Tran

Review Good color scheme for a professional presentation; however, formatting on each slide was not consistent (text sizing and bullet use). The presentation went into impressive detail on the synthesis of nanotubes. There is too much text on the application slides. Most of the group spoke very well. We would recommend that the last speaker work on his public speaking. Public speaking is not learned over night, and is an important skill to possess. Overall, it was a very interesting in the presentation.

Critique of Information During the presentation, we would have liked to have the information on the strength of nanotubes (slide 5) explained more thoroughly. The slide was changed before we realized the numbers given were ratios. There should have been a slide concluding all of the types of synthesizing nanotubes. Comparing and contrasting the multiple methods would have helped tie the information together. When presented with the multiple applications that carbon nanotubes have, it was hard to determine which ones were practical, and in what timeframe we would expect to see them in use. The slide on reactivity did not add anything to the presentation and was not tied in to the overall presentation.

Critique (continued) Our main concerns are that: – There was not any real connections between each of the synthesis methods (compare and contrast). – No timetable or discussion on the practicality of nanotube application. – Information was not always tied into the topic. Extraneous information was given. It is clear that this group extensively researched their topic, and concise organization of the material would have served to emphasize this aspect to a greater extent.