Chapter 12. Modern Materials
Media Resources
Figures and Tables in Transparency Pack:
Section:
Figure 12.1 Discrete Energy Levels in Molecules
Become Continuous Bands in Solids
Table 12.1 Electronic Properties of Common
Materials
Figure 12.3 The Addition of Controlled Small
Amounts of Impurities (Doping) to a
Semiconductor Changes the Electronic
Makeup of the Material
Table 12.3 Superconducting Materials: Dates of
Discovery and Transition Temperatures
Figure 12.4 Magnetic Levitation
Figure 12.7 Unit Cell of YBa2Cu3O7
Table 12.4 Polymers of Commercial Importance
Figure 12.25 Programmable Polymers
Figure 12.26 Photograph of a Pentium 4 Processor
Computer Chip
Figure 12.28 Design of a Basic MOSFET
Figure 12.29 Schematic Illustration of the Process of
Photolithography
Figure 12.31 Liquid and Liquid Crystal
Figure 12.33 Ordering in Liquid Crystalline Phases
and a Normal (Non-Liquid Crystalline) Liquid
Figure 12.37 Schematic Illustration of the Operation
of a Twisted Nematic Liquid Crystal Display
(LCD)
Figure 12.44 Atomic Models of Carbon Nanotubes
12.1 Classes of Materials
Activities:
Section:
Band Structure
12.1 Classes of Materials
Animations:
Section:
Optical Activity
12.5 Materials for Optics
Movies:
Section:
Synthesis of Nylon 6,10
12.2 Materials for Structure
3-D Models:
Section:
Silicon Carbide
YBa2Cu3O7
Polyethylene
Polypropylene
Polystyrene
Polyvinyl Chloride
Nylon 6,6
12.1 Classes of Materials
12.1 Classes of Materials
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.1 Classes of Materials
12.1 Classes of Materials
12.1 Classes of Materials
12.1 Classes of Materials
12.1 Classes of Materials
12.2 Materials for Structure
12.3 Materials for Medicine
12.4 Materials for Electronics
12.4 Materials for Electronics
12.4 Materials for Electronics
12.5 Materials for Optics
12.5 Materials for Optics
12.5 Materials for Optics
12.6 Materials for Nanotechnology
Modern Materials 147
Fullerene
12.6 Materials for Nanotechnology
Other Resources
Further Readings:
The Future’s Bright, The Future’s Blue
Superconductors
Pictorial Analogies V: Polymers
Polymer Literature and Samples for Classroom Use
Polymers Are Everywhere
How to Learn and Have Fun with Poly(Vinyl
Alcohol) and White Glue
Polymers and Processes
Wallace Hume Carothers and Nylon, the First
Completely Synthetic Fiber
Dr. Baekland’s Bakelite
Thermosetting Resins
Elastomers I: Natural Rubber
Plastic Fantastic
Scientific American, April 1999
Contemporary Biomaterials: Understanding Surfaces
Is Key to the Design of Clinically Useful
Materials
Biomaterials and Biomedical Engineering
The Science and Applications of Biomaterials
Blending in with the Body
The Whole Body Catalogue: Replacement to Mix
and Match
The Chemistry of Modern Dental Filling Materials
Tissue Engineering
Biodegradable Elastic Shape-Memory Polymers for
Potential Biomedical Applications
Liquid Crystal Inquiries: Add a New Phase to
Your Curriculum
Liquid Crystals Display New Potential
Preparation and Properties of Cholesteric Liquid
Crystals
OLEDs Set to Glow
Shining Examples
It’s a Small World
Fishing for New Materials
Big Bucks from Small Science
The Smallest Revolution
A Tube of Tubes
Water-Filled Polymer Tubes
A Quantum Paintbox
Section:
12.1 Classes of Materials
12.1 Classes of Materials
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.2 Materials for Structure
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.3 Materials for Medicine
12.5 Materials for Optics
12.5 Materials for Optics
12.5 Materials for Optics
12.5 Materials for Optics
12.5 Materials for Optics
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
12.6 Materials for Nanotechnology
Live Demonstrations:
Section:
A Double-Decker Levitation Experiment Using a
Sandwich of Superconductors
Slime: Gelation of Poly(vinyl alcohol) with Borax
Synthesis of Nylon
12.1 Classes of Materials
12.2 Materials for Structure
12.2 Materials for Structure
148 Chapter 12
The Disappearing Coffee Cup
12.2 Materials for Structure
Modern Materials 149
Chapter 12. Modern Materials
Modern Materials
•
•
•
A goal for modern chemistry and chemists is to design materials with specific properties.
This is achieved by:
• modifying natural materials.
• synthesizing entirely new materials.
We can better understand the physical and chemical properties of materials by considering the
atomic- and molecular-level structural features of the molecules.
Lecture Outline
12.1 Classes of Materials1
•
“Materials” are substances or mixtures of substances that are linked by chemical bonds.
• The bonds may be strong (e.g., covalent, ionic, metallic) or weak (e.g., London-dispersion forces,
dipole-dipole interactions, hydrogen bonds).
Metals and Semiconductors2,3,4,5
•
•
Recall that atomic orbitals combine to make molecular orbitals.
• The number of molecular orbitals in a molecule equals the number of atomic orbitals used to
make the molecular orbitals.
• Molecules with large numbers of atoms have a very large number of molecular orbitals.
• There is essentially no separation between energy levels.
• Continuous bands of energy states are formed.
• The band structure of a solid consists of a set of bands separated by energy gaps.
Materials may be classified according to their band structure.
• Metals
• Examples include gold, silver, and platinum.
• The band structure has the highest energy electrons occupying a partially filled band.
• There is very little energy cost for electrons to jump to a higher unoccupied part of the
same band.
• As a result, metals are good electrical conductors.
• Semiconductors
• Examples include silicon, graphite, and germanium.
• The band structure has an energy gap that separates totally filled bands and empty bands.
• The band gap is the energy gap between a filled valence band and an empty conduction
band.
• The result is that semiconductors are conductive, but less so than metals due to the
presence of the band gap.
• The bonding in semiconductors is covalent-network, ionic, or a combination of the two.
• Electrical conductivity may be influenced by doping.
• Doping is the addition of small amounts of impure atoms to the semiconductors.
“The Future’s Bright, the Future’s Blue” from Further Readings
Figure 12.1 from Transparency Pack
3
Table 12.1 from Transparency Pack
4
Figure 12.3 from Transparency Pack
5
“Band Structure” Activity from Instructor’s Resource CD/DVD
1
2
150 Chapter 12
•
Doping yields different kinds of semiconductors.
• n-type: The dopant atom has more valence electrons than the host atom.
• This adds electrons to the conduction band.
• An example is phosphorous doped into silicon.
• p-type: The dopant atom has fewer valence electrons than the host atom.
• This leads to more holes in the valence band.
• An example is boron doped into silicon.
Insulators and Ceramics6
•
•
Insulators have a band structure similar to semiconductors, but they have a much larger band gap.
• The energy needed to bridge the gap is high (similar to that required to break a chemical bond).
• As a result, insulators are not electrically conductive.
• Examples include diamond and most ceramics.
Ceramics are inorganic solids that are hard, brittle, less dense than metals, stable at high
temperatures, and resistant to corrosion and wear.
Superconductors7,8,9,10,11,12
•
•
•
•
•
Superconductors show no resistance to the flow of electricity.
• Superconductivity involves the “frictionless” flow of electrons.
• Superconducting behavior only starts when the substance is cooled below the superconducting
transition temperature, Tc.
• High temperature superconductors were discovered in 1987 (YBa2Cu3O7, yttrium-barium-copper
oxide, Tc = 95 K)
• The highest Tc discovered to date is 138 K for Hg0.8Tl0.2Ba2Ca2Cu3O8.33.
• One potential use of superconductors is to carry electrical current without resistance in
generators, motors, faster computer chips, etc.
• The development of new high-temperature superconducting materials is an active area of
research.
Superconducting materials exhibit the Meissner effect, in which they exclude all magnetic fields from
their volume.
• The Meissner effect causes permanent magnets to levitate over superconductors.
• The superconductor excludes all magnetic field lines so the magnet floats in space.
• A potential application is levitated trains (“maglev”).
The first superconducting ceramic was discovered in 1986.
• It was a ceramic oxide containing yttrium, barium, and copper.
• One of the most widely studied ceramic superconductors is YBa2Cu3O7.
Most superconductors require very low temperatures in order to function.
• High-temperature superconductivity (high-Tc) will make the use of superconductors more
commercially viable.
New superconducting materials are continually being discovered.
• MgB2 and C60 reacted with an alkali metal have been shown to exhibit a superconducting
transition below about 39 K.
“Silicon Carbide” 3-D Model from Instructor’s Resource CD/DVD
Table 12.3 from Transparency Pack
8
“Superconductors” from Further Readings
9
“A Double-Decker Levitation Experiment Using a Sandwich of Superconductors” from Live
Demonstrations
10
Figure 12.4 from Transparency Pack
11
“YBa2Cu3O7” 3-D Model from Instructor’s Resource CD/DVD
12
Figure 12.7 from Transparency Pack
6
7
Modern Materials 151
12.2 Materials for Structure
Soft Materials: Polymers and Plastics13,14,15,16
•
•
•
Polymers are molecules of high molecular weight that are made by polymerization (joining together)
of smaller molecules of low molecular mass.
The building block small molecules for polymers are called monomers.
• Examples of polymers include plastics, DNA, proteins, and rubber.
Plastics are materials that can be formed into various shapes, usually with heat and pressure.
• Thermoplastic materials can be reshaped.
• Recycling of polypropylene takes advantage of this property!
• Thermosetting plastic materials are shaped by an irreversible process.
• They are not readily reshaped.
• Elastomers are materials that exhibit elastic or rubbery behavior.
• If a moderate amount of a deforming force is added, the elastomer will return to its original
shape.
Making Polymers17,18,19,20,21,22,23,24,25,26,27,28
•
•
•
Many synthetic polymers have a backbone of C–C bonds.
Carbon atoms have the ability to form unusually strong stable bonds with each other.
• Example: ethylene H2CCH2
• Ethylene can polymerize by opening the C–C bond to form C–C  bonds with adjacent
ethylene molecules.
• The result is polyethylene.
• This is an example of addition polymerization.
• Ethylene molecules are added to each other.
In condensation polymerization two molecules are joined to form a larger molecule by the
elimination of a small molecule (like water).
• An example of such a condensation reaction is when:
• an amine (R–NH2) condenses with a carboxylic acid (R–COOH) to form water and an amide.
• A biological example of this reaction is the linking of amino acids to form polymer chains–
proteins!
• A protein is an example of a copolymer–-a polymer formed from different monomers.
• Another example of condensation polymerization is the formation of nylon 6,6.
• Diamine and adipic acid are joined to form nylon 6,6.
“Pictorial Analogies V: Polymers” from Further Readings
“Polymer Literature and Samples for Classroom Use” from Further Readings
15
“Slime: Gelation of Poly(vinyl alcohol) with Borax” From Live Demonstrations
16
“Polymers are Everywhere” from Further Readings
17
“Polyethylene” 3-D Model from Instructor’s Resource CD/DVD
18
“Polypropylene” 3-D Model from Instructor’s Resource CD/DVD
19
“Polystyrene” 3-D Model from Instructor’s Resource CD/DVD
20
“Polyvinyl Chloride” 3-D Model from Instructor’s Resource CD/DVD
21
“Nylon 6,6” 3-D Model from Instructor’s Resource CD/DVD
22
“How to Learn and Have Fun with Poly(Vinyl Alcohol) and White Glue” from Further Readings
23
“Polymers and Processes” from Further Readings
24
“Wallace Hume Carothers and Nylon, the First Completely Synthetic Fiber” from Further Readings
25
Table 12.4 from Transparency Pack
26
“Dr. Baekland’s Bakelite” from Further Readings
27
“Synthesis of Nylon 6,10” Movie from Instructor’s Resource CD/DVD
28
“Synthesis of Nylon” from Live Demonstrations
13
14
152 Chapter 12
Structural and Physical Properties of Polymers29,30,31,32
•
•
•
•
•
•
•
Synthetic and natural polymers commonly consist of a collection of macromolecules of different
molecular weights.
Polymers are fairly amorphous (noncrystalline).
• Polymer chains tend to be flexible and easily entangled or folded.
• They soften over a wide range of temperatures.
• They may show some ordering.
• The degree of crystallinity reflects the extent of the order.
Stretching or extruding a polymer can increase crystallinity.
The degree of crystallinity is also strongly influenced by average molecular mass:
• Low-density polyethylene (LDPE), which is used in plastic wrap, has an average molecular mass
of 104 amu.
• High-density polyethylene (HDPE), which is used in milk cartons, has an average molecular mass
of 106 amu.
We can modify the polymeric properties by the addition of substances with lower molecular mass.
• Plasticizers are molecules that interfere with interactions between polymer chains.
• These make polymers more pliable.
Bonds formed between polymer chains make the polymer stiffer.
• Forming such bonds is referred to as cross-linking.
• The greater the number of cross-links, the more rigid the polymer becomes.
Example: Natural rubber is too soft and too chemically reactive to be useful.
• Vulcanization of rubber involves the formation of cross-links in the polymer chain.
• Rubber is cross-linked in a process employing short chains of sulfur atoms.
• Vulcanized rubber has more useful properties.
• It is more elastic and less susceptible to chemical reaction than natural rubber.
Hard Materials: Metals and Ceramics
•
•
The properties of metals make them particularly useful in everyday applications: They are ductile,
malleable, and highly conductive.
Ceramics are used in many applications.
• They are used to make cutting tools, abrasives (e.g., SiC), supports for semiconductor integrated
circuits, piezoelectric materials, and tiles for the space shuttle.
• Ceramics are brittle.
• Small defects developed during processing make ceramics weaker.
• Sintering involves heating of very pure uniform particles (< 10–6 m in diameter) at high
temperatures under pressure to force individual particles to bond together.
• Tougher ceramics may be made by adding fibers to a ceramic material.
• An example is SiC fibers added to aluminosilicate glass.
Making Ceramics
•
Sol-gel process is the formation of pure uniform particles.
• A metal alkoxide is formed [e.g., Ti(OCH2CH3)4].
• Alkoxides contain organic groups bonded to a metal atom through oxygen atoms.
• Formed by the reaction of a metal and an alcohol.
“The Disappearing Coffee Cup” from Live Demonstrations
“Thermosetting Resins” from Further Readings
31
“Elastomers I: Natural Rubber” from Further Readings
32
“Plastic Fantastic” from Further Readings
29
30
Modern Materials 153
•
For example:
•
•
•
•
•
Ti(s) + 4CH3CH2OH(l) Ti(OCH2CH3)4(s) + 2H2(g)
A sol is formed by reacting the alkoxide with water [to form Ti(OH)4].
• A sol is a suspension of extremely small particles.
A gel is formed by condensing the sol and eliminating water.
• A gel is a suspension of extremely small particles that has the consistency of gelatin.
The gel is heated to remove water and is converted into a finely divided oxide powder.
The oxide powder has particles with sizes between 0.003 and 0.1 µm in diameter.
A ceramic object is formed from the powder.
• It is compacted under pressure and scintered at high temperature.
12.3 Materials for Medicine
•
A biomaterial is any material that has a biomedical application.
• An example is a therapeutic or diagnostic use.
Characteristics of Biomaterials33,34,35,36,37,38,39
•
Choice of biomaterial for an application is influenced by the chemical characteristics.
• Biocompatibility:
• A substance is biocompatible if it is readily accepted by the body without causing an
inflammatory response.
• The chemical nature and physical texture of the object are important.
• Physical requirements:
• The material must be able to withstand the physical stresses of use.
• For example, materials used for hip-joint replacements must be wear-resistant.
• Chemical requirements:
• Must be medical grade.
• Must be innocuous over the lifetime of the application.
• For example, polymers can not contain plasticizers or other substances that might be released
and cause a problem for the patient.
Polymeric Biomaterials
•
•
Our bodies are composed of many biopolymers.
• Examples include proteins, polysaccharides (sugar polymers), and nucleic acids (DNA, RNA).
• These have complex structures with many polar groups along the polymer chain.
• The repeat unit often varies along the chain.
• For example, in proteins the monomers are amino acids.
• There are twenty different amino acids commonly found incorporated into proteins.
Man-made polymers are usually simpler.
• One or two different repeat units may be used.
• Often this contributes to the body's ability to detect these as “foreign objects.”
Examples of Biomaterial Applications40,41,42
33
Scientific American, April 1999 from Further Readings
“Contemporary Biomaterials: Understanding Surfaces Is Key to the Design of Clinically Useful
Materials” from Further Readings
35
“Biomaterials and Biochemical Engineering” from Further Readings
36
“The Science and Applications of Biomaterials” from Further Readings
37
“Blending in with the Body” from Further Readings
38
“The Whole Body Catalogue: Replacement to Mix and Match” from Further Readings
39
“The Chemistry of Modern Dental Filling Materials” from Further Readings
34
154 Chapter 12
•
•
•
•
Heart Replacement and Repairs:
• Aortic valve replacements have become common.
• There are also mechanical valves.
• They must be designed to avoid hemolysis (breakdown of red blood cells) and other
complications that may result from roughness in the surface of the material.
• They must be designed to become incorporated into the body's tissues (fixed in place).
Vascular grafts:
• These are replacements of portions of diseased arteries.
• Current materials still present the risk of blood clots.
Artificial tissue:
• This is lab-grown skin used for tissue grafts in burn patients.
• Artificial tissue is grown on a polymeric support or scaffold.
“Smart” Sutures:
• These are biodegradable sutures that hydrolyze slowly.
• Smart sutures can reversibly change their behavior in response to an external stimulus.
• They are made of a thermoplastic polymer that shrinks when heated to body temperature or
above.
• Sutures may be loosely tied by the surgeon and then become appropriately taut when warmed to
body temperature.
12.4 Materials for Electronics
The Silicon Chip43,44,45
•
•
•
Many modern devices rely on silicon wafers or “chips” containing complex patterns of
semiconductors, insulators, and metal wires.
Silicon is inexpensive, abundant, fairly nontoxic, can be chemically protected with SiO2, and can be
used to produce enormous nearly atomically perfect crystals.
The transistor is the basic unit of the integrated circuit.
• Electrons move from semiconductor “source” to semiconductor “drain” when voltage is applied
to a metal/insulator “gate.”
Plastic Electronics
•
Some polymers with delocalized electrons can act as semiconductors.
• The 2000 Nobel prize in chemistry was awarded to the discoverers of “organic semiconductors.”
Solar Energy Conversion
•
•
•
Semiconductors are also used in the production of solar energy cells.
If you shine light with an appropriate wavelength on a semiconductor, electrons are promoted to the
conduction band, making the material more conductive.
• This property is known as photoconductivity.
Solar panels are made from silicon.
• A solar cell is formed by the junction of n-type and p-type silicon.
• Sunlight promotes electrons from the n-type side to the p-type side.
“Tissue Engineering” from Further Readings
Figure 12.25 from Transparency Pack
42
“Biodegradable, Elastic Shape-Memory Polymers for Potential Biomedical Applications” from Further
Readings
43
Figure 12.26 from Transparency Pack
44
Figure 12.28 from Transparency Pack
45
Figure 12.29 from Transparency Pack
40
41
Modern Materials 155
•
This results in a current that can be used to power electrical devices.
12.5 Materials for Optics
Liquid Crystals46
•
•
•
Solids are characterized by their order.
Liquids are characterized by almost random ordering of molecules.
There is an intermediate phase where liquids show a limited amount of ordering.
• Liquid crystals are substances that exhibit one or more ordered phases at a temperature above
the melting point.
• Example: The first systematic report of a liquid crystal was cholesteryl benzoate.
• It melts at 145C.
• Between 145C and 179C cholesteryl benzoate is milky and liquid crystalline.
• At 179C the milky liquid suddenly clears.
• Cholesteryl benzoate passes through an intermediate liquid crystalline phase.
• It has some properties of liquids and some of solids.
• The liquid flows (liquid properties) but has some order (crystal properties).
Types of Liquid-Crystalline Phases47,48,49,50
•
•
46
Liquid crystal molecules are usually long and rodlike.
• In normal liquid phases they are randomly oriented.
The three types of liquid crystalline phase depend on the ordering of the molecules.
• Nematic liquid-crystalline phase (least ordered)
• Ordered along the long axis of the molecule only.
• Smectic liquid-crystalline phase
• Ordered along the long axis of the molecule and in one other dimension.
• Molecules that exist as nematic or smectic crystals are often fairly long relative to their thickness.
• Smectic liquid crystals often contain C=N bonds and benzene rings that add stiffness.
• Many contain polar groups.
• Dipole-dipole interactions promote alignment of the molecules.
• Cholesteric liquid-crystalline phase (most ordered)
• Molecules are aligned along their long axis.
• In addition, the molecules are arranged in layers.
• Molecules in each plane are twisted slightly relative to molecules in neighboring layers.
• Many of the molecules are derivatives of cholesterol.
• An example is cholesteryl octanoate.
• The molecules are long, flat, and rod-like with a flexible tail.
• The flexible tail causes the twist between the layers.
• The flexible tail usually contains many C–C bonds (e.g., the hydrocarbon tail in
cholesteryl octanoate).
• The rings in the cholesterol portion are not planar, but give the molecule a flat, sausagelike shape.
• Changes in temperature and pressure cause ordering between layers to change.
• This results in color changes.
Figure 12.31 from Transparency Pack
Figure 12.33 from Transparency Pack
48
“Liquid Crystal Inquiries: Add a New Phase to Your Curriculum” from Further Readings
49
“Liquid Crystals Display New Potential” from Further Readings
50
“Preparation and Properties of Cholesteric Liquid Crystals” from Further Readings
47
156 Chapter 12
Semiconductor Light-Emitting Diodes51,52,53,54
•
•
•
•
LEDs are light-emitting diodes.
LEDs are used in many types of displays.
The mechanism of action is the opposite of that involved in solar cells.
• A small voltage is applied to a semiconductor device with a junction between an n-type and a ptype semiconductor.
• The junction forms a n-p diode, in which electrons flow only in one direction.
• When a voltage is applied, electrons in the conduction band from the n-side combine at the
junction with the holes from the p-side.
• Light is emitted whose photons have energy equal to the band gap.
• LEDs of different visible colors may be made by appropriately “tuning” the band gap.
• Red, green, and blue LEDs are available.
Organic LEDs (OLEDs) have advantages over traditional LEDs. They are lighter, more flexible, and
may be brighter and more energy efficient.
12.6 Materials for Nanotechnology
•
Nanomaterials have dimensions on the 1 – 100 nm scale.
Semiconductors on the Nanoscale55,56,57,58,59,60,61
•
•
•
Semiconductor particles with diameters in the 1 to 10 nm range are called quantum dots.
Semiconductor band gaps change substantially with size in the 1 – 10 nm range.
• The smaller the particle is, the larger the band gap. Consider cadmium phosphide.
• On a macrolevel it looks black. The band gap is small and it absorbs most of the visible light.
• When the particle is made smaller, the color changes until it looks white.
• No visible light is absorbed.
• The band gap is so large that only uv light can excite electrons to the conduction band.
• By appropriately tuning the band gap of the quantum dots, all colors of the rainbow can be
obtained from one material.
Quantum wires have also been produced. A quantum wire is a semiconductor wire that may have a
very long length but a diameter that is only a few nanometers.
Metals on the Nanoscale
•
•
51
The mean free path of an electron is the average distance it moves before bumping into something
and is scattered.
The mean free path of an electron in a metal at room temperature is on the 1 – 100 nm scale.
• Metals with particle sizes of 1 – 100 nm have unusual properties.
• Unusual properties of metal nanoproperties that are being explored include applications in
biomedical imaging and chemical detection.
Figure 12.37 from Transparency Pack
“Optical Activity” Animation from Instructor’s Resource CD/DVD
53
“OLEDs Set to Glow” from Further Readings
54
“Shining Examples” from Further Readings
55
“It’s a Small World” from Further Readings
56
“Fishing for New Materials” from Further Readings
57
“Big Bucks from Small Science” from Further Readings
58
“The Smallest Revolution” from Further Readings
59
“A Tube of Tubes” from Further Readings
60
“Water-Filled Polymer Tubes” from Further Readings
61
“A Quantum Paintbox” from Further Readings
52
Modern Materials 157
Carbon
•
•
•
62
63
Nanotubes62,63
Carbon nanotubes are sheets of graphite rolled up and capped at one or both ends by half of a C60
molecule.
• May be either multiwall or single-walled.
• Multiwall tubes consist of tubes within tubes.
• Single-walled tubes may be 1000 nm or longer but only 1 nm in diameter.
Carbon nanotubes may be made either semiconducting or metallic without the need for doping.
Applications being explored include the development of carbon-based electronic devices.
Figure 12.44 from Transparency Pack
“Fullerene” 3-D Model from Instructor’s Resource CD/DVD
158 Chapter 12
Further Readings:
1. John Emsley, “The Future’s Bright, the Future’s Blue,” Chemistry World, March 2004, 30–33. This is
a short article on promising semiconductors.
2. Arthur B. Ellis, “Superconductors,” J. Chem. Educ., Vol. 64, 1987, 836–841.
3. John H. Fortman, “Pictorial Analogies V: Polymers,” J. Chem. Educ., Vol. 70, 1993, 403–404. Several
analogies for polymer formation are featured in this reference.
4. John J. Meister, “Polymer Literature and Samples for Classroom Use,” J. Chem. Educ., Vol. 72, 1995,
593–595. This reference provides a list of sources for suppliers of polymer samples as well as polymer
literature references.
5. Raymond B. Seymour, “Polymers Are Everywhere,” J. Chem. Educ., Vol. 65, 1988, 327–334. Uses of
polymers throughout history are outlined in this reference.
6. V. de Zea Bermudez, P. Passos de Almeida, and J. Feria Seita, “How to Learn and Have Fun with
Poly(Vinyl Alcohol) and White Glue,” J. Chem. Educ., Vol. 75, 1998, 1410–1418.
7. Melissa Lee, “Polymers and Processes,” Chemistry in Britain, Vol. 31(9), September 1998.
8. Geoerge B. Kauffman, “Wallace Hume Carothers and Nylon, the First Completely Synthetic Fiber,” J.
Chem. Educ., Vol. 65, 1988, 803–808.
9. Alan Gray, “Performance Polymers,” Chemistry in Britain, Vol. 34(3), March 1998, 44–45. This is a
short article on innovations in engineering thermoplastics.
10. Miriam C. Nagel, “Dr. Baekland's Bakelite,” J. Chem. Educ., Vol. 57, 1980, 811–812. This is a short
historical article about the scientist who prepared the first commercially successful plastic.
11. W. Peng and B. Riedl, “Thermosetting Resins,” J. Chem. Educ., Vol. 72, 1995, 587–592. A general
description of resins or thermosets, their applications and manner of curing is featured in this reference.
12. George B. Kauffman and Raymond B. Seymour, “Elastomers I: Natural Rubber,” J. Chem. Educ., Vol.
67, 1990, 422–425.
13. Michael Chisholm, “Plastic Fantastic,” Chemistry in Britain, Vol. 34(4), April 1998, 33–36. This
article looks at the uses of polymethyl methacrylate.
14. Carol Cummings, “Neoprene and Nylon Stockings: The Legacy of Wallace Hume Carothers,” J.
Chem. Educ., Vol. 61, 1984, 241–242.
15. Charles E. Carraher, Jr. and Raymond B. Seymour, “Polymer Structure–-Organic Aspects
(Definitions),” J. Chem. Educ., Vol. 65, 1988, 314–319.
16. Raymond B. Seymour, “Alkanes: Abundant, Pervasive, Important, and Essential,” J. Chem. Educ.,
Vol. 66, 1989, 59–63.
17. A. Maureen Rouhi, “Contemporary Biomaterials: Understanding Surfaces is Key to the Design of
Clinically Useful Materials,” Chemical and Engineering News, January 18, 1999, 51–63.
Modern Materials 159
18. R. Langer, “Biomaterials and Biomedical Engineering,” Chemical Engineering Science, Vol. 50,
1995, 4109.
19. D. F. Williams, “The Science and Applications of Biomaterials,” Int. J. of Materials and Product
Technology, Vol. 10, 1995, 360.
20. Andrew L. Lewis and Mike Driver, “Blending in with the Body,” J. Chem. Educ., Vol. 79, 2002, 321–
326. This is an article dealing with biomaterials.
21. “The Whole Body Catalogue: Replacement to Mix and Match,” New York Times, July 8, 1997.
22. John W. Nicholson and H. Mary Anstice, “The Chemistry of Modern Dental Filling Materials,” J.
Chem. Educ., Vol. 76, 1999, 1497–1501. This is a look at some interesting dental polymers.
23. J. A. Hubbell and R. Langer, “Tissue Engineering,” Chem. Eng. News, March 13, 1995, 42–54.
24. The April 1999 issue of Scientific American is a special issue including many articles on tissue
engineering.
25. Renata-Maria Marroum, “Liquid Crystal Inquiries: Add a New Phase to Your Curriculum,” The
Science Teacher, Vol. 65, 1996, 32–35. Liquid crystals are used as tools to demonstrate phase transitions.
26. Richard Bissell and Neville Boden, “Liquid Crystals Display New Potential,” Chemistry in Britain,
Vol. 31(1), January 1995, 38–41.
27. Graeme Patch and Gregory A. Hope, “Preparation and Properties of Cholesteric Liquid Crystals,” J.
Chem. Educ., Vol. 62, 1985, 454–455. The liquid crystal properties of cholesterol compounds are studied
as a function of temperature and composition. This reference includes instructions for the preparation of a
number of such compounds.
28. Richard Stevenson, “OLEDs Set to Glow,” Chemistry in Britain, January 2003, 33.
29. Stephen Kelly, “Shining Examples,” Chemistry in Britain, January 2003, 34–37. This is a short
article on organic light emitting molecules.
30. Philip Ball, “It’s a Small World,” Chemistry World, February 2004, 30–36.
31. Michael Gross, “Fishing for New Materials,” Chemistry World, July 2003, 33–35.
32. Michale Kenward, “Big Bucks from Small Science,” Chemistry in Britain, April 2003, 24–26.
33. Michael Gross, “The Smallest Revolution,” Chemistry in Britain, May 2002, 36–39.
34. Bethany Halford, “A Tube of Tubes,” Chem. Eng. News, August 1, 2004, 23.
35. Michael Freemantle, “Water-Filled Polymer Tubes,” Chem. Eng. News, July 12, 2004, 7.
36. Jonathan Cox, “A Quantum Paintbox,” Chemistry in Britain, September 2003, 21–25. This is a short
article on quantum dots.
160 Chapter 12
37. A. Lendlein and R. Langer, “Biodegradable, Elastic Shape-Memory Polymers for Potential
Biomedical Applications,” Science, Vol. 296, 2002, 1673–1676.
Live Demonstrations:
1. Anthony T. Jacob, Charles I. Pechmann, and Arthur B. Ellis, “A Double-Decker Levitation Experiment
Using a Sandwich of Superconductors,” J. Chem. Educ., Vol. 65, 1988, 1094–1095.
2. E. Z. Casassa, A. M. Sarquis, and C. H. Van Dyke, “The Gelation of Polyvinyl Alcohol with Borax. A
Novel Class Participation Experiment Involving the Preparation and Properties of a ‘Slime’,” J. Chem.
Educ., Vol. 63, 1986, 57–60. This is a classic demonstration of polymer formation! You can make
SLIME!!
3. Bassam Z. Shakhashiri, “‘Slime’: Gelation of Poly(vinyl alcohol) with Borax,” Chemical
Demonstrations: A Handbook for Teachers of Chemistry, Volume 3 (Madison: The University of
Wisconsin Press, 1989), pp. 362–363.
4. Bassam Z. Shakhashiri, “Solid Foams,” Chemical Demonstrations: A Handbook for Teachers of
Chemistry, Volume 3 (Madison: The University of Wisconsin Press, 1989), pp. 348–350. This is a
demonstration of the formation and destruction of solid foams.
5. Bassam Z. Shakhashiri, “Polyurethane Foam,” Chemical Demonstrations: A Handbook for Teachers of
Chemistry, Volume 1 (Madison: The University of Wisconsin Press, 1983), pp. 216–218. Polyurethane
foam is prepared in this demonstration of polymer formation.
6. Lee. R. Summerlin,, Christie L. Borgford, and Julie B. Ealy, “The Disappearing Coffee Cup,” Chemical
Demonstrations, A Sourcebook for Teachers, Volume 2 (Washington: American Chemical Society, 1988),
pp. 96. A polystyrene coffee cup is “melted” in a pool of acetone.
7. Lee. R. Summerlin, and James. L. Ealy, Jr., “Synthesis of Nylon,” Chemical Demonstrations, A
Sourcebook for Teachers, Volume 1 (Washington: American Chemical Society, 1988), pp.172–173.