Nanotechnology

Nanotechnology in the High School Curriculum: From Energy Conversion to Science Ethics

What Is All the Fuss About Nanotechnology? Any given search engine will produce 1.6 million hits Nanotechnology is on the way to becoming the FIRST trillion dollar market

Nanotechnology influences almost every facet of every day life such as security and medicine.

Does Nanotechnology Address Teaching Standards? Physical science content standards 9-12 • Structure of atoms • Structure and properties of matter • Chemical reactions • Motion and forces • Conservation of energy and increase in disorder (entropy) • Interactions of energy and matter

Does Nanotechnology Address Teaching Standards? Science and technology standards • Abilities of technological design • Understanding about science and technology Science in personal and social perspectives • Personal and community health • Population growth • Natural resources • Environmental quality • Natural and human-induced hazards • Science and technology in local, national, and global challenges

Does Nanotechnology Address Teaching Standards? History and nature of science standards • Science as a human endeavor • Nature of scientific knowledge • Historical perspective

Does Nanotechnology Address Teaching Standards?

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Nanotechnology Idea

Standard it can address

The idea of “Nano” – being small

Structure of Atoms

Nanomaterials have a high surface area (nanosensors for toxins)

Structure and properties of matter, Personal and Community Health

Synthesis of nanomaterials and support chemistry (space propulsion)

Chemical Reactions

Shape Memory Alloys

Motion and Forces, Abilities of technological design, Understanding about science and technology

Nanocrystalline Solar Cells

Conservation of Energy and increase in disorder (entropy), Interactions of energy and matter, Natural Resources

Nanocoatings resistive to bacteria and Personal and Community Health, pollution Population Growth, Environmental Quality, Natural and human-induced hazards

Does Nanotechnology Address Teaching Standards? Nanotechnology Idea

Standard it can address

Nanomaterials, such as MR (magneto-resistive) fluids in security

Science and technology in local, national, and global challenges

Richard P. Feynman’s talk, “There is plenty of room at the bottom”. Feynman had a vision.

Science as a human endeavor, Nature of scientific knowledge, Historical perspective

Nanocosmetics and nanoclothing

Science as a human endeavor, Science and technology in local, national, and global challenges

Nanotechnology and Science Ethics

Science and technology in local, national, and global challenges, Science as a human endeavor, Historical perspective, Natural and human-induced hazards, Population Growth, Personal and Community Health

An Example of a Nanotechnology Experiment, Which Addresses the Standards: Constructing Nanocrystalline Solar Cells Using the Dye Extracted From Citrus Four main parts: 2. Nanolayer 3. Dye 4. Electrolyte 5. 2 electrodes

Nanocrystalline Solar Cells: The Materials: Materials • • • • • • • • • • • • • •

(2) F-SnO2glass slides Iodine and Potassium Iodide Mortar/Pestle Air Gun Surfactant (Triton X 100 or Detergent) Colloidal Titanium Dioxide Powder Nitric Acid Blackberries, raspberries, green citrus leaves etc. Masking Tape Tweezers Filter paper Binder Clips Various glassware Multi-meter

Preparation of Nanotitanium and Electrolyte Solution

Nanotitanium •

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Add 2-ml of 2,4 – Pentanedione (C5H8O2) to 100-ml of anhydrous isopropanol [ (CH3)2CHOH ] and stir covered for 20 minutes. Add 6.04-ml of titanium isopropoxide (Ti[(CH3)2CHO]4 to the solution and stir for at least 2 hours. Add 2.88-ml of distilled water and stir for another 2 hours. The solution must then age for 12 hours at room temperature. Since you now have a collodial suspension, the solvent must be evaporated off in an oven to collect the powder.

Electrolyte solution • • •

Measure out 10-ml of ethylene glycol Weigh out 0.127-g of I2 and add it to the ethylene glycol and stir. Weigh out 0.83 g of KI and add it to the same ethylene glycol.

Nanocrystalline Solar Cells Main component: Fluorine doped tin oxide conductive glass slides

Test the slide with a multimeter to determine which side is conductive

Synthesis of the Nanotitanium Suspension Procedure: • Add 9 ml (in 1 ml increments) of nitric or acetic acid (ph3-4) to six grams of titanium dioxide in a mortar and pestle. • Grinding for 30 minutes will produce a lump free paste. • 1 drop of a surfactant is then added ( triton X 100 or dish washing detergent). • Suspension is then stored and allow to equilibrate for 15 minutes.

Coating the Cell • After testing to determine which side is conductive, one of the glass slides is then masked off 1-2 mm on THREE sides with masking tape. This is to form a mold. • A couple of drops if the titanium dioxide suspension is then added and distributed across the area of the mold with a glass rod. • The slide is then set aside to dry for one minute.

Calcination of the Solar Cells • •

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After the first slide has dried the tape can be removed. The titanium dioxide layer needs to be heat sintered and this can be done by using a hot air gun that can reach a temperature of at least 450 degrees Celsius. This heating process should last 30 minutes.

Dye Preparation

• Crush 5-6 fresh berries in a mortar and pestle with 2-ml of de-ionized water. • The dye is then filter through tissue or a coffee filter and collected. • As an optional method, the dye can be purified by crushing only 2-3 berries and adding 10-ml of methanol/acetic acid/water (25:4:21 by volume)

Dye Absorption and Coating the Counter Electrode • •

Allow the heat sintered slide to cool to room temperature. Once the slide has cooled, place the slide face down in the filtered dye and allow the dye to be absorbed for 5 or more minutes.

•While the first slide is soaking, determine which side of the second slide is conducting. •Place the second slide over an open flame and move back and forth. •This will coat the second slide with a carbon catalyst layer

Assembling the Solar Cell •

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After the first slide had absorbed the dye, it is quickly rinsed with ethanol to remove any water. It is then blotted dry with tissue paper. Quickly, the two slides are placed in an offset manner together so that the layers are touching. Binder clips can be used to keep the two slides together. •One drop of a liquid iodide/iodine solution is then added between the slides. Capillary action will stain the entire inside of the slides

How Does All This Work? •

The dye absorbs light and transfers excited electrons to the TiO2.

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The electron is quickly replaced by the electrolyte added. The electrolyte in turns obtains an electron from the catalyst coated counter electrode.

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TiO2=electron acceptor; Iodide = electron donor; Dye = photochemical pump

Classroom Ideas With the Cell • Ohm’s law • Electrochemistry • Verification of Kirchhoff’s voltage law with cells in series. • Charging capacitors • Measuring current and power density • Measuring internal resistance • Powering small “no-load” motors

Using the Cell to Measure the Time Constant for an RC Circuit Materials: solar cell, Logger Pro, Graphical Analysis for Windows, Vernier LabPro, Voltage/Current probe, Pasco RC Circuit Board

Using the Cell to Measure the Time Constant for an RC Circuit Capacitor Basics: V(t) = terminal voltage, ε = EMF ( maximum voltage) , t = time, R = resistance(15KΩ), C = capacitance(1000µF)

τ = time constant = RC =(15x103)(1000x10-6)=15 seconds Equation for discharging a Capacitor

Using the Cell to Measure the Time Constant for an RC Circuit Re-arranging the equation algebraically to represent the slope formula.

What this basically says is that if you plot the natural log of the ratio of potentials versus the time the slope will equal the inverse of the time constant for this particular RC circuit.

Using the Cell to Measure the Time Constant for an RC Circuit The capacitor was first fully charged then allowed to discharge. The EMF was determine to be The voltage at t=0.

Using the examine function we can get various voltage and time data points from the graph. The natural log function can then be applied mathematically.

Using the Cell to Measure the Time Constant for an RC Circuit For a normal 1.5 V battery

For the solar cell

Using the Cell to Measure the Time Constant for an RC Circuit For the solar cell

For the battery Conclusion: The nanocrystalline solar cell could easily be used in a physics classroom to study capacitors as well as introduce the idea of harnessing the sun’s energy using nanotechnology.

Nanotechnology Curriculum Overview Summary of teaching modules in a Teacher’s Guide for nanotechnology • Measurement activity called measuring the visible understanding the invisible • Understanding surface area kinetics • Electrical applications of solar cells • Reading in nanotechnology • 15 week science ethics forum

Nanotechnology Curriculum Overview - Reading Apopka oasis reading café • Michael Crichton’s “prey” • John Robert Marlow’s “Nano”

Nanotechnology Curriculum Overview - Reading Each activity is accompanied by a nanotechnology article which includes: • Pre-reading activities such as an anticipation guide • Reading strategies such as questioning and prediction verification • Post reading strategies such as the “One Sentence Summary.

Nanotechnology and Science Ethics Based on a course offered at Yale Week • • • • • • • • • • • •

Overview (Feynman’s “There is plenty of room at the bottom”) From Fenyman to Funding: The Mighty Dollar Super intelligence Nanotechnology Life Extension and Cryonics Pharmaceutical Enrichment ( Brave New World) Threats to Global Security Strategies for Global Security ( I,Robot) Automation Enhanced humans and Immortality Environmental Effects of nanotechnology The Gap between science and ethics.

Planned Nanotechnology Activities Activities: 2. Making magnetic tiles to simulate “self assembly”. 3. Making Ferro Fluids to simulate the manufacture of projectile repellant materials. 4. Using Decanethiol Monolayer on Silver to simulate nanoparticles that resist stains and water absorbance. 5. A Microfluidic Nanofilter: Filtration of Gold Nanoparticles to simulate nanosensors. 6. Residual Stress on Nanolayers due to Thermal Heating 7. Various Shape Memory Alloy Experiments 8. Various Nanocoating experiments using bacteria

For More Information Please visit: www.bowlesphysics.com • Download this presentation • Download Teaching Modules