Ferrofluid Activity Guide



Freestanding Spherical Triboelectric Nanogenerator

Authors:

• RET Fellow: Dale H. Vajko

• RET Leadership Team: Chunhua Yao, Ben Taylor, David Gagnon, Xudong Wang, Anne Lynn Gillian-Daniel

Activity Summary

Materials are either negative or positive in nature. Using friction (i.e.: tribo) electrons movement is produced. Sliding friction and rolling friction were both tried to test the best model for the classroom. Voltage and amperage were tested for best results. A Spherical (Ovoid) model was chosen for best classroom use along with an assortment of materials for student creativity and engineering.

Audience

• Age Group: High School Students. The activity would be best though for a Physics Class though for a Unit on Electricity and Magnetism

• Audience Size: This would depend on the materials available

Time Frame

• Set-up: Once materials are ordered set-up is half an hour as the materials are made available to students to create their own version on a triboelectric nanogenerator

• Activity: Creating a triboelectric nanogenerator based on the Triboelectric Series

• Clean-up: Fifteen minutes to put away the materials in an orderly fashion for the next time

Objective(s)

• After completing the activity, participants will be able to:

1. Understand how friction between different materials creates an electric differential to lesser or greater effect

2. Apply Triboelectric principles to imagine electric models with a variety of potentials

3. Create a spherical model with materials of their choice to produce a testable voltage

Standards Addressed

● HS-PS3-1. Create a computational model to calculate the change in the energy of one component in a system when the change in energy of the other component(s) and energy flows in and out of the system are known

● HS-PS3-3. Design, build, and refine a device that works within given constraints to convert one form of energy into another form of energy

● HS-PS3-5. Develop and use a model of two objects interacting through electric or magnetic fields to illustrate the forces between objects and the changes in energy of the objects due to the interaction

Engineering principles -

• HS-ETS-ED-B Analyze input and output data and functioning of a human-built system to define opportunities to improve the system’s performance so it better meets the needs of end users while taking into account constraints

• HS-ETS-ED-D Plan and carry out a quantitative investigation with physical models or prototypes to develop evidence on the effectiveness of design solutions, leading to at least two rounds of testing and improvement

Activity Materials per student

• Breadboard

• 2 Breadboard Connectors

• 30 LED Lights (1.8 V or lower)

• Aluminum Foil (do not use rolls of aluminum tape as they have a coating)

• FEP Tape (Fluorinated Ethylene Propylene)

• Rust-Oleum Dry PTFE Lubricant

• Thin Wire for micro-amperage system

• Superballs

• Marbles Large and small

• Copper Tape Strips

• Other materials from the Triboelectric Series for student trial

• Double Sided Scotch Tape

• Shells (hollow balls anywhere from 40 mm to 220 mm - Purchase at Toys R Us - Large

whiffle balls are best. Around Easter one may purchase large plastic Easter Eggs which are oblong but work very well)

• Ammeter capable of microamp measurement (eg: Fluke 116)

• Voltmeter (the Fluke 116 works well)

Activity Instructions

Set-up

The teacher needs to have a model made to illustrate what is needed or at least show what a triboelectric generator resembles. In addition, the teacher needs to set out the materials afore mentioned for students to engineer their own nanogenerator. The materials may be set out in time for the students’ lab either the day of or the day before.

Introduction (35 min)

A discussion is necessary to set the context of the lab.

• Students need to understand Ohm’s Law relating Potential Difference to Current and Resistance.

• The concept of materials’ positive and negative natures and the Triboelectric Series need to be explained.

• The engineering and use of triboelectric nanogenerators needs to be taught (see link to my Power Point). Dr. Wang’s Youtube Video of the latter is a useful tool for the classroom.

Activity (1.5 hours)

1. Make a small hole in each halves of your hollow sphere (in our case we used an ovoid as this is what we had on hand)

2. Insert one end of one foot of very thin copper wire and tape to the inside of the respective halves using copper tape or aluminum tape

3. Line the two halves of a hollow sphere with a material higher up on the triboelectric series (see link below). In our case we used Aluminum using double sided tape (just make sure NOT to tape over the copper tape and wire)

4. Either spray with FTPE or use FEP tape (not packing tape) to wrap several spheres or use any material farther down on the triboelectric series. The more spheres inside the more surface area which is key to increasing voltage

5. Put sphere or ovoid back together making sure that the aluminum or copper from each half are well separated from each other

6. Connect each of the wires exiting each half to a multimeter and measure amps and volts. Students with then calculate wattage

7. The wires can also be connected to 1.8 V LEDS using the breadboard (keep the specs of the LEDS to 1.8V or lower. Green LEDs are best seen by the human eye) and test to see how many can be connected in series and still light up

8. Part of the procedure may be having students test different size spheres or ovoids, test

various materials for higher voltage, graph frequency of shaking vs volts

Conclusion (30 min)

Conclude by discussing students’ experience creating a prototype:

1. What did you enjoy?

2. What frustrated you?

3. What was a challenge?

4. Discuss Voltage and Ampere data

5. What produced the differences from student to student?

6. What made for the best prototype?

Assessment

• Successful construction of an operational Spherical Triboelectric Nanogenerator

• Record of amps, volts and watts of two different sized nanogenerators

• Friendly competition to see who can produce the highest wattage nanogenerator

• Use questions from Conclusion (above) as these are questions that should be asked, either verbally or in writing, to evaluate the quality of your activity and if the objectives (listed earlier) were met.

Background

• Necessary are a knowledge of Triboelectric Series, Ohm’s Law, and the Four types of Triboelectric Nanogenerators (see Introduction Above).

• All materials have either a positive or negative charge. When friction (tribo in Greek) occurs between a positive and a negative material then a charge transfer or current occurs. Using shells lined with a positive material (i.e.: aluminum or copper in my research) into which are inserted multiple small spheres of negative properties (e.g.: marbles taped with FEP or sprayed with PTFE or Teflon), shaking the closed shell will produce friction thus creating a measurable current and voltage. This model is called freestanding as the negative material (coated marbles) commute back and forth to the positive halves (copper or aluminum) thus “pushing” out electrons to an LED or a multimeter.

• Other types of models are the Contact-Sliding Mode, Vertical Contact-Separation Mode and Single-Electrode Mode.

• NOTE: humidity will prevent success of this experiment. When I did my research at the MRSEC we tested under very dry conditions with the AC during the month of July. However back in my classroom we had difficulty with hot days and high humidity. I would suggest doing this experiment either in Air Conditioning conditions or when ambient humidity is low to non-existent.

Supplemental Materials for Presentation

• You are welcome to use the Power Point Presentation of my research and the presentation I give to my students

• A Triboelectric Series Chart

• Triboelectric nanogenerators as new energy technology and self-powered sensors – Principles, problems and perspectives by Dr. Zhong Lin Wang – Use of Figure 1 in Dr. Wang’s Article is recommended to show the four types of Triboelectrics

• Triboelectric TED presentation

References

• Triboelectric Series Charts

o content/tribo-electric-series/

o science/static_materials.htm#.WkaVO9-nGMo

o

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• Dr. Zhong Lin Wang “Triboelectric nanogenerators as new energy technology and self-powered sensors – Principles, problems and perspectives” Royal Society of Chemistry: Faraday Discussions, DOI: 10.1039/c4fd00159a, Volume 176, 2014, nanoscience.gatech.edu/paper/2014/14_FD_01.pdf

ChunhuaYao, AlbertoHernandez, YanhaoYua, ZhiyongCai, XudongWang “Triboelectric nanogenerators and power-boards from cellulose nanofibrils and recycled materials”, Science Direct, Volume 30, December 2016, Pages 103-108 science/article/pii/S2211285516304086

• Hulin Zhang, Ya Yang, Yuanjie Su, Jun Chen, Katherine Adams, Sangmin Lee, Chenguo Hu, Zhong Lin Wang – “Triboelectric Nanogenerator for Harvesting Vibration Energy in Full Space and as Self-Powered Acceleration Sensor”, Advanced Functional Materials, Volume 24, Issue 10 March 12, 2014 Pages 1401–1407, DOI: 10.1002/adfm.201302453,

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MRSEC

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