I recently had an opportunity to design an all day workshop made up of Nano and Materials modules. I started with Hydrophobicity. Why? Hydro (for short) is one of the key nano concepts and it has applicability to many nanotechnologies. Following the basic hydro concept NIP module, I extended it with a “Waterproofing” challenge. Here is the basic procedure:
Present the NIP module
Set up a challenge, to “design a waterproof fabric.” I made up a story about a group of adventurer clients who needed a lightweight easy to apply waterproofing fabric “system. You should make up your own, include requirements for the team to meet (like lightweight).
- Various “substrates” cut into 4 x 4″ squares. I used 100% cotton (washed to remove any sizing), you can also use paper towels.
- 3 – 6 substances. I used a couple of hair treatments, one petroleum based; lanolin; flaxseed oil; baby oil. I had them measure out only 3g of the gel substances, the exact amount needed to cover the 4 x 4″ square and I stressed that the cloth must be covered. The oils were provided in small cups or spray bottles for application.
- Craft sticks for applying the gels, pipettes to do the bead test, also could be used with the oils application.
- Have participants write up a plan, how will they apply and test the material. We used the same “bead” test in the NIP module.
- Participants begin designing, applying substances to the substrates and testing, making observations and documenting.
- When done have them give a “recommendation” for a design, touching on reasons for their recommendation and how the requirements were met. I also had a slide of “What ifs…” what if you double layered the substrate, mixed the substances, etc. Many of them had already tried the “what ifs” and it was interesting to hear the observations, it’s also a catalyst for critical thinking.
This was part of a day long workshop for grades 9 – 14 students and teachers (high school science and technical). We had fun with this and many things came out about nano engineering, the design process, advanced materials, and the substances and substrates used.
The petroleum substance and baby oil seem to give the best waterproofing “results.” Obviously they will be wet, not dry. To illustrate curing and drying in the design process I came prepared with flaxseed oil on cotton that had been dried for several days. The dried sample performed quite differently than the wetted sample.
I also want to note that Linseed oil would be another option and that it is a form of flaxseed oil. However, since I traveled with these supplies, I avoided bringing Linseed oil. Plain glue and wax are other options too.
It was interesting to note the differences between the hair treatment substances. I made the substances a mystery, that’s why I didn’t use plain petroleum jelly and I masked the containers. The two hair treatments I used were interesting because one was petroleum based, very thick and sticky, the other hair treatment was a flaxseed based product and was much different than the flaxseed oil and the petroleum based substance, it almost evaporated as it was applied.
Both hair treatments are available in beauty supply stores, they also proved to be popular items among my audience, they knew the name but not the ingredients.
I also had an SEM image of the best performer, the Suavecito. It was clear in the image that it penetrated the substrate fibers, changed the surface, etc. This was discussed as a basic premise of Hydrophobicity.
I encourage you to try extending a NIP module yourself, it brings in more engagement and potential for further exploration, and can be designed to address many more skills such as the advanced material fabrication process.