Superhydrophobicity

I work in a lab so I was interested in exploring how some things lying around look like under the foldscope! I chose superhydrophobicity as a theme. For context, a superhydrophobic material contains a surface that causes water droplets resting on it to bead up (with a contact angle greater than 150º). They start out chemically hydrophobic and become “super” when micro/nano sized structures are added. I found an image from wikipedia that illustrates what this means.

Image taken from Wikipedia.

I tried using my foldscope to image the surface of a superhydrophobic surface. For this, I used the surface imaging hack where the lens (x140) is directly coupled on the phone’s camera.

Image of water droplet resting on a superhydrophobic surface.
Foldscope image of the same superhydrophobic surface.

I found an article by Wired where a 2043x magnified image of the surface structure of a superhydrophobic leaf (plume poppy) was posted.

Plume Poppy magnified image.

Qualitatively the structures look slightly similar although I need to investigate this more in order to determine what I’m actually looking at.

For fun, I also looked at hydrophobic coatings. The image I took looked really similar to how the spores of fungi look under a folscope (from several previous posts on this website) and that’s how I first found out that this power actually comes from the dried spores of the Lycopodium fern!

Foldscope image of Lycopodium powder.

You can get a really cool thing called a liquid marble when you coat small droplets of water with this powder. In this case, the droplet coated in this power has a large contact angle despite sitting on a regular surface.

Liquid marble (coated with Lycopodium powder).

Apparently aphids use a special secreted wax to coat their own excrement, honeydew, into a liquid marble in order to prevent the excrement from entrapping themselves.

3 Comments Add yours

  1. Manu Prakash says:

    Beautiful post @Ian. It’s incredible to see that lycopodium powder is a biological creation. I had this same reaction the first time I realized it’s pollen.

    A couple of years ago I had done a quick calculation of how much “pine pollen” lands on a single car. It’s roughly a billion pollen for every seven cars!
    https://microcosmos.foldscope.com/?p=13123

    Welcome to the foldscope community – we are so thrilled to have you. Can’t wait to see all your creative explorations – I am sure you will inspire many more.

    Cheers
    Manu

    1. IanH3121999 says:

      Thank you! I was really shocked when I first looked at the powder under the foldscope because I didn’t realize how much pollen was contained in such a small amount of sample. It’s hard to imagine the shear scale of pollen production.

      1. Manu Prakash says:

        Indeed. Nature balances this production but it’s a lot! I wonder what else could be done with pollen?

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